1
|
Tian X, Janes HE, Kublin JG. Statistical design and analysis of controlled human malaria infection trials. Malar J 2024; 23:133. [PMID: 38702775 PMCID: PMC11068571 DOI: 10.1186/s12936-024-04959-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 04/22/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Malaria is a potentially life-threatening disease caused by Plasmodium protozoa transmitted by infected Anopheles mosquitoes. Controlled human malaria infection (CHMI) trials are used to assess the efficacy of interventions for malaria elimination. The operating characteristics of statistical methods for assessing the ability of interventions to protect individuals from malaria is uncertain in small CHMI studies. This paper presents simulation studies comparing the performance of a variety of statistical methods for assessing efficacy of intervention in CHMI trials. METHODS Two types of CHMI designs were investigated: the commonly used single high-dose design (SHD) and the repeated low-dose design (RLD), motivated by simian immunodeficiency virus (SIV) challenge studies. In the context of SHD, the primary efficacy endpoint is typically time to infection. Using a continuous time survival model, five statistical tests for assessing the extent to which an intervention confers partial or full protection under single dose CHMI designs were evaluated. For RLD, the primary efficacy endpoint is typically the binary infection status after a specific number of challenges. A discrete time survival model was used to study the characteristics of RLD versus SHD challenge studies. RESULTS In a SHD study with the continuous time survival model, log-rank test and t-test are the most powerful and provide more interpretable results than Wilcoxon rank-sum tests and Lachenbruch tests, while the likelihood ratio test is uniformly most powerful but requires knowledge of the underlying probability model. In the discrete time survival model setting, SHDs are more powerful for assessing the efficacy of an intervention to prevent infection than RLDs. However, additional information can be inferred from RLD challenge designs, particularly using a likelihood ratio test. CONCLUSIONS Different statistical methods can be used to analyze controlled human malaria infection (CHMI) experiments, and the choice of method depends on the specific characteristics of the experiment, such as the sample size allocation between the control and intervention groups, and the nature of the intervention. The simulation results provide guidance for the trade off in statistical power when choosing between different statistical methods and study designs.
Collapse
Affiliation(s)
- Xiaowen Tian
- Department of Biostatistics, University of Washington, 3980 15th Ave NE, Seattle, WA, 98195, USA.
| | - Holly E Janes
- Department of Biostatistics, University of Washington, 3980 15th Ave NE, Seattle, WA, 98195, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
| | - James G Kublin
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
- Department of Global Health, University of Washington, 3980 15th Ave NE, Seattle, WA, 98195, USA
| |
Collapse
|
2
|
Obaldía N, Da Silva Filho JL, Núñez M, Glass KA, Oulton T, Achcar F, Wirjanata G, Duraisingh M, Felgner P, Tetteh KK, Bozdech Z, Otto TD, Marti M. Sterile protection against P. vivax malaria by repeated blood stage infection in the Aotus monkey model. Life Sci Alliance 2024; 7:e202302524. [PMID: 38158220 PMCID: PMC10756917 DOI: 10.26508/lsa.202302524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024] Open
Abstract
The malaria parasite Plasmodium vivax remains a major global public health challenge, and no vaccine is approved for use in humans. Here, we assessed whether P. vivax strain-transcendent immunity can be achieved by repeated infection in Aotus monkeys. Sterile immunity was achieved after two homologous infections, whereas subsequent heterologous challenge provided only partial protection. IgG levels based on P. vivax lysate ELISA and protein microarray increased with repeated infections and correlated with the level of homologous protection. Parasite transcriptional profiles provided no evidence of major antigenic switching upon homologous or heterologous challenge. However, we observed significant sequence diversity and transcriptional differences in the P. vivax core gene repertoire between the two strains used in the study, suggesting that partial protection upon heterologous challenge is due to molecular differences between strains rather than immune evasion by antigenic switching. Our study demonstrates that sterile immunity against P. vivax can be achieved by repeated homologous blood stage infection in Aotus monkeys, thus providing a benchmark to test the efficacy of candidate blood stage P. vivax malaria vaccines.
Collapse
Affiliation(s)
- Nicanor Obaldía
- Departamento de Investigaciones en Parasitologia, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá City, Republic of Panamá
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Harvard University, Boston, MA, USA
- https://ror.org/00vtgdb53 Wellcome Centre for Integrative Parasitology, School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Joao Luiz Da Silva Filho
- https://ror.org/00vtgdb53 Wellcome Centre for Integrative Parasitology, School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- https://ror.org/02crff812 Institute of Parasitology, Vetsuisse and Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Marlon Núñez
- Departamento de Investigaciones en Parasitologia, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá City, Republic of Panamá
| | - Katherine A Glass
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Tate Oulton
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Fiona Achcar
- https://ror.org/00vtgdb53 Wellcome Centre for Integrative Parasitology, School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- https://ror.org/02crff812 Institute of Parasitology, Vetsuisse and Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Grennady Wirjanata
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Manoj Duraisingh
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Philip Felgner
- Institute for Immunology, University of California, Irvine, CA, USA
| | - Kevin Ka Tetteh
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Thomas D Otto
- https://ror.org/00vtgdb53 Wellcome Centre for Integrative Parasitology, School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Harvard University, Boston, MA, USA
- https://ror.org/00vtgdb53 Wellcome Centre for Integrative Parasitology, School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- https://ror.org/02crff812 Institute of Parasitology, Vetsuisse and Medical Faculty, University of Zurich, Zurich, Switzerland
| |
Collapse
|
3
|
Gbedande K, Ibitokou SA, Ong ML, Degli-Esposti MA, Brown MG, Stephens R. Boosting Live Malaria Vaccine with Cytomegalovirus Vector Can Prolong Immunity through Innate and Adaptive Mechanisms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539025. [PMID: 37205446 PMCID: PMC10187235 DOI: 10.1101/2023.05.02.539025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Vaccines to persistent parasite infections have been challenging, and current iterations lack long-term protection. Cytomegalovirus (CMV) chronic vaccine vectors drive protection against SIV, tuberculosis and liver-stage malaria correlated with antigen-specific CD8 T cells with a Tem phenotype. This phenotype is likely driven by a combination of antigen-specific and innate adjuvanting effects of the vector, though these mechanisms are less well understood. Sterilizing immunity from live Plasmodium chabaudi vaccination lasts less than 200 days. While P. chabaudi-specific antibody levels remain stable after vaccination, the decay of parasite-specific T cells correlates with loss of challenge protection. Therefore, we enlisted murine CMV as a booster strategy to prolong T cell responses against malaria. To study induced T cell responses, we included P. chabaudi MSP-1 epitope B5 (MCMV-B5). We found that MCMV vector alone significantly protected against a challenge P. chabaudi infection 40-60 days later, and that MCMV-B5 was able to make B5-specific Teff, in addition to previously-reported Tem, that survive to the challenge timepoint. Used as a booster, MCMV-B5 prolonged protection from heterologous infection beyond day 200, and increased B5 TCR Tg T cell numbers, including both a highly-differentiated Tem phenotype and Teff, both previously reported to protect. B5 epitope expression was responsible for maintenance of Th1 and Tfh B5 T cells. In addition, the MCMV vector had adjuvant properties, contributing non-specifically through prolonged stimulation of IFN-γ. In vivo neutralization of IFN-γ, but not IL-12 and IL-18, late in the course of MCMV, led to loss of the adjuvant effect. Mechanistically, sustained IFN-γ from MCMV increased CD8α+ dendritic cell numbers, and led to increased IL-12 production upon Plasmodium challenge. In addition, neutralization of IFN-γ before challenge reduced the polyclonal Teff response to challenge. Our findings suggest that, as protective epitopes are defined, an MCMV vectored booster can prolong protection through the innate effects of IFN-γ.
Collapse
Affiliation(s)
- Komi Gbedande
- Department of Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555-0435
- Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Cancer Center, 205 S. Orange Avenue, Newark, NJ 07103
| | - Samad A Ibitokou
- Department of Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555-0435
| | - Monique L Ong
- Centre for Experimental Immunology, Lions Eye Institute; Nedlands, Western Australia, Australia
- Infection and Immunity Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University; Clayton, Victoria, Australia
| | - Mariapia A Degli-Esposti
- Centre for Experimental Immunology, Lions Eye Institute; Nedlands, Western Australia, Australia
- Infection and Immunity Program and Department of Microbiology, Biomedicine Discovery Institute, Monash University; Clayton, Victoria, Australia
| | - Michael G Brown
- Department of Medicine, Division of Nephrology, and the Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA
| | - Robin Stephens
- Department of Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, Galveston, TX 77555-0435
- Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Cancer Center, 205 S. Orange Avenue, Newark, NJ 07103
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX
| |
Collapse
|
4
|
Quagliata M, Papini AM, Rovero P. Malaria vaccines. Expert Opin Ther Pat 2023; 33:169-178. [PMID: 36912026 DOI: 10.1080/13543776.2023.2190884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
INTRODUCTION : Eradication of malaria remains one of the main aims of medicine. Despite progress in malaria treatment, mortality rate remains high, especially in the poorest parts of the world. Therefore, prevention through vaccines is fundamental and recent approval of the first effective vaccine reinforced this assumption. However, since the parasite cycle is complex, being composed of three stages, different types of vaccine targeting stage-specific antigens shall be developed. Moreover, the beneficial effect on vaccinated subjects can be tuned using compositions targeting different disease stages. AREA COVERED : We analysed the malaria vaccine patent landscape describing the most significant patents published after 2016, classified according to the different parasite stages targeted focusing on selected protein antigens or epitopes. We searched "malaria vaccine" on Patentscope and Espacenet. EXPERT OPINION : Pre-erythrocytic vaccines were boosted by RTS,S approval, but its partial efficacy, limited to sporozoites, calls for compositions active against other disease stages. In particular, multi-antigens vaccines could be more effective than single-stage ones, as they would activate an immune response more similar to that acquired in endemic regions. Furthermore, vaccine storage is another factor to be taken into account given the climate of the areas where malaria is widespread. More advanced technologies can lead to more effective and safer vaccines.
Collapse
Affiliation(s)
- Michael Quagliata
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, I-50019 Sesto Fiorentino, Italy
| | - Anna Maria Papini
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, I-50019 Sesto Fiorentino, Italy
| | - Paolo Rovero
- Interdepartmental Research Unit of Peptide and Protein Chemistry and Biology, Department of NeuroFarBa, University of Florence, Via Ugo Schiff 6, I-50019 Sesto Fiorentino, Italy
| |
Collapse
|
5
|
Marreiros IM, Marques S, Parreira A, Mastrodomenico V, Mounce BC, Harris CT, Kafsack BF, Billker O, Zuzarte-Luís V, Mota MM. A non-canonical sensing pathway mediates Plasmodium adaptation to amino acid deficiency. Commun Biol 2023; 6:205. [PMID: 36810637 PMCID: PMC9942083 DOI: 10.1038/s42003-023-04566-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/08/2023] [Indexed: 02/23/2023] Open
Abstract
Eukaryotes have canonical pathways for responding to amino acid (AA) availability. Under AA-limiting conditions, the TOR complex is repressed, whereas the sensor kinase GCN2 is activated. While these pathways have been highly conserved throughout evolution, malaria parasites are a rare exception. Despite auxotrophic for most AA, Plasmodium does not have either a TOR complex nor the GCN2-downstream transcription factors. While Ile starvation has been shown to trigger eIF2α phosphorylation and a hibernation-like response, the overall mechanisms mediating detection and response to AA fluctuation in the absence of such pathways has remained elusive. Here we show that Plasmodium parasites rely on an efficient sensing pathway to respond to AA fluctuations. A phenotypic screen of kinase knockout mutant parasites identified nek4, eIK1 and eIK2-the last two clustering with the eukaryotic eIF2α kinases-as critical for Plasmodium to sense and respond to distinct AA-limiting conditions. Such AA-sensing pathway is temporally regulated at distinct life cycle stages, allowing parasites to actively fine-tune replication and development in response to AA availability. Collectively, our data disclose a set of heterogeneous responses to AA depletion in malaria parasites, mediated by a complex mechanism that is critical for modulating parasite growth and survival.
Collapse
Affiliation(s)
- Inês M. Marreiros
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal ,grid.5808.50000 0001 1503 7226Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sofia Marques
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Ana Parreira
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Vincent Mastrodomenico
- grid.164971.c0000 0001 1089 6558Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA
| | - Bryan C. Mounce
- grid.164971.c0000 0001 1089 6558Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA ,grid.164971.c0000 0001 1089 6558Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, IL USA
| | - Chantal T. Harris
- grid.5386.8000000041936877XDepartment of Microbiology and Immunology, Weill Cornell Medical College, New York, NY USA ,grid.5386.8000000041936877XImmunology & Microbial Pathogenesis Graduate Program, Weill Cornell Medicine, New York, NY USA
| | - Björn F. Kafsack
- grid.5386.8000000041936877XDepartment of Microbiology and Immunology, Weill Cornell Medical College, New York, NY USA
| | - Oliver Billker
- grid.12650.300000 0001 1034 3451Molecular Infection Medicine Sweden, Molecular Biology Department, Umeå University, Umeå, S-90187 Sweden
| | - Vanessa Zuzarte-Luís
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Maria M. Mota
- grid.9983.b0000 0001 2181 4263Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| |
Collapse
|
6
|
A single dose of genetically-attenuated malaria blood-stage parasites protects against two Plasmodium species infections. Vaccine 2023; 41:1281-1285. [PMID: 36653222 DOI: 10.1016/j.vaccine.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 10/31/2022] [Accepted: 01/03/2023] [Indexed: 01/18/2023]
Abstract
Genetically-growth-attenuated blood-stage parasites were generated inPlasmodium falciparumby targeted deletion of NT1 (Nucleoside Transporter-1) gene, and Pfnt1(-) parasites only grew after providing the culture with supra-physiological concentrations of purines. Genetically-attenuatedP. yoeliint1(-)parasites induced sterile-protection against homologous blood-stage infectious challenge after immunization with single subpatent doses, which remained subpatent even in immune-compromised mice. Here, we showed that immunizations with frozen-stocks of equally-mixedP. bergheiandP. yoelii nt1(-)parasites in single subcutaneous doses, which did not lead to patent blood-stage infection, conferred sterile protection against intravenous infectious blood-stage challenge with wild-type parasites ofP. bergheiANKA andP. yoelii17X-NL strains. This data highlights the possibility that a single subcutaneous sub-patent dose of two species of genetically-growth-attenuated parasites, which can protect humans against twoPlasmodiumspp. infections, could be developed in cultures provided with supra-physiological concentrations of purines, and shipped to endemic areas as frozen-stock doses.
Collapse
|
7
|
Salkeld J, Themistocleous Y, Barrett JR, Mitton CH, Rawlinson TA, Payne RO, Hou MM, Khozoee B, Edwards NJ, Nielsen CM, Sandoval DM, Bach FA, Nahrendorf W, Ramon RL, Baker M, Ramos-Lopez F, Folegatti PM, Quinkert D, Ellis KJ, Poulton ID, Lawrie AM, Cho JS, Nugent FL, Spence PJ, Silk SE, Draper SJ, Minassian AM. Repeat controlled human malaria infection of healthy UK adults with blood-stage Plasmodium falciparum: Safety and parasite growth dynamics. Front Immunol 2022; 13:984323. [PMID: 36072606 PMCID: PMC9444061 DOI: 10.3389/fimmu.2022.984323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
In endemic settings it is known that natural malaria immunity is gradually acquired following repeated exposures. Here we sought to assess whether similar acquisition of blood-stage malaria immunity would occur following repeated parasite exposure by controlled human malaria infection (CHMI). We report the findings of repeat homologous blood-stage Plasmodium falciparum (3D7 clone) CHMI studies VAC063C (ClinicalTrials.gov NCT03906474) and VAC063 (ClinicalTrials.gov NCT02927145). In total, 24 healthy, unvaccinated, malaria-naïve UK adult participants underwent primary CHMI followed by drug treatment. Ten of these then underwent secondary CHMI in the same manner, and then six of these underwent a final tertiary CHMI. As with primary CHMI, malaria symptoms were common following secondary and tertiary infection, however, most resolved within a few days of treatment and there were no long term sequelae or serious adverse events related to CHMI. Despite detectable induction and boosting of anti-merozoite serum IgG antibody responses following each round of CHMI, there was no clear evidence of anti-parasite immunity (manifest as reduced parasite growth in vivo) conferred by repeated challenge with the homologous parasite in the majority of volunteers. However, three volunteers showed some variation in parasite growth dynamics in vivo following repeat CHMI that were either modest or short-lived. We also observed no major differences in clinical symptoms or laboratory markers of infection across the primary, secondary and tertiary challenges. However, there was a trend to more severe pyrexia after primary CHMI and the absence of a detectable transaminitis post-treatment following secondary and tertiary infection. We hypothesize that this could represent the initial induction of clinical immunity. Repeat homologous blood-stage CHMI is thus safe and provides a model with the potential to further the understanding of naturally acquired immunity to blood-stage infection in a highly controlled setting.
Collapse
Affiliation(s)
- Jo Salkeld
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Jordan R. Barrett
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Celia H. Mitton
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Ruth O. Payne
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Mimi M. Hou
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Baktash Khozoee
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Nick J. Edwards
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Carolyn M. Nielsen
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Diana Muñoz Sandoval
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Florian A. Bach
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Wiebke Nahrendorf
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Megan Baker
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | | - Doris Quinkert
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Ian D. Poulton
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Alison M. Lawrie
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Jee-Sun Cho
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Fay L. Nugent
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Philip J. Spence
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Sarah E. Silk
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Simon J. Draper
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Angela M. Minassian
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
- *Correspondence: Angela M. Minassian,
| |
Collapse
|
8
|
Ibraheem Y, Bayarsaikhan G, Inoue SI. Host immunity to Plasmodium infection: Contribution of Plasmodium berghei to our understanding of T cell-related immune response to blood-stage malaria. Parasitol Int 2022; 92:102646. [PMID: 35998816 DOI: 10.1016/j.parint.2022.102646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 10/15/2022]
Abstract
Malaria is a life-threatening disease caused by infection with Plasmodium parasites. The goal of developing an effective malaria vaccine is yet to be reached despite decades of massive research efforts. CD4+ helper T cells, CD8+ cytotoxic T cells, and γδ T cells are associated with immune responses to both liver-stage and blood-stage Plasmodium infection. The immune responses of T cell-lineages to Plasmodium infection are associated with both protection and immunopathology. Studies with mouse model of malaria contribute to our understanding of host immune response. In this paper, we focus primarily on mouse malaria model with blood-stage Plasmodium berghei infection and review our knowledge of T cell immune responses against Plasmodium infection. Moreover, we also discuss findings of experimental human studies. Uncovering the precise mechanisms of T cell-mediated immunity to Plasmodium infection can be accomplished through further investigations using mouse models of malaria with rodent Plasmodium parasites. Those findings would be invaluable to advance the efforts for development of an effective malaria vaccine.
Collapse
Affiliation(s)
- Yarob Ibraheem
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-city, Nagasaki 852-8523, Japan
| | - Ganchimeg Bayarsaikhan
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-city, Nagasaki 852-8523, Japan
| | - Shin-Ichi Inoue
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-city, Nagasaki 852-8523, Japan.
| |
Collapse
|
9
|
Kibwana E, Kapulu M, Bejon P. Controlled Human Malaria Infection Studies in Africa-Past, Present, and Future. Curr Top Microbiol Immunol 2022. [PMID: 35704094 DOI: 10.1007/82_2022_256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Controlled human infection studies have contributed significantly to the understanding of pathogeneses and treatment of infectious diseases. In malaria, deliberately infecting humans with malaria parasites was used as a treatment for neurosyphilis in the early 1920s. More recently, controlled human malaria infection (CHMI) has become a valuable, cost-effective tool to fast-track the development and evaluation of new anti-malarial drugs and/or vaccines. CHMI studies have also been used to define host/parasite interactions and immunological correlates of protection. CHMI involves infecting a small number of healthy volunteers with malaria parasites, monitoring their parasitemia and providing anti-malarial treatment when a set threshold is reached. In this review we discuss the introduction, development, and challenges of modern-day Plasmodium falciparum CHMI studies conducted in Africa, and the impact of naturally acquired immunity on infectivity and vaccine efficacy. CHMIs have shown to be an invaluable tool particularly in accelerating malaria vaccine research. Although there are limitations of CHMI studies for estimating public health impacts and for regulatory purposes, their strength lies in proof-of-concept efficacy data at an early stage of development, providing a faster way to select vaccines for further development and providing valuable insights in understanding the mechanisms of immunity to malarial infection.
Collapse
Affiliation(s)
- Elizabeth Kibwana
- Bioscience Department, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya
| | - Melissa Kapulu
- Bioscience Department, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Program, Kilifi, Kenya.
| |
Collapse
|
10
|
Chen S, Gao Y, Fan Y, Guo S, Zhou J, Liu T, Xu W. The Dynamic Change of Immune Responses Between Acute and Recurrence Stages of Rodent Malaria Infection. Front Microbiol 2022; 13:844975. [PMID: 35250958 PMCID: PMC8891988 DOI: 10.3389/fmicb.2022.844975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Malaria infections are persistent as frequent recrudescence of the disease may occur following the acute infection stage, but the different immune responses that control the acute and recrudescence stages are still largely unknown. Using single-cell RNA sequencing (scRNA-seq), we showed that the number of Th1 and plasma cells in the spleen was significantly reduced during the recurrence stage compared to the acute stage of Plasmodium chabaudi chabaudi AS (P. chabaudi) infection. Additionally, the ability of both CD4+ T cell responses and B cells to control P. chabaudi recurrence was significantly reduced compared to their roles in the control of acute infection. In contrast, the number of innate immune cells, including red pulp macrophages (RPMs), gamma delta (γδ) T cells, and Dendritic cells (DCs) were significantly increased during the recurrence stage and showed to be critical for P. chabaudi infection recurrence control. Thus, our data strongly suggest the complementary role of innate immune responses in controlling malaria recrudescence when adaptive immune responses are suppressed. These findings shed new light on the development of immune interventions against malaria.
Collapse
Affiliation(s)
- Suilin Chen
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Yuanli Gao
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Yongling Fan
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Shuai Guo
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Jian Zhou
- Institute of Immunology, Army Medical University (Third Military Medical University), Chongqing, China
- *Correspondence: Jian Zhou,
| | - Taiping Liu
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
- Taiping Liu,
| | - Wenyue Xu
- Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China
- Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
- Wenyue Xu,
| |
Collapse
|
11
|
Doolan DL. Malaria research in Australia: looking through the lens of the past towards the future. Int J Parasitol 2021; 51:1255-1263. [PMID: 34780720 DOI: 10.1016/j.ijpara.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 10/19/2022]
Abstract
Malaria remains a global health priority, with substantial resources devoted to control and intervention since the causative parasite was first identified in 1880. Major advances have been made in discovery and translational research activities aimed at prevention, treatment and control. Laboratory-based, clinical, and field-based studies have complemented public health approaches. Australian scientists have played important roles, developing and applying innovative approaches, novel research tools and cutting-edge technologies in animal and human models of disease, as well as in disease-endemic settings. This article will provide an insight into 50 years of Australian efforts to discover mechanisms and targets of immunity and pathogenesis; develop new diagnostics, drugs, vaccines, and therapeutics; and assess new public health interventions and control measures in malaria-endemic settings.
Collapse
Affiliation(s)
- Denise L Doolan
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health & Medicine, James Cook University, Cairns QLD 4878, Australia.
| |
Collapse
|
12
|
Clark IA. How diseases caused by parasites allowed a wider understanding of disease in general: my encounters with parasitology in Australia and elsewhere over the last 50 years. Int J Parasitol 2021; 51:1265-1276. [PMID: 34757090 DOI: 10.1016/j.ijpara.2021.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/18/2021] [Accepted: 10/13/2021] [Indexed: 12/18/2022]
Abstract
This is an account of how it can prove possible to carve a reasonable scientific career by following what brought most scientific thrill rather than pursue a safe, institution-directed, path. The fascination began when I noticed, quite unexpectedly, that the normal mouse immune response causes Babesia microti to die, en masse, inside circulating red cells. It eventuated that prior Bacillus Calmette Guerin infection caused the same outcome, even before the protozoal infection became patent. It also rendered mice quite immune, long term. I acquired an obsession about this telling us how little we know. Surrounded by basic immunologists, parasitologists and virologists in London, I had been given, in the days that funding was ample, the opportunity to follow any promising lead with a free hand. Through Bacillus Calmette Guerin, this meant stumbling through a set of phenomena that were in their infancies, and could be explained only through nebulous novel soluble mediators such as TNF, described the following year as causing the in vivo necrosis of tumours in mice. Beginning with malarial disease pathogenesis, I followed TNF wherever it led, into innate immunity, acute and chronic infections, neurophysiology and neurodegenerative diseases, in all of which states awareness of the role of this cytokine is still growing fast. Many of these steps can be illustrated and expanded upon in parasitic diseases. Covering the importance of TNF in the pathogenesis of neurodegenerative disease has proved to be highly illuminating, scientifically and otherwise. But the insights it has given me into understanding the temptations to which patent-owners can succumb when faced with opportunities to put money before people is not for the faint hearted. Clearly, parasitologists inhabit a much more common-good yet science-orientated, civilised, world.
Collapse
Affiliation(s)
- Ian A Clark
- Biomedical Sciences and Biochemistry, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
| |
Collapse
|
13
|
Scheunemann JF, Reichwald JJ, Korir PJ, Kuehlwein JM, Jenster LM, Hammerschmidt-Kamper C, Lewis MD, Klocke K, Borsche M, Schwendt KE, Soun C, Thiebes S, Limmer A, Engel DR, Mueller AK, Hoerauf A, Hübner MP, Schumak B. Eosinophils Suppress the Migration of T Cells Into the Brain of Plasmodium berghei-Infected Ifnar1-/- Mice and Protect Them From Experimental Cerebral Malaria. Front Immunol 2021; 12:711876. [PMID: 34659202 PMCID: PMC8514736 DOI: 10.3389/fimmu.2021.711876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 09/13/2021] [Indexed: 11/29/2022] Open
Abstract
Cerebral malaria is a potentially lethal disease, which is caused by excessive inflammatory responses to Plasmodium parasites. Here we use a newly developed transgenic Plasmodium berghei ANKA (PbAAma1OVA) parasite that can be used to study parasite-specific T cell responses. Our present study demonstrates that Ifnar1-/- mice, which lack type I interferon receptor-dependent signaling, are protected from experimental cerebral malaria (ECM) when infected with this novel parasite. Although CD8+ T cell responses generated in the spleen are essential for the development of ECM, we measured comparable parasite-specific cytotoxic T cell responses in ECM-protected Ifnar1-/- mice and wild type mice suffering from ECM. Importantly, CD8+ T cells were increased in the spleens of ECM-protected Ifnar1-/- mice and the blood-brain-barrier remained intact. This was associated with elevated splenic levels of CCL5, a T cell and eosinophil chemotactic chemokine, which was mainly produced by eosinophils, and an increase in eosinophil numbers. Depletion of eosinophils enhanced CD8+ T cell infiltration into the brain and increased ECM induction in PbAAma1OVA-infected Ifnar1-/- mice. However, eosinophil-depletion did not reduce the CD8+ T cell population in the spleen or reduce splenic CCL5 concentrations. Our study demonstrates that eosinophils impact CD8+ T cell migration and proliferation during PbAAma1OVA-infection in Ifnar1-/- mice and thereby are contributing to the protection from ECM.
Collapse
Affiliation(s)
- Johanna F Scheunemann
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Julia J Reichwald
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Patricia Jebett Korir
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Janina M Kuehlwein
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Lea-Marie Jenster
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | | | - Matthew D Lewis
- Parasitology Unit, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Katrin Klocke
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Max Borsche
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Kim E Schwendt
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Camille Soun
- Institute for Experimental Immunology and Imaging, University Hospital Essen, Essen, Germany
| | - Stephanie Thiebes
- Institute for Experimental Immunology and Imaging, University Hospital Essen, Essen, Germany
| | - Andreas Limmer
- Clinic for Anesthesiology and Intensive Care, University Hospital Essen, Essen, Germany
| | - Daniel R Engel
- Institute for Experimental Immunology and Imaging, University Hospital Essen, Essen, Germany
| | - Ann-Kristin Mueller
- Parasitology Unit, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany.,German Center for Infection Research (DZIF), Heidelberg, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Beatrix Schumak
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| |
Collapse
|
14
|
Mohanty A, Rajendran V. Mammalian host microRNA response to plasmodial infection: role as therapeutic target and potential biomarker. Parasitol Res 2021; 120:3341-3353. [PMID: 34423387 DOI: 10.1007/s00436-021-07293-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/13/2021] [Indexed: 10/20/2022]
Abstract
The appearance of increasing drug resistance in apicomplexan intracellular Plasmodium falciparum presents a significant challenge. P. falciparum infection results in cerebral malaria (CM), causing irreversible damage to the brain leading to high mortality cases. To enhance the clinical outcome of the disease, further research is required to identify new molecular targets involved in disease manifestations. Presently, the role of non-coding microRNAs (miRNAs) derived from different cells implicated in CM pathogenesis is still barely understood. Despite the absence of miRNA machinery in Plasmodium, host-parasite interactions can lead to disease severity or impart resistance to malaria. Cytoadherence and sequestration of parasitized RBCs dysregulate the miRNA profile of brain endothelial cells, leukocytes, monocytes, and platelets, disrupting blood-brain barrier integrity and activating inflammatory signaling pathways. The abundance of miRNA in blood plasma samples of CM patients directly correlates to cerebral symptoms compared to non-CM patients and healthy individuals. Moreover, the differential host-miRNA signatures distinguish P. falciparum from P. vivax infection. Here, we review the diverse functions of host-miRNA, either protective, pathogenic, or a combination of the two, which may act as prognostic markers and novel antimalarial drug targets.
Collapse
Affiliation(s)
- Abhinab Mohanty
- Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India
| | - Vinoth Rajendran
- Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, 605014, India.
| |
Collapse
|
15
|
Abstract
BACKGROUND Intermittent preventive treatment could help prevent malaria in infants (IPTi) living in areas of moderate to high malaria transmission in sub-Saharan Africa. The World Health Organization (WHO) policy recommended IPTi in 2010, but its adoption in countries has been limited. OBJECTIVES To evaluate the effects of intermittent preventive treatment (IPT) with antimalarial drugs to prevent malaria in infants living in malaria-endemic areas. SEARCH METHODS We searched the following sources up to 3 December 2018: the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library), MEDLINE (PubMed), Embase (OVID), LILACS (Bireme), and reference lists of articles. We also searched the metaRegister of Controlled Trials (mRCT) and the WHO International Clinical Trials Registry Platform (ICTRP) portal for ongoing trials up to 3 December 2018. SELECTION CRITERIA We included randomized controlled trials (RCTs) that compared IPT to placebo or no intervention in infants (defined as young children aged between 1 to 12 months) in malaria-endemic areas. DATA COLLECTION AND ANALYSIS The primary outcome was clinical malaria (fever plus asexual parasitaemia). Two review authors independently assessed trials for inclusion, evaluated the risk of bias, and extracted data. We summarized dichotomous outcomes and count data using risk ratios (RR) and rate ratios respectively, and presented all measures with 95% confidence intervals (CIs). We extracted protective efficacy values and their 95% CIs; when an included trial did not report this data, we calculated these values from the RR or rate ratio with its 95% CI. Where appropriate, we combined data in meta-analyses and assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS We included 12 trials that enrolled 19,098 infants; all were conducted in sub-Saharan Africa. Three trials were cluster-RCTs. IPTi with sulfadoxine-pyrimethamine (SP) was evaluated in 10 trials from 1999 to 2013 (n = 15,256). Trials evaluating ACTs included dihydroartemisinin-piperaquine (1 trial, 147 participants; year 2013), amodiaquine-artesunate (1 study, 684 participants; year 2008), and SP-artesunate (1 trial, 676 participants; year 2008). The earlier studies evaluated IPTi with SP, and were conducted in Tanzania (in 1999 and 2006), Mozambique (2004), Ghana (2004 to 2005), Gabon (2005), Kenya (2008), and Mali (2009). One trial evaluated IPTi with amodiaquine in Tanzania (2000). Later studies included three conducted in Kenya (2008), Tanzania (2008), and Uganda (2013), evaluating IPTi in multiple trial arms that included artemisinin-based combination therapy (ACT). Although the effect size varied over time and between drugs, overall IPTi impacts on the incidence of clinical malaria overall, with a 30% reduction (rate ratio 0.70, 0.62 to 0.80; 10 studies, 10,602 participants). The effect of SP appeared to attenuate over time, with trials conducted after 2009 showing little or no effect of the intervention. IPTi with SP probably resulted in fewer episodes of clinical malaria (rate ratio 0.78, 0.69 to 0.88; 8 trials, 8774 participants, moderate-certainty evidence), anaemia (rate ratio 0.82, 0.68 to 0.98; 6 trials, 7438 participants, moderate-certainty evidence), parasitaemia (rate ratio 0.66, 0.56 to 0.79; 1 trial, 1200 participants, moderate-certainty evidence), and fewer hospital admissions (rate ratio 0.85, 0.78 to 0.93; 7 trials, 7486 participants, moderate-certainty evidence). IPTi with SP probably made little or no difference to all-cause mortality (risk ratio 0.93, 0.74 to 1.15; 9 trials, 14,588 participants, moderate-certainty evidence). Since 2009, IPTi trials have evaluated ACTs and indicate impact on clinical malaria and parasitaemia. A small trial of DHAP in 2013 shows substantive effects on clinical malaria (RR 0.42, 0.33 to 0.54; 1 trial, 147 participants, moderate-certainty evidence) and parasitaemia (moderate-certainty evidence). AUTHORS' CONCLUSIONS In areas of sub-Saharan Africa, giving antimalarial drugs known to be effective against the malaria parasite at the time to infants as IPT probably reduces the risk of clinical malaria, anaemia, and hospital admission. Evidence from SP studies over a 19-year period shows declining efficacy, which may be due to increasing drug resistance. Combinations with ACTs appear promising as suitable alternatives for IPTi.
Collapse
Affiliation(s)
- Ekpereonne B Esu
- Department of Public Health, College of Medical Sciences, University of Calabar, Calabar, Nigeria
| | - Chioma Oringanje
- GIDP Entomology and Insect Science, University of Tucson, Tucson, Arizona, USA
| | - Martin M Meremikwu
- Department of Paediatrics, University of Calabar Teaching Hospital, Calabar, Nigeria
| |
Collapse
|
16
|
Cai J, Chen S, Zhu F, Lu X, Liu T, Xu W. Whole-Killed Blood-Stage Vaccine: Is It Worthwhile to Further Develop It to Control Malaria? Front Microbiol 2021; 12:670775. [PMID: 33995336 PMCID: PMC8119638 DOI: 10.3389/fmicb.2021.670775] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/08/2021] [Indexed: 01/09/2023] Open
Abstract
Major challenges have been encountered regarding the development of highly efficient subunit malaria vaccines, and so whole-parasite vaccines have regained attention in recent years. The whole-killed blood-stage vaccine (WKV) is advantageous as it can be easily manufactured and efficiently induced protective immunity against a blood-stage challenge, as well as inducing cross-stage protection against both the liver and sexual-stages. However, it necessitates a high dose of parasitized red blood cell (pRBC) lysate for immunization, and this raises concerns regarding its safety and low immunogenicity. Knowledge of the major components of WKV that can induce or evade the host immune response, and the development of appropriate human-compatible adjuvants will greatly help to optimize the WKV. Therefore, we argue that the further development of the WKV is worthwhile to control and potentially eradicate malaria worldwide.
Collapse
Affiliation(s)
- Jingjing Cai
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China
| | - Suilin Chen
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Feng Zhu
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Xiao Lu
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Taiping Liu
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| | - Wenyue Xu
- College of Basic Medicine, Army Medical University (Third Military Medical University), Chongqing, China.,Department of Pathogenic Biology, Army Medical University (Third Military Medical University), Chongqing, China.,Key Laboratory of Extreme Environmental Medicine, Ministry of Education of China, Chongqing, China
| |
Collapse
|
17
|
Nevagi RJ, Good MF, Stanisic DI. Plasmodium infection and drug cure for malaria vaccine development. Expert Rev Vaccines 2021; 20:163-183. [PMID: 33428505 DOI: 10.1080/14760584.2021.1874923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Introduction: Despite decades of research into the development of a vaccine to combat the malaria parasite, a highly efficacious malaria vaccine is not yet available. Different whole parasite-based vaccine approaches, including deliberate Plasmodium infection and drug cure (IDC), have been evaluated in pre-clinical and early phase clinical trials. The advantage of whole parasite vaccines is that they induce immune responses against multiple parasite antigens, thus lowering the impact of antigenic diversity. Deliberate Plasmodium IDC, as a vaccine approach, involves administering infectious, live parasites in combination with an anti-malarial drug, which controls the infection and enables induction of protective immune responses.
Collapse
Affiliation(s)
- Reshma J Nevagi
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia
| | - Michael F Good
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia
| | - Danielle I Stanisic
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia
| |
Collapse
|
18
|
Woolley SD, Fernandez M, Rebelo M, Llewellyn SA, Marquart L, Amante FH, Jennings HE, Webster R, Trenholme K, Chalon S, Moehrle JJ, McCarthy JS, Barber BE. Development and evaluation of a new Plasmodium falciparum 3D7 blood stage malaria cell bank for use in malaria volunteer infection studies. Malar J 2021; 20:93. [PMID: 33593375 PMCID: PMC7885253 DOI: 10.1186/s12936-021-03627-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 02/05/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND New anti-malarial therapeutics are required to counter the threat of increasing drug resistance. Malaria volunteer infection studies (VIS), particularly the induced blood stage malaria (IBSM) model, play a key role in accelerating anti-malarial drug development. Supply of the reference 3D7-V2 Plasmodium falciparum malaria cell bank (MCB) is limited. This study aimed to develop a new MCB, and compare the safety and infectivity of this MCB with the existing 3D7-V2 MCB, in a VIS. A second bank (3D7-V1) developed in 1995 was also evaluated. METHODS The 3D7-V2 MCB was expanded in vitro using a bioreactor to produce a new MCB designated 3D7-MBE-008. This bank and 3D7-V1 were then evaluated using the IBSM model, where healthy participants were intravenously inoculated with blood-stage parasites. Participants were treated with artemether-lumefantrine when parasitaemia or clinical thresholds were reached. Safety, infectivity and parasite growth and clearance were evaluated. RESULTS The in vitro expansion of 3D7-V2 produced 200 vials of the 3D7-MBE-008 MCB, with a parasitaemia of 4.3%. This compares to 0.1% in the existing 3D7-V2 MCB, and < 0.01% in the 3D7-V1 MCB. All four participants (two per MCB) developed detectable P. falciparum infection after inoculation with approximately 2800 parasites. For the 3D7-MBE-008 MCB, the parasite multiplication rate of 48 h (PMR48) using non-linear mixed effects modelling was 34.6 (95% CI 18.5-64.6), similar to the parental 3D7-V2 line; parasitaemia in both participants exceeded 10,000/mL by day 8. Growth of the 3D7-V1 was slower (PMR48 of 11.5 [95% CI 8.5-15.6]), with parasitaemia exceeding 10,000 parasites/mL on days 10 and 8.5. Rapid parasite clearance followed artemether-lumefantrine treatment in all four participants, with clearance half-lives of 4.01 and 4.06 (weighted mean 4.04 [95% CI 3.61-4.57]) hours for 3D7-MBE-008 and 4.11 and 4.52 (weighted mean 4.31 [95% CI 4.16-4.47]) hours for 3D7-V1. A total of 59 adverse events occurred; most were of mild severity with three being severe in the 3D7-MBE-008 study. CONCLUSION The safety, growth and clearance profiles of the expanded 3D7-MBE-008 MCB closely resemble that of its parent, indicating its suitability for future studies. TRIAL REGISTRATION Australian New Zealand Clinical Trials registry numbers: P3487 (3D7-V1): ACTRN12619001085167. P3491 (3D7-MBE-008): ACTRN12619001079134.
Collapse
Affiliation(s)
- Stephen D Woolley
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
- Centre for Defence Pathology, Royal Centre for Defence Medicine, Joint Hospital Group, ICT Building, Birmingham Research Park, Vincent Drive, Birmingham, UK
- Clinical Sciences Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | | | - Maria Rebelo
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | | | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Fiona H Amante
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Helen E Jennings
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Rebecca Webster
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Katharine Trenholme
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
- School of Medicine, University of Queensland, Herston, QLD, Australia
| | - Stephan Chalon
- Medicines for Malaria Venture, 20 Route de Pre-Bois, PO Box 1826, 1215, Geneva 15, Switzerland
| | - Joerg J Moehrle
- Medicines for Malaria Venture, 20 Route de Pre-Bois, PO Box 1826, 1215, Geneva 15, Switzerland
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Bridget E Barber
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
| |
Collapse
|
19
|
Ghosh D, Stumhofer JS. The spleen: "epicenter" in malaria infection and immunity. J Leukoc Biol 2021; 110:753-769. [PMID: 33464668 PMCID: PMC8518401 DOI: 10.1002/jlb.4ri1020-713r] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 12/14/2022] Open
Abstract
The spleen is a complex secondary lymphoid organ that plays a crucial role in controlling blood‐stage infection with Plasmodium parasites. It is tasked with sensing and removing parasitized RBCs, erythropoiesis, the activation and differentiation of adaptive immune cells, and the development of protective immunity, all in the face of an intense inflammatory environment. This paper describes how these processes are regulated following infection and recognizes the gaps in our current knowledge, highlighting recent insights from human infections and mouse models.
Collapse
Affiliation(s)
- Debopam Ghosh
- Department of Pediatrics, Stanford University, Stanford, California, USA
| | - Jason S Stumhofer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| |
Collapse
|
20
|
Bucşan AN, Williamson KC. Setting the stage: The initial immune response to blood-stage parasites. Virulence 2020; 11:88-103. [PMID: 31900030 PMCID: PMC6961725 DOI: 10.1080/21505594.2019.1708053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 01/22/2023] Open
Abstract
Individuals growing up in malaria endemic areas gradually develop protection against clinical malaria and passive transfer experiments in humans have demonstrated that this protection is mediated in part by protective antibodies. However, neither the target antigens, specific effector mechanisms, nor the role of continual parasite exposure have been elucidated, which complicates vaccine development. Progress has been made in defining the innate signaling pathways activated by parasite components, including DNA, RNA, hemozoin, and phospholipids, which initiate the immune response and will be the focus of this review. The challenge that remains within the field is to understand the role of these early responses in the development of protective adaptive responses that clear iRBC and block merozoite invasion so that optimal vaccines and therapeutics may be produced.
Collapse
Affiliation(s)
- Allison N. Bucşan
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Kim C. Williamson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| |
Collapse
|
21
|
Apte SH, Minigo G, Groves PL, Spargo JC, Plebanski M, Grigg MJ, Kenangalem E, Burel JG, Loughland JR, Flanagan KL, Piera KA, William T, Price RN, Woodberry T, Barber BE, Anstey NM, Doolan DL. A population of CD4 hiCD38 hi T cells correlates with disease severity in patients with acute malaria. Clin Transl Immunology 2020; 9:e1209. [PMID: 33282291 PMCID: PMC7684974 DOI: 10.1002/cti2.1209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/08/2020] [Accepted: 10/20/2020] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE CD4+ T cells are critical mediators of immunity to Plasmodium spp. infection, but their characteristics during malarial episodes and immunopathology in naturally infected adults are poorly defined. Flow cytometric analysis of PBMCs from patients with either P. falciparum or P. knowlesi malaria revealed a pronounced population of CD4+ T cells co-expressing very high levels of CD4 and CD38 we have termed CD4hiCD38hi T cells. We set out to gain insight into the function of these novel cells. METHODS CD4+ T cells from 18 patients with P. falciparum or P. knowlesi malaria were assessed by flow cytometry and sorted into populations of CD4hiCD38hi or CD4norm T cells. Gene expression in the sorted populations was assessed by qPCR and NanoString. RESULTS CD4hiCD38hi T cells expressed high levels of CD4 mRNA and canonical type 1 regulatory T-cell (TR1) genes including IL10, IFNG, LAG3 and HAVCR2 (TIM3), and other genes with relevance to cell migration and immunomodulation. These cells increased in proportion to malaria disease severity and were absent after parasite clearance with antimalarials. CONCLUSION In naturally infected adults with acute malaria, a prominent population of type 1 regulatory T cells arises that can be defined by high co-expression of CD4 and CD38 (CD4hiCD38hi) and that correlates with disease severity in patients with falciparum malaria. This study provides fundamental insights into T-cell biology, including the first evidence that CD4 expression is modulated at the mRNA level. These findings have important implications for understanding the balance between immunity and immunopathology during malaria.
Collapse
Affiliation(s)
- Simon H Apte
- Infectious Diseases ProgramQIMR Berghofer Medical Research InstituteBrisbaneQLDAustralia,Present address:
Queensland Lung Transplant Service, The Prince Charles HospitalChermsideQLDAustralia
| | - Gabriela Minigo
- Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Charles Darwin UniversityDarwinNTAustralia
| | - Penny L Groves
- Infectious Diseases ProgramQIMR Berghofer Medical Research InstituteBrisbaneQLDAustralia
| | - Jessie C Spargo
- Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Charles Darwin UniversityDarwinNTAustralia
| | - Magdalena Plebanski
- Department of Immunology and PathologyMonash UniversityPrahranVICAustralia,School of Health and Biomedical SciencesRMIT UniversityBundooraVICAustralia
| | - Mathew J Grigg
- Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Charles Darwin UniversityDarwinNTAustralia
| | - Enny Kenangalem
- Papuan Health and Community Development FoundationTimikaIndonesia
| | - Julie G Burel
- Infectious Diseases ProgramQIMR Berghofer Medical Research InstituteBrisbaneQLDAustralia,Present address:
La Jolla Institute for ImmunologyLa JollaCAUSA
| | - Jessica R Loughland
- Infectious Diseases ProgramQIMR Berghofer Medical Research InstituteBrisbaneQLDAustralia,Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Charles Darwin UniversityDarwinNTAustralia
| | - Katie L Flanagan
- Department of Immunology and PathologyMonash UniversityPrahranVICAustralia,School of Health and Biomedical SciencesRMIT UniversityBundooraVICAustralia,School of MedicineUniversity of TasmaniaLauncestonTASAustralia
| | - Kim A Piera
- Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Charles Darwin UniversityDarwinNTAustralia
| | - Timothy William
- School of MedicineUniversity of TasmaniaLauncestonTASAustralia
| | - Ric N Price
- Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Nuffield Department of Clinical MedicineCentre for Tropical Medicine and Global HealthUniversity of OxfordOxfordUK,Mahidol‐Oxford Tropical Medicine Research UnitFaculty of Tropical MedicineMahidol UniversityBangkokThailand
| | - Tonia Woodberry
- Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Charles Darwin UniversityDarwinNTAustralia
| | - Bridget E Barber
- Infectious Diseases ProgramQIMR Berghofer Medical Research InstituteBrisbaneQLDAustralia,Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia,Charles Darwin UniversityDarwinNTAustralia
| | - Nicholas M Anstey
- Global and Tropical Health DivisionMenzies School of Health ResearchCasuarinaNTAustralia
| | - Denise L Doolan
- Infectious Diseases ProgramQIMR Berghofer Medical Research InstituteBrisbaneQLDAustralia,Centre for Molecular TherapeuticsAustralian Institute of Tropical Health & MedicineJames Cook UniversityCairnsQLDAustralia
| |
Collapse
|
22
|
Lei Y, Shen F, Zhu H, Zhu L, Chu R, Tang J, Yao W, Zhu G, Zhang D, Cao J, Cheng Y. Low genetic diversity and strong immunogenicity within the apical membrane antigen-1 of plasmodium ovale spp. imported from africa to china. Acta Trop 2020; 210:105591. [PMID: 32562621 PMCID: PMC7456792 DOI: 10.1016/j.actatropica.2020.105591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 10/27/2022]
Abstract
Malaria is still an important challenge for global public health because of its extensive mortality and morbidity. Plasmodium ovale is mainly distributed in tropical regions of Africa and Asia. it includes two distinct ovale malaria species, which are P. ovale curtisi and P. ovale wallikeri. Apical membrane antigen-1 (AMA-1) is an asexual blood-stage protein which is essential for Plasmodium. Thus far, no study on gene polymorphism and immunogenicity of P. ovale AMA-1 (PoAMA-1) has been conducted. Amplified poama1 gene products from 14 P ovale curtisi samples and 12 P ovale wallikeri samples imported from Africa to Jiangsu Province, China were sequenced and their polymorphisms were analyzed. We expressed recombinant PoAMA-1 (rPoAMA-1, 53 kDa) proteins in an E. coli expression system and evaluated immune responses against the rPoAMA-1 in BALB/c mice. We identified a synonymous mutation in nucleotide position 333 of the pocama-1 gene and powama-1 did not reveal any variation. The humoral and cellular immune responses to rPoAMA-1 were evaluated using enzyme-linked immunosorbent assay (ELISA) and flow cytometry. rPoAMA-1-immunized mice produced specific antibodies as verified by immunoblotting. The rPoAMA-1 induced high antibody titers (1: 640,000), and had high avidity indexes (an average of 78.63% and 83.40%). The antibodies also recognized the native proteins, namely, crude antigen from blood stages. Cross-reactivity between rPocAMA-1 and rPowAMA-1 was observed. Moreover, rPoAMA-1 s induced interferon (IFN)-gamma-secreting cells in mice and increased lymphocyte proliferation response. Low genetic diversity was observed in poama-1 from the Jiangsu Province imported malaria cases, and further studies conclusively showed its strong immunogenicity. Significant cross-reactivity was found between rPocAMA-1 and rPowAMA-1, suggesting that a single PoAMA-1 antigen could be used to diagnose P. ovale curtisi or P. ovale wallikeri patient simultaneously. However, further evaluation needs to be carried out to validate the potential and limitations of PoAMA-1 as a candidate vaccine.
Collapse
|
23
|
Yui K, Inoue SI. Host-pathogen interaction in the tissue environment during Plasmodium blood-stage infection. Parasite Immunol 2020; 43:e12763. [PMID: 32497249 DOI: 10.1111/pim.12763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/25/2020] [Accepted: 05/27/2020] [Indexed: 12/15/2022]
Abstract
Human malarial infection occurs after an infectious Anopheles mosquito bites. Following the initial liver-stage infection, parasites transform into merozoites, infecting red blood cells (RBCs). Repeated RBC infection then occurs during the blood-stage infection, while patients experience various malarial symptoms. Protective immune responses are elicited by this systemic infection, but excessive responses are sometimes harmful for hosts. As parasites infect only RBCs and their immediate precursors during this stage, direct parasite-host interactions occur primarily in the environment surrounded by endothelial lining of blood vessels. The spleen is the major organ where the immune system encounters infected RBCs, causing immunological responses. Its tissue structure is markedly altered during malarial infection in mice and humans. Plasmodium falciparum parasites inside RBCs express proteins, such as PfEMP-1 and RIFIN, transported to the RBC surfaces in order to evade immunological attack by sequestering themselves in the peripheral vasculature avoiding spleen or by direct immune cell inhibition through inhibitory receptors. Host cell production of regulatory cytokines IL-10 and IL-27 limits excessive immune responses, avoiding tissue damage. The regulation of the protective and inhibitory immune responses through host-parasite interactions allows chronic Plasmodium infection. In this review, we discuss underlying interaction mechanisms relevant for developing effective strategies against malaria.
Collapse
Affiliation(s)
- Katsuyuki Yui
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan.,Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Shin-Ichi Inoue
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| |
Collapse
|
24
|
Briquet S, Lawson-Hogban N, Peronet R, Mécheri S, Vaquero C. A genetically hmgb2 attenuated blood stage P. berghei induces crossed-long live protection. PLoS One 2020; 15:e0232183. [PMID: 32379764 PMCID: PMC7205229 DOI: 10.1371/journal.pone.0232183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/08/2020] [Indexed: 01/16/2023] Open
Abstract
Due to the lack of efficiency to control malaria elicited by sub-unit vaccine preparations, vaccination with live-attenuated Plasmodium parasite as reported 70 years ago with irradiated sporozoites regained recently a significant interest. The complex life cycle of the parasite and the different stages of development between mammal host and anopheles do not help to propose an easy vaccine strategy. In order to achieve a complete long-lasting protection against Plasmodium infection and disease, we considered a genetically attenuated blood stage parasite in the hmgb2 gene coding for the high-mobility-group-box 2 (HMGB2). This Plasmodium protein belongs to the HMGB family and hold as the mammal proteins, a double life since it acts first as a nuclear factor involved in chromatin remodelling and transcription regulation and second, when secreted as an active pro-inflammatory alarmin protein. Even though the number of reports on whole living attenuated blood stage parasites is limited when compared to attenuated sporozoites, the results reported with Plasmodium KO parasites are very encouraging. In this report, we present a novel strategy based on pre-immunization with Δhmgb2PbNK65 parasitized red blood cells that confer long-lasting protection in a murine experimental cerebral malaria model against two highly pathogenic homologous and heterologous parasites.
Collapse
Affiliation(s)
- Sylvie Briquet
- Sorbonne Université, Centre d’Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, France
- INSERM, U1135, CIMI-Paris, Paris, France
- CNRS, ERL 8255, CIMI-Paris, Paris, France
| | - Nadou Lawson-Hogban
- Sorbonne Université, Centre d’Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, France
- INSERM, U1135, CIMI-Paris, Paris, France
- CNRS, ERL 8255, CIMI-Paris, Paris, France
| | - Roger Peronet
- Unité de Biologie et Génétique du Paludisme, Institut Pasteur, Paris, France
- Centre National de Recherche Scientifique ou CNRS, Unité de Recherche Associée 2581, Paris, France
| | - Salaheddine Mécheri
- Unité de Biologie et Génétique du Paludisme, Institut Pasteur, Paris, France
- Centre National de Recherche Scientifique ou CNRS, Unité de Recherche Associée 2581, Paris, France
| | - Catherine Vaquero
- Sorbonne Université, Centre d’Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, France
- INSERM, U1135, CIMI-Paris, Paris, France
- CNRS, ERL 8255, CIMI-Paris, Paris, France
- * E-mail:
| |
Collapse
|
25
|
Adachi R, Tamura T. Plasmodium infection cure cycles induce modulation of conventional dendritic cells. Microbiol Immunol 2020; 64:377-386. [PMID: 32096562 DOI: 10.1111/1348-0421.12783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/20/2020] [Accepted: 02/23/2020] [Indexed: 01/01/2023]
Abstract
Malaria is one of the most widespread human infectious diseases worldwide and a cause of mortality. It is difficult to induce immunological memory against the malarial parasite Plasmodium. The immunity to clinical malaria disease is acquired with multiple infection and treatment cycles, along with substantial reduction in parasite burden. However, the mechanism of the acquired immunity remains largely unclear. Conventional DCs (cDCs) play a pivotal role in orchestration of immune responses. The purpose of this study is to analyze the characterization of cDCs after the infection and cure treatment cycles. Mice were infected with the lethal rodent malarial parasite Plasmodium berghei ANKA, which was followed by cure treatment with the antimalarial drug pyrimethamine. This was then followed by a challenge with live parasites. The mice that went through infection cure cycles showed significant immune response, demonstrating robust immunological memory against malaria parasites. We investigated the cytokine production capacity of splenic cDCs in both naive and infection cure mice by stimulating purified splenic cDCs with LPS (TLR4 agonist) or CpG (TLR9 agonist). The capacity of cytokine production was found to be significantly decreased in infection cure mice. The suppression of cytokine production was sustained for a long term (6 months). Moreover, the surface expression of MHC Class II molecules was significantly lower in infection cure mice than in naive mice. These results suggest that Plasmodium infection and cure treatment resulted in strong immunological memory and modulation of full functionality of cDCs.
Collapse
Affiliation(s)
- Ryosuke Adachi
- School of Pharmacy, Kanazawa University, Kanazawa, Japan
| | | |
Collapse
|
26
|
Human unconventional T cells in Plasmodium falciparum infection. Semin Immunopathol 2020; 42:265-277. [PMID: 32076813 PMCID: PMC7223888 DOI: 10.1007/s00281-020-00791-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 02/07/2020] [Indexed: 12/22/2022]
Abstract
Malaria is an old scourge of humankind and has a large negative impact on the economic development of affected communities. Recent success in malaria control and reduction of mortality seems to have stalled emphasizing that our current intervention tools need to be complemented by malaria vaccines. Different populations of unconventional T cells such as mucosal-associated invariant T (MAIT) cells, invariant natural killer T (iNKT) cells and γδ T cells are gaining attention in the field of malaria immunology. Significant advances in our basic understanding of unconventional T cell biology in rodent malaria models have been made, however, their roles in humans during malaria are less clear. Unconventional T cells are abundant in skin, gut and liver tissues, and long-lasting expansions and functional alterations were observed upon malaria infection in malaria naïve and malaria pre-exposed volunteers. Here, we review the current understanding of involvement of unconventional T cells in anti-Plasmodium falciparum immunity and highlight potential future research avenues.
Collapse
|
27
|
Gbedande K, Carpio VH, Stephens R. Using two phases of the CD4 T cell response to blood-stage murine malaria to understand regulation of systemic immunity and placental pathology in Plasmodium falciparum infection. Immunol Rev 2020; 293:88-114. [PMID: 31903675 PMCID: PMC7540220 DOI: 10.1111/imr.12835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/08/2019] [Accepted: 12/09/2019] [Indexed: 02/06/2023]
Abstract
Plasmodium falciparum infection and malaria remain a risk for millions of children and pregnant women. Here, we seek to integrate knowledge of mouse and human T helper cell (Th) responses to blood-stage Plasmodium infection to understand their contribution to protection and pathology. Although there is no complete Th subset differentiation, the adaptive response occurs in two phases in non-lethal rodent Plasmodium infection, coordinated by Th cells. In short, cellular immune responses limit the peak of parasitemia during the first phase; in the second phase, humoral immunity from T cell-dependent germinal centers is critical for complete clearance of rapidly changing parasite. A strong IFN-γ response kills parasite, but an excess of TNF compared with regulatory cytokines (IL-10, TGF-β) can cause immunopathology. This common pathway for pathology is associated with anemia, cerebral malaria, and placental malaria. These two phases can be used to both understand how the host responds to rapidly growing parasite and how it attempts to control immunopathology and variation. This dual nature of T cell immunity to Plasmodium is discussed, with particular reference to the protective nature of the continuous generation of effector T cells, and the unique contribution of effector memory T cells.
Collapse
Affiliation(s)
- Komi Gbedande
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Victor H Carpio
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
| | - Robin Stephens
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
| |
Collapse
|
28
|
[Development of malaria vaccines-state of the art]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2019; 63:45-55. [PMID: 31828371 PMCID: PMC7223738 DOI: 10.1007/s00103-019-03070-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Weltweit leben 3,1 Mrd. Menschen in Gebieten, in denen Malaria endemisch ist (Tropen, Subtropen). Jährlich erkranken etwa 200 Mio. Menschen, ca. 500.000 sterben daran. Betroffen sind vor allem Kinder. Um die Malaria zu kontrollieren und schlussendlich jegliche Neuinfektion zu verhindern, ist die Entwicklung wirksamer Impfstoffe von großer Bedeutung. In diesem Beitrag werden zunächst Hintergrundinformationen zur Geschichte der Impfstoffentwicklung, zur Malariaerkrankung und zu den Möglichkeiten der Therapie und Ausbreitungskontrolle gegeben. Der Hauptteil widmet sich dem aktuellen Forschungsstand zu Impfstoffen gegen den Erreger Plasmodium falciparum, gefolgt von einer ausführlichen Diskussion. Malaria ist eine parasitäre Infektionskrankheit, die von Einzellern, sog. Plasmodien, verursacht wird. Es werden 5 humanpathogene Spezies unterschieden, von denen P. falciparum über 99 % der Erkrankungen in Afrika verursacht. Überträger (Vektor) ist die Anophelesmücke. Plasmodium bietet innerhalb seines Lebenszyklus verschiedene Ansatzpunkte für die Wirkung von Impfstoffen. Von den insgesamt ca. 70 Impfstoffkandidaten sind die präerythrozytären Impfstoffe, die in den Leberzyklus des Parasiten eingreifen, aktuell am weitesten entwickelt. Die von der Weltgesundheitsorganisation (WHO) angestrebte Wirksamkeit von mindestens 75 % wurde aber längst nicht erreicht. Mit RTS,S/AS01 wird derzeit erstmals ein mäßig wirksamer Impfstoff großflächig eingesetzt. Schon jetzt ist offensichtlich, dass die Malaria nur im Zusammenspiel mit anderen Maßnahmen eingedämmt werden kann. Expositionsprophylaxe mit imprägnierten Moskitonetzen, der Einsatz von Insektiziden mit Residualeffekt in Innenräumen (Indoor Residual Spraying), die Vernichtung von Moskitobrutplätzen und schnelle Diagnose und Therapie der Erkrankung sind hier wichtige Elemente ebenso wie eine funktionierende Gesundheitsversorgung, die in den von Armut geprägten Gebieten oft nicht gewährleistet ist.
Collapse
|
29
|
Abstract
BACKGROUND Intermittent preventive treatment could help prevent malaria in infants (IPTi) living in areas of moderate to high malaria transmission in sub-Saharan Africa. The World Health Organization (WHO) policy recommended IPTi in 2010, but its adoption in countries has been limited. OBJECTIVES To evaluate the effects of intermittent preventive treatment (IPT) with antimalarial drugs to prevent malaria in infants living in malaria-endemic areas. SEARCH METHODS We searched the following sources up to 3 December 2018: the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library), MEDLINE (PubMed), Embase (OVID), LILACS (Bireme), and reference lists of articles. We also searched the metaRegister of Controlled Trials (mRCT) and the WHO International Clinical Trials Registry Platform (ICTRP) portal for ongoing trials up to 3 December 2018. SELECTION CRITERIA We included randomized controlled trials (RCTs) that compared IPT to placebo or no intervention in infants (defined as young children aged between 1 to 12 months) in malaria-endemic areas. DATA COLLECTION AND ANALYSIS The primary outcome was clinical malaria (fever plus asexual parasitaemia). Two review authors independently assessed trials for inclusion, evaluated the risk of bias, and extracted data. We summarized dichotomous outcomes and count data using risk ratios (RR) and rate ratios respectively, and presented all measures with 95% confidence intervals (CIs). We extracted protective efficacy values and their 95% CIs; when an included trial did not report this data, we calculated these values from the RR or rate ratio with its 95% CI. Where appropriate, we combined data in meta-analyses and assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS We included 12 trials that enrolled 19,098 infants; all were conducted in sub-Saharan Africa. Three trials were cluster-RCTs. IPTi with sulfadoxine-pyrimethamine (SP) was evaluated in 10 trials from 1999 to 2013 (n = 15,256). Trials evaluating ACTs included dihydroartemisinin-piperaquine (1 trial, 147 participants; year 2013), amodiaquine-artesunate (1 study, 684 participants; year 2008), and SP-artesunate (1 trial, 676 participants; year 2008). The earlier studies evaluated IPTi with SP, and were conducted in Tanzania (in 1999 and 2006), Mozambique (2004), Ghana (2004 to 2005), Gabon (2005), Kenya (2008), and Mali (2009). One trial evaluated IPTi with amodiaquine in Tanzania (2000). Later studies included three conducted in Kenya (2008), Tanzania (2008), and Uganda (2013), evaluating IPTi in multiple trial arms that included artemisinin-based combination therapy (ACT). Although the effect size varied over time and between drugs, overall IPTi impacts on the incidence of clinical malaria overall, with a 27% reduction (rate ratio 0.73, 0.65 to 0.82; 10 studies, 10,602 participants). The effect of SP appeared to attenuate over time, with trials conducted after 2009 showing little or no effect of the intervention. IPTi with SP probably resulted in fewer episodes of clinical malaria (rate ratio 0.79, 0.74 to 0.85; 8 trials, 8774 participants, moderate-certainty evidence), anaemia (rate ratio 0.82, 0.68 to 0.98; 6 trials, 7438 participants, moderate-certainty evidence), parasitaemia (rate ratio 0.66, 0.56 to 0.79; 1 trial, 1200 participants, moderate-certainty evidence), and fewer hospital admissions (rate ratio 0.85, 0.78 to 0.93; 7 trials, 7486 participants, moderate-certainty evidence). IPTi with SP probably made little or no difference to all-cause mortality (risk ratio 0.93, 0.74 to 1.15; 9 trials, 14,588 participants, moderate-certainty evidence). Since 2009, IPTi trials have evaluated ACTs and indicate impact on clinical malaria and parasitaemia. A small trial of DHAP in 2013 shows substantive effects on clinical malaria (RR 0.42, 0.33 to 0.54; 1 trial, 147 participants, moderate-certainty evidence) and parasitaemia (moderate-certainty evidence). AUTHORS' CONCLUSIONS In areas of sub-Saharan Africa, giving antimalarial drugs known to be effective against the malaria parasite at the time to infants as IPT probably reduces the risk of clinical malaria, anaemia, and hospital admission. Evidence from SP studies over a 19-year period shows declining efficacy, which may be due to increasing drug resistance. Combinations with ACTs appear promising as suitable alternatives for IPTi. 2 December 2019 Up to date All studies incorporated from most recent search All eligible published studies found in the last search (3 Dec, 2018) were included.
Collapse
Affiliation(s)
- Ekpereonne B Esu
- College of Medical Sciences, University of CalabarDepartment of Public HealthCalabarCross River StateNigeria
| | - Chioma Oringanje
- University of TucsonGIDP Entomology and Insect ScienceTucsonArizonaUSA85721
| | - Martin M Meremikwu
- University of Calabar Teaching HospitalDepartment of PaediatricsPMB 1115CalabarCross River StateNigeria
| | | |
Collapse
|
30
|
Cáceres Carrera L, Victoria C, Ramirez JL, Jackman C, Calzada JE, Torres R. Study of the epidemiological behavior of malaria in the Darien Region, Panama. 2015-2017. PLoS One 2019; 14:e0224508. [PMID: 31730618 PMCID: PMC6857920 DOI: 10.1371/journal.pone.0224508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/15/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Malaria is endemic in Darién and an assessment of the different factors affecting its epidemiology is crucial for the development of adequate strategies of surveillance, prevention, and disease control. The objective of this study was to determine the main characteristics of the epidemiological behavior of malaria in the Darien region. METHODS This research was comprised of a retrospective analysis to determine the incidence and malaria distribution in the Darien region from 2015 to 2017. We evaluated malaria indicators, disease distribution, incidence (by age group and sex), diagnostic methods, treatment, and control measures. In addition, we examined the cross-border migration activity and its possible contribution to the maintenance and distribution of malaria. RESULTS During the period of 2015-2017, we examined 41,141 thick blood smear samples, out of which 501 tested positive for malaria. Plasmodium vivax was responsible for 92.2% of those infections. Males comprised 62.7% of the total diagnosed cases. Meanwhile, a similar percentage, 62.7%, of the total cases were registered in economically active ages. The more frequent symptoms included fever (99.4%) and chills (97.4%), with 53.1% of cases registering between 2,000 and 6,000 parasites/μl of blood. The annual parasitic incidence (API) average was 3.0/1,000 inhabitants, while the slide positivity rate (SPR) was 1.2% and the annual blood examination rate (ABER) 22.5%. In Darién there is a constant internal and cross-border migration movement between Panama and Colombia. Malaria control measures consisted of the active and passive search of suspected cases and of the application of vector control measures. CONCLUSION This study provides an additional perspective on malaria epidemiology in Darién. Additional efforts are required to intensify malaria surveillance and to achieve an effective control, eventually moving closer to the objective of malaria elimination. At the same time, there is a need for more eco-epidemiological, entomological and migratory studies to determine how these factors contribute to the patterns of maintenance and dissemination of malaria.
Collapse
Affiliation(s)
- Lorenzo Cáceres Carrera
- Department of Medical Entomology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
- * E-mail:
| | | | - Jose L. Ramirez
- Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, Illinois, United States of America
| | - Carmela Jackman
- Epidemiology Department of the Darién Region, Ministry of Health, Panama City, Panama
| | - José E. Calzada
- Direcction of Research and Technological Development, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| | - Rolando Torres
- Department of Medical Entomology, Gorgas Memorial Institute of Health Studies, Panama City, Panama
| |
Collapse
|
31
|
Good MF, Stanisic DI. Whole parasite vaccines for the asexual blood stages ofPlasmodium. Immunol Rev 2019; 293:270-282. [DOI: 10.1111/imr.12819] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 08/27/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Michael F. Good
- Institute for Glycomics Griffith University Gold Coast Qld. Australia
| | | |
Collapse
|
32
|
Kumar R, Loughland JR, Ng SS, Boyle MJ, Engwerda CR. The regulation of CD4
+
T cells during malaria. Immunol Rev 2019; 293:70-87. [DOI: 10.1111/imr.12804] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 09/04/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Rajiv Kumar
- Centre of Experimental Medicine and Surgery Institute of Medical Sciences Banaras Hindu University Varanasi UP India
- Department of Medicine Institute of Medical Sciences Banaras Hindu University Varanasi UP India
| | - Jessica R. Loughland
- Human Malaria Immunology Laboratory QIMR Berghofer Medical Research Institute Brisbane Australia
| | - Susanna S. Ng
- Immunology and Infection Laboratory QIMR Berghofer Medical Research Institute Brisbane Australia
| | - Michelle J. Boyle
- Human Malaria Immunology Laboratory QIMR Berghofer Medical Research Institute Brisbane Australia
| | - Christian R. Engwerda
- Immunology and Infection Laboratory QIMR Berghofer Medical Research Institute Brisbane Australia
| |
Collapse
|
33
|
Odorizzi PM, Jagannathan P, McIntyre TI, Budker R, Prahl M, Auma A, Burt TD, Nankya F, Nalubega M, Sikyomu E, Musinguzi K, Naluwu K, Kakuru A, Dorsey G, Kamya MR, Feeney ME. In utero priming of highly functional effector T cell responses to human malaria. Sci Transl Med 2019; 10:10/463/eaat6176. [PMID: 30333241 DOI: 10.1126/scitranslmed.aat6176] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 05/10/2018] [Accepted: 09/17/2018] [Indexed: 12/14/2022]
Abstract
Malaria remains a significant cause of morbidity and mortality worldwide, particularly in infants and children. Some studies have reported that exposure to malaria antigens in utero results in the development of tolerance, which could contribute to poor immunity to malaria in early life. However, the effector T cell response to pathogen-derived antigens encountered in utero, including malaria, has not been well characterized. Here, we assessed the frequency, phenotype, and function of cord blood T cells from Ugandan infants born to mothers with and without placental malaria. We found that infants born to mothers with active placental malaria had elevated frequencies of proliferating effector memory fetal CD4+ T cells and higher frequencies of CD4+ and CD8+ T cells that produced inflammatory cytokines. Fetal CD4+ and CD8+ T cells from placental malaria-exposed infants exhibited greater in vitro proliferation to malaria antigens. Malaria-specific CD4+ T cell proliferation correlated with prospective protection from malaria during childhood. These data demonstrate that placental malaria is associated with the generation of proinflammatory malaria-responsive fetal T cells. These findings add to our current understanding of fetal immunity and indicate that a functional and protective pathogen-specific T cell response can be generated in utero.
Collapse
Affiliation(s)
- Pamela M Odorizzi
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, CA 94110 USA
| | | | - Tara I McIntyre
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, CA 94110 USA
| | - Rachel Budker
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, CA 94110 USA
| | - Mary Prahl
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Ann Auma
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Trevor D Burt
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94110, USA.,Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA
| | | | | | - Esther Sikyomu
- Infectious Disease Research Collaboration, Kampala, Uganda
| | | | - Kate Naluwu
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Abel Kakuru
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, CA 94110 USA
| | - Moses R Kamya
- School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Margaret E Feeney
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, San Francisco, CA 94110 USA. .,Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94110, USA
| |
Collapse
|
34
|
Dejon-Agobe JC, Ateba-Ngoa U, Lalremruata A, Homoet A, Engelhorn J, Nouatin OP, Edoa JR, Fernandes JF, Esen M, Mouwenda YD, Betouke Ongwe EM, Massinga-Loembe M, Hoffman SL, Sim BKL, Theisen M, Kremsner PG, Adegnika AA, Lell B, Mordmüller B. Controlled Human Malaria Infection of Healthy Adults With Lifelong Malaria Exposure to Assess Safety, Immunogenicity, and Efficacy of the Asexual Blood Stage Malaria Vaccine Candidate GMZ2. Clin Infect Dis 2019; 69:1377-1384. [PMID: 30561539 PMCID: PMC6763635 DOI: 10.1093/cid/ciy1087] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/18/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND GMZ2 is a recombinant malaria vaccine inducing immune responses against Plasmodium falciparum (Pf) merozoite surface protein-3 and glutamate-rich protein. We used standardized controlled human malaria infection (CHMI) to assess the efficacy of this asexual blood-stage vaccine. METHODS We vaccinated 50 healthy, adult volunteers with lifelong exposure to Pf 3 times, at 4-week intervals, with 30 or 100 µg GMZ2 formulated in CAF01, a liposome-based adjuvant; 100 µg GMZ2, formulated in Alhydrogel; or a control vaccine (Verorab). Approximately 13 weeks after the last vaccination, 35/50 volunteers underwent CHMI by direct venous inoculation of 3200 Pf sporozoites (Sanaria® PfSPZ Challenge). RESULTS Adverse events were similarly distributed between GMZ2 and control vaccinees. Baseline-corrected anti-GMZ2 antibody concentrations 4 weeks after the last vaccination were higher in all 3 GMZ2-vaccinated arms, compared to the control group. All GMZ2 formulations induced similar antibody levels. CHMI resulted in 29/34 (85%) volunteers with Pf parasitemia and 15/34 (44%) with malaria (parasitemia and symptoms). The proportion of participants with malaria (2/5 control, 6/10 GMZ2-Alhydrogel, 2/8 30 µg GMZ2-CAF01, and 5/11 100 µg GMZ2-CAF01) and the time it took them to develop malaria were similar in all groups. Baseline, vaccine-specific antibody concentrations were associated with protection against malaria. CONCLUSIONS GMZ2 is well tolerated and immunogenic in lifelong-Pf-exposed adults from Gabon, with similar antibody responses regardless of formulation. CHMI showed no protective effect of prior vaccination with GMZ2, although baseline, vaccine-specific antibody concentrations were associated with protection. CHMI with the PfSPZ Challenge is a potent new tool to validate asexual, blood-stage malaria vaccines in Africa. CLINICAL TRIALS REGISTRATION Pan-African Clinical Trials: PACTR201503001038304.
Collapse
Affiliation(s)
- Jean Claude Dejon-Agobe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Ulysse Ateba-Ngoa
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
- Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Albert Lalremruata
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Andreas Homoet
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Julie Engelhorn
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Odilon Paterne Nouatin
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Jean Ronald Edoa
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - José F Fernandes
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Meral Esen
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Yoanne Darelle Mouwenda
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Eunice M Betouke Ongwe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Marguerite Massinga-Loembe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | | | | | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Denmark
- Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Peter G Kremsner
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Ayôla A Adegnika
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
- Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| |
Collapse
|
35
|
Feeney ME. The immune response to malaria in utero. Immunol Rev 2019; 293:216-229. [PMID: 31553066 DOI: 10.1111/imr.12806] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/03/2019] [Indexed: 12/13/2022]
Abstract
Malaria causes tremendous early childhood morbidity and mortality, providing an urgent impetus for the development of a vaccine that is effective in neonates. However, the infant immune response to malaria may be influenced by events that occur well before birth. Placental malaria infection complicates one quarter of all pregnancies in Africa and frequently results in exposure of the fetus to malaria antigens in utero, while the immune system is still developing. Some data suggest that in utero exposure to malaria may induce immunologic tolerance that interferes with the development of protective immunity during childhood. More recently, however, a growing body of evidence suggests that fetal malaria exposure can prime highly functional malaria-specific T- and B-cells, which may contribute to postnatal protection from malaria. In utero exposure to malaria also impacts the activation and maturation of fetal antigen presenting cells and innate lymphocytes, which could have implications for global immunity in the infant. Here, we review recent advances in our understanding of how various components of the fetal immune system are altered by in utero exposure to malaria, discuss factors that may tilt the critical balance between tolerance and adaptive immunity, and consider the implications of these findings for malaria prevention strategies.
Collapse
Affiliation(s)
- Margaret E Feeney
- Departments of Pediatrics and Medicine, University of California, San Francisco, San Francisco, CA, USA
| |
Collapse
|
36
|
Dobaño C, Ubillos I, Jairoce C, Gyan B, Vidal M, Jiménez A, Santano R, Dosoo D, Nhabomba AJ, Ayestaran A, Aguilar R, Williams NA, Díez-Padrisa N, Lanar D, Chauhan V, Chitnis C, Dutta S, Gaur D, Angov E, Asante KP, Owusu-Agyei S, Valim C, Gamain B, Coppel RL, Cavanagh D, Beeson JG, Campo JJ, Moncunill G. RTS,S/AS01E immunization increases antibody responses to vaccine-unrelated Plasmodium falciparum antigens associated with protection against clinical malaria in African children: a case-control study. BMC Med 2019; 17:157. [PMID: 31409398 PMCID: PMC6693200 DOI: 10.1186/s12916-019-1378-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/27/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Vaccination and naturally acquired immunity against microbial pathogens may have complex interactions that influence disease outcomes. To date, only vaccine-specific immune responses have routinely been investigated in malaria vaccine trials conducted in endemic areas. We hypothesized that RTS,S/A01E immunization affects acquisition of antibodies to Plasmodium falciparum antigens not included in the vaccine and that such responses have an impact on overall malaria protective immunity. METHODS We evaluated IgM and IgG responses to 38 P. falciparum proteins putatively involved in naturally acquired immunity to malaria in 195 young children participating in a case-control study nested within the African phase 3 clinical trial of RTS,S/AS01E (MAL055 NCT00866619) in two sites of different transmission intensity (Kintampo high and Manhiça moderate/low). We measured antibody levels by quantitative suspension array technology and applied regression models, multimarker analysis, and machine learning techniques to analyze factors affecting their levels and correlates of protection. RESULTS RTS,S/AS01E immunization decreased antibody responses to parasite antigens considered as markers of exposure (MSP142, AMA1) and levels correlated with risk of clinical malaria over 1-year follow-up. In addition, we show for the first time that RTS,S vaccination increased IgG levels to a specific group of pre-erythrocytic and blood-stage antigens (MSP5, MSP1 block 2, RH4.2, EBA140, and SSP2/TRAP) which levels correlated with protection against clinical malaria (odds ratio [95% confidence interval] 0.53 [0.3-0.93], p = 0.03, for MSP1; 0.52 [0.26-0.98], p = 0.05, for SSP2) in multivariable logistic regression analyses. CONCLUSIONS Increased antibody responses to specific P. falciparum antigens in subjects immunized with this partially efficacious vaccine upon natural infection may contribute to overall protective immunity against malaria. Inclusion of such antigens in multivalent constructs could result in more efficacious second-generation multistage vaccines.
Collapse
Affiliation(s)
- Carlota Dobaño
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain. .,Centro de Investigação em Saúde de Manhiça (CISM), Rua 12, Cambeve, Vila de Manhiça, CP 1929, Maputo, Mozambique.
| | - Itziar Ubillos
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain
| | - Chenjerai Jairoce
- Centro de Investigação em Saúde de Manhiça (CISM), Rua 12, Cambeve, Vila de Manhiça, CP 1929, Maputo, Mozambique
| | - Ben Gyan
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.,Kintampo Health Research Centre, Kintampo, Ghana
| | - Marta Vidal
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain
| | - Alfons Jiménez
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain.,Spanish Consortium for Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Rebeca Santano
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain
| | - David Dosoo
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Augusto J Nhabomba
- Centro de Investigação em Saúde de Manhiça (CISM), Rua 12, Cambeve, Vila de Manhiça, CP 1929, Maputo, Mozambique
| | - Aintzane Ayestaran
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain
| | - Ruth Aguilar
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain
| | - Nana Aba Williams
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain
| | - Núria Díez-Padrisa
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain
| | - David Lanar
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Virander Chauhan
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Chetan Chitnis
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India.,Malaria Parasite Biology and Vaccines Unit, Institut Pasteur, Paris, France
| | - Sheetij Dutta
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Deepak Gaur
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India.,Laboratory of Malaria and Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Evelina Angov
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | | | - Seth Owusu-Agyei
- Kintampo Health Research Centre, Kintampo, Ghana.,Disease Control Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Clarissa Valim
- Department of Osteopathic Medical Specialties, Michigan State University, 909 Fee Road, Room B 309 West Fee Hall, East Lansing, MI, 48824, USA.,Department of Immunology and Infectious Diseases, Harvard T.H. Chen School of Public Health, 675 Huntington Ave., Boston, MA, 02115, USA
| | - Benoit Gamain
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge UMR_S1134, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Ross L Coppel
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, VIC, Australia
| | - David Cavanagh
- Institute of Immunology & Infection Research and Centre for Immunity, Infection & Evolution, Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, King's Buildings, Charlotte Auerbach Rd, Edinburgh, EH9 3FL, UK
| | - James G Beeson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - Joseph J Campo
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Rua 12, Cambeve, Vila de Manhiça, CP 1929, Maputo, Mozambique
| | - Gemma Moncunill
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Carrer Rosselló 153, E-08036, Barcelona, Catalonia, Spain. .,Centro de Investigação em Saúde de Manhiça (CISM), Rua 12, Cambeve, Vila de Manhiça, CP 1929, Maputo, Mozambique.
| |
Collapse
|
37
|
Cooper MM, Loiseau C, McCarthy JS, Doolan DL. Human challenge models: tools to accelerate the development of malaria vaccines. Expert Rev Vaccines 2019; 18:241-251. [PMID: 30732492 DOI: 10.1080/14760584.2019.1580577] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Malaria challenge models, where healthy human volunteers are intentionally infected with Plasmodium species parasites under controlled conditions, can be undertaken in several well-defined ways. These challenge models enable evaluation of the kinetics of parasite growth and clearance, host-pathogen interactions and the host immune response. They can facilitate discovery of candidate diagnostic biomarkers and novel vaccine targets. As translational tools they can facilitate testing of candidate vaccines and drugs and evaluation of diagnostic tests. AREAS COVERED Until recently, malaria human challenge models have been limited to only a few Plasmodium falciparum strains and used exclusively in malaria-naïve volunteers in non-endemic regions. Several recent advances include the use of alternate P. falciparum strains and other species of Plasmodia, as well as strains attenuated by chemical, radiation or genetic modification, and the conduct of studies in pre-exposed individuals. Herein, we discuss how this diversification is enabling more thorough vaccine efficacy testing and informing rational vaccine development. EXPERT OPINION The ability to comprehensively evaluate vaccine efficacy in controlled settings will continue to accelerate the translation of candidate malaria vaccines to the clinic, and inform the development and optimisation of potential vaccines that would be effective against multiple strains in geographically and demographically diverse settings.
Collapse
Affiliation(s)
- Martha M Cooper
- a Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine , James Cook University , Cairns , Australia
| | - Claire Loiseau
- a Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine , James Cook University , Cairns , Australia
| | - James S McCarthy
- b Infectious Diseases Programme , QIMR Berghofer Medical Research Institute , Brisbane , Australia
| | - Denise L Doolan
- a Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine , James Cook University , Cairns , Australia
| |
Collapse
|
38
|
Ssemaganda A, Giddam AK, Zaman M, Skwarczynski M, Toth I, Stanisic DI, Good MF. Induction of Plasmodium-Specific Immune Responses Using Liposome-Based Vaccines. Front Immunol 2019; 10:135. [PMID: 30774635 PMCID: PMC6367261 DOI: 10.3389/fimmu.2019.00135] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/16/2019] [Indexed: 12/30/2022] Open
Abstract
In the development of vaccines, the ability to initiate both innate and subsequent adaptive immune responses need to be considered. Live attenuated vaccines achieve this naturally, while inactivated and sub-unit vaccines generally require additional help provided through delivery systems and/or adjuvants. Liposomes present an attractive adjuvant/delivery system for antigens. Here, we review the key aspects of immunity against Plasmodium parasites, liposome design considerations and their current application in the development of a malaria vaccine.
Collapse
Affiliation(s)
| | | | - Mehfuz Zaman
- Institute for Glycomics, Griffith University, Southport, QLD, Australia
| | - Mariusz Skwarczynski
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | | | - Michael F. Good
- Institute for Glycomics, Griffith University, Southport, QLD, Australia
| |
Collapse
|
39
|
Wilson KL, Flanagan KL, Prakash MD, Plebanski M. Malaria vaccines in the eradication era: current status and future perspectives. Expert Rev Vaccines 2019; 18:133-151. [PMID: 30601095 DOI: 10.1080/14760584.2019.1561289] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The challenge to eradicate malaria is an enormous task that will not be achieved by current control measures, thus an efficacious and long-lasting malaria vaccine is required. The licensing of RTS, S/AS01 is a step forward in providing some protection, but a malaria vaccine that protects across multiple transmission seasons is still needed. To achieve this, inducing beneficial immune responses while minimising deleterious non-targeted effects will be essential. AREAS COVERED This article discusses the current challenges and advances in malaria vaccine development and reviews recent human clinical trials for each stage of infection. Pubmed and ScienceDirect were searched, focusing on cell mediated immunity and how T cell subsets might be targeted in future vaccines using novel adjuvants and emerging vaccine technologies. EXPERT COMMENTARY Despite decades of research there is no highly effective licensed malaria vaccine. However, there is cause for optimism as new adjuvants and vaccine systems emerge, and our understanding of correlates of protection increases, especially regarding cellular immunity. The new field of heterologous (non-specific) effects of vaccines also highlights the broader consequences of immunization. Importantly, the WHO led Malaria Vaccine Technology Roadmap illustrates that there is a political will among the global health community to make it happen.
Collapse
Affiliation(s)
- K L Wilson
- a Department of Immunology and Pathology, Faculty of Medicine, Nursing and Health Sciences , Monash University , Melbourne , Australia.,b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia
| | - K L Flanagan
- a Department of Immunology and Pathology, Faculty of Medicine, Nursing and Health Sciences , Monash University , Melbourne , Australia.,b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia.,c School of Medicine, Faculty of Health Sciences , University of Tasmania , Launceston , Australia
| | - M D Prakash
- b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia
| | - M Plebanski
- b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia
| |
Collapse
|
40
|
Manning JE, Cantaert T. Time to Micromanage the Pathogen-Host-Vector Interface: Considerations for Vaccine Development. Vaccines (Basel) 2019; 7:E10. [PMID: 30669682 PMCID: PMC6466432 DOI: 10.3390/vaccines7010010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/10/2019] [Accepted: 01/16/2019] [Indexed: 12/18/2022] Open
Abstract
The current increase in vector-borne disease worldwide necessitates novel approaches to vaccine development targeted to pathogens delivered by blood-feeding arthropod vectors into the host skin. A concept that is gaining traction in recent years is the contribution of the vector or vector-derived components, like salivary proteins, to host-pathogen interactions. Indeed, the triad of vector-host-pathogen interactions in the skin microenvironment can influence host innate and adaptive responses alike, providing an advantage to the pathogen to establish infection. A better understanding of this "bite site" microenvironment, along with how host and vector local microbiomes immunomodulate responses to pathogens, is required for future vaccines for vector-borne diseases. Microneedle administration of such vaccines may more closely mimic vector deposition of pathogen and saliva into the skin with the added benefit of near painless vaccine delivery. Focusing on the 'micro'⁻from microenvironments to microbiomes to microneedles⁻may yield an improved generation of vector-borne disease vaccines in today's increasingly complex world.
Collapse
Affiliation(s)
- Jessica E Manning
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Phnom Penh 12201, Cambodia.
| | - Tineke Cantaert
- Immunology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh 12201, Cambodia.
| |
Collapse
|
41
|
van den Hoogen LL, Walk J, Oulton T, Reuling IJ, Reiling L, Beeson JG, Coppel RL, Singh SK, Draper SJ, Bousema T, Drakeley C, Sauerwein R, Tetteh KKA. Antibody Responses to Antigenic Targets of Recent Exposure Are Associated With Low-Density Parasitemia in Controlled Human Plasmodium falciparum Infections. Front Microbiol 2019; 9:3300. [PMID: 30700984 PMCID: PMC6343524 DOI: 10.3389/fmicb.2018.03300] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 12/18/2018] [Indexed: 12/05/2022] Open
Abstract
The majority of malaria infections in low transmission settings remain undetectable by conventional diagnostics. A powerful model to identify antibody responses that allow accurate detection of recent exposure to low-density infections is controlled human malaria infection (CHMI) studies in which healthy volunteers are infected with the Plasmodium parasite. We aimed to evaluate antibody responses in malaria-naïve volunteers exposed to a single CHMI using a custom-made protein microarray. All participants developed a blood-stage infection with peak parasite densities up to 100 parasites/μl in the majority of participants (50/54), while the remaining four participants had peak densities between 100 and 200 parasites/μl. There was a strong correlation between parasite density and antibody responses associated with the most reactive blood-stage targets 1 month after CHMI (Etramp 5, GLURP-R2, MSP4 and MSP1-19; Spearman’s ρ = 0.82, p < 0.001). Most volunteers developed antibodies against a potential marker of recent exposure: Etramp 5 (37/45, 82%). Our findings justify validation in endemic populations to define a minimum set of antigens needed to detect exposure to natural low-density infections.
Collapse
Affiliation(s)
- Lotus L van den Hoogen
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Jona Walk
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Tate Oulton
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Isaie J Reuling
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia.,Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Ross L Coppel
- Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Susheel K Singh
- Department of Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Department of International Health, Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - Simon J Draper
- Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Kevin K A Tetteh
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, United Kingdom
| |
Collapse
|
42
|
Abstract
The blood stage of the malaria parasite life cycle is responsible for all the clinical symptoms of malaria. During the blood stage, Plasmodium merozoites invade and multiply within host red blood cells (RBCs). Here, we review the progress made, challenges faced, and new strategies available for the development of blood stage malaria vaccines. We discuss our current understanding of immune responses against blood stages and the status of clinical development of various blood stage malaria vaccine candidates. We then discuss possible paths forward to develop effective blood stage malaria vaccines. This includes a discussion of protective immune mechanisms that can be elicited to target blood stage parasites, novel delivery systems, immunoassays and animal models to optimize vaccine candidates in preclinical studies, and use of challenge models to get an early readout of vaccine efficacy.
Collapse
|
43
|
Controlled Infection Immunization Using Delayed Death Drug Treatment Elicits Protective Immune Responses to Blood-Stage Malaria Parasites. Infect Immun 2018; 87:IAI.00587-18. [PMID: 30323025 PMCID: PMC6300636 DOI: 10.1128/iai.00587-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/23/2018] [Indexed: 01/27/2023] Open
Abstract
Naturally acquired immunity to malaria is robust and protective against all strains of the same species of Plasmodium. This develops as a result of repeated natural infection, taking several years to develop. Naturally acquired immunity to malaria is robust and protective against all strains of the same species of Plasmodium. This develops as a result of repeated natural infection, taking several years to develop. Evidence suggests that apoptosis of immune lymphocytes due to uncontrolled parasite growth contributes to the slow acquisition of immunity. To hasten and augment the development of natural immunity, we studied controlled infection immunization (CII) using low-dose exposure to different parasite species (Plasmodium chabaudi, P. yoelii, or P. falciparum) in two rodent systems (BALB/c and C57BL/6 mice) and in human volunteers, with drug therapy commencing at the time of initiation of infection. CIIs with infected erythrocytes and in conjunction with doxycycline or azithromycin, which are delayed death drugs targeting the parasite’s apicoplast, allowed extended exposure to parasites at low levels. In turn, this induced strong protection against homologous challenge in all immunized mice. We show that P. chabaudi/P. yoelii infection initiated at the commencement of doxycycline therapy leads to cellular or antibody-mediated protective immune responses in mice, with a broad Th1 cytokine response providing the best correlate of protection against homologous and heterologous species of Plasmodium. P. falciparum CII with doxycycline was additionally tested in a pilot clinical study (n = 4) and was found to be well tolerated and immunogenic, with immunological studies primarily detecting increased cell-associated immune responses. Furthermore, we report that a single dose of the longer-acting drug, azithromycin, given to mice (n = 5) as a single subcutaneous treatment at the initiation of infection controlled P. yoelii infection and protected all mice against subsequent challenge.
Collapse
|
44
|
Frimpong A, Kusi KA, Ofori MF, Ndifon W. Novel Strategies for Malaria Vaccine Design. Front Immunol 2018; 9:2769. [PMID: 30555463 PMCID: PMC6281765 DOI: 10.3389/fimmu.2018.02769] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/12/2018] [Indexed: 12/19/2022] Open
Abstract
The quest for a licensed effective vaccine against malaria remains a global priority. Even though classical vaccine design strategies have been successful for some viral and bacterial pathogens, little success has been achieved for Plasmodium falciparum, which causes the deadliest form of malaria due to its diversity and ability to evade host immune responses. Nevertheless, recent advances in vaccinology through high throughput discovery of immune correlates of protection, lymphocyte repertoire sequencing and structural design of immunogens, provide a comprehensive approach to identifying and designing a highly efficacious vaccine for malaria. In this review, we discuss novel vaccine approaches that can be employed in malaria vaccine design.
Collapse
Affiliation(s)
- Augustina Frimpong
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana.,Immunology Department, College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.,African Institute for Mathematical Sciences, Cape Coast, Ghana
| | - Kwadwo Asamoah Kusi
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana.,Immunology Department, College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Michael Fokuo Ofori
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana.,Immunology Department, College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Wilfred Ndifon
- African Institute for Mathematical Sciences, Cape Coast, Ghana.,African Institute for Mathematical Sciences, University of Stellenbosch, Cape Town, South Africa
| |
Collapse
|
45
|
Stanisic DI, Fink J, Mayer J, Coghill S, Gore L, Liu XQ, El-Deeb I, Rodriguez IB, Powell J, Willemsen NM, De SL, Ho MF, Hoffman SL, Gerrard J, Good MF. Vaccination with chemically attenuated Plasmodium falciparum asexual blood-stage parasites induces parasite-specific cellular immune responses in malaria-naïve volunteers: a pilot study. BMC Med 2018; 16:184. [PMID: 30293531 PMCID: PMC6174572 DOI: 10.1186/s12916-018-1173-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/11/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The continuing morbidity and mortality associated with infection with malaria parasites highlights the urgent need for a vaccine. The efficacy of sub-unit vaccines tested in clinical trials in malaria-endemic areas has thus far been disappointing, sparking renewed interest in the whole parasite vaccine approach. We previously showed that a chemically attenuated whole parasite asexual blood-stage vaccine induced CD4+ T cell-dependent protection against challenge with homologous and heterologous parasites in rodent models of malaria. METHODS In this current study, we evaluated the immunogenicity and safety of chemically attenuated asexual blood-stage Plasmodium falciparum (Pf) parasites in eight malaria-naïve human volunteers. Study participants received a single dose of 3 × 107 Pf pRBC that had been treated in vitro with the cyclopropylpyrolloindole analogue, tafuramycin-A. RESULTS We demonstrate that Pf asexual blood-stage parasites that are completely attenuated are immunogenic, safe and well tolerated in malaria-naïve volunteers. Following vaccination with a single dose, species and strain transcending Plasmodium-specific T cell responses were induced in recipients. This included induction of Plasmodium-specific lymphoproliferative responses, T cells secreting the parasiticidal cytokines, IFN-γ and TNF, and CD3+CD45RO+ memory T cells. Pf-specific IgG was not detected. CONCLUSIONS This is the first clinical study evaluating a whole parasite blood-stage malaria vaccine. Following administration of a single dose of completely attenuated Pf asexual blood-stage parasites, Plasmodium-specific T cell responses were induced while Pf-specific antibodies were not detected. These results support further evaluation of this chemically attenuated vaccine in humans. TRIAL REGISTRATION Trial registration: ACTRN12614000228684 . Registered 4 March 2014.
Collapse
Affiliation(s)
- Danielle I Stanisic
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia.
| | - James Fink
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Johanna Mayer
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Sarah Coghill
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Letitia Gore
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Xue Q Liu
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Ibrahim El-Deeb
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Ingrid B Rodriguez
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Jessica Powell
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Nicole M Willemsen
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Sai Lata De
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Mei-Fong Ho
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | | | - John Gerrard
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Michael F Good
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia.
| |
Collapse
|
46
|
Pawliw R, Farrow R, Sekuloski S, Jennings H, Healer J, Phuong T, Sathe P, Pasay C, Evans K, Cowman AF, Schofield L, Chen N, McCarthy J, Trenholme K. A bioreactor system for the manufacture of a genetically modified Plasmodium falciparum blood stage malaria cell bank for use in a clinical trial. Malar J 2018; 17:283. [PMID: 30081913 PMCID: PMC6080485 DOI: 10.1186/s12936-018-2435-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 07/30/2018] [Indexed: 11/22/2022] Open
Abstract
Background Although the use of induced blood stage malaria infection has proven to be a valuable tool for testing the efficacy of vaccines and drugs against Plasmodium falciparum, a limiting factor has been the availability of Good Manufacturing Practice (GMP)—compliant defined P. falciparum strains for in vivo use. The aim of this study was to develop a cost-effective method for the large-scale production of P. falciparum cell banks suitable for use in clinical trials. Methods Genetically-attenuated parasites (GAP) were produced by targeted deletion of the gene encoding the knob associated histidine rich protein (kahrp) from P. falciparum strain 3D7. A GAP master cell bank (MCB) was manufactured by culturing parasites in an FDA approved single use, closed system sterile plastic bioreactor. All components used to manufacture the MCB were screened to comply with standards appropriate for in vivo use. The cryopreserved MCB was subjected to extensive testing to ensure GMP compliance for a phase 1 investigational product. Results Two hundred vials of the GAP MCB were successfully manufactured. At harvest, the GAP MCB had a parasitaemia of 6.3%, with 96% of parasites at ring stage. Testing confirmed that all release criteria were met (sterility, absence of viral contaminants and endotoxins, parasite viability following cryopreservation, identity and anti-malarial drug sensitivity of parasites). Conclusion Large-scale in vitro culture of P. falciparum parasites using a wave bioreactor can be achieved under GMP-compliant conditions. This provides a cost-effective methodology for the production of malaria parasites suitable for administration in clinical trials.
Collapse
Affiliation(s)
- Rebecca Pawliw
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia
| | - Rebecca Farrow
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia
| | - Silvana Sekuloski
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia
| | - Helen Jennings
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia
| | - Julie Healer
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Thuan Phuong
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia
| | - Pri Sathe
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Cielo Pasay
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia
| | - Krystal Evans
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Louis Schofield
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.,Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Nanhua Chen
- Department of Drug Resistance and Diagnostics, Australian Army Malaria Institute, Brisbane, Australia
| | - James McCarthy
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia.,School of Medicine, University of Queensland, Brisbane, Australia
| | - Katharine Trenholme
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Rd, Herston, Brisbane, QLD, Australia. .,School of Medicine, University of Queensland, Brisbane, Australia.
| |
Collapse
|
47
|
White SE, Harvey SA, Meza G, Llanos A, Guzman M, Gamboa D, Vinetz JM. Acceptability of a herd immunity-focused, transmission-blocking malaria vaccine in malaria-endemic communities in the Peruvian Amazon: an exploratory study. Malar J 2018; 17:179. [PMID: 29703192 PMCID: PMC5921293 DOI: 10.1186/s12936-018-2328-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/18/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND A transmission-blocking vaccine (TBV) to prevent malaria-infected humans from infecting mosquitoes has been increasingly considered as a tool for malaria control and elimination. This study tested the hypothesis that a malaria TBV would be acceptable among residents of a malaria-hypoendemic region. METHODS The study was carried out in six Spanish-speaking rural villages in the Department of Loreto in the Peruvian Amazon. These villages comprise a cohort of 430 households associated with the Peru-Brazil International Centre for Excellence in Malaria Research. Individuals from one-third (143) of enrolled households in an ongoing longitudinal, prospective cohort study in 6 communities in Loreto, Peru, were randomly selected to participate by answering a pre-validated questionnaire. RESULTS All 143 participants expressed desire for a malaria vaccine in general; only 1 (0.7%) expressed unwillingness to receive a transmission-blocking malaria vaccine. Injection was considered most acceptable for adults (97.2%); for children drops in the mouth were preferred (96.8%). Acceptability waned marginally with the prospect of multiple injections (83.8%) and different projected efficacies at 70 and 50% (90.1 and 71.8%, respectively). Respondents demonstrated clear understanding that the vaccine was for community, rather than personal, protection against malaria infection. DISCUSSION In this setting of the Peruvian Amazon, a transmission-blocking malaria vaccine was found to be almost universally acceptable. This study is the first to report that residents of a malaria-endemic region have been queried regarding a malaria vaccine strategy that policy-makers in the industrialized world often dismiss as altruistic.
Collapse
Affiliation(s)
- Sara E White
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego School of Medicine, 9500 Gilman Drive 0760, Biomedical Research Facility Room 4A16, La Jolla, CA, 92093-0760, USA
| | - Steven A Harvey
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St. E5030, Baltimore, MD, 21205, USA.
| | - Graciela Meza
- Facultad de Medicina Humana, Universidad Nacional de la Amazonia Peruana, Iquitos, Peru
| | - Alejandro Llanos
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Mitchel Guzman
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Dionicia Gamboa
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru.,Department of Cellular and Molecular Sciences, Faculty of Sciences and Laboratory of Research and Development, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M Vinetz
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego School of Medicine, 9500 Gilman Drive 0760, Biomedical Research Facility Room 4A16, La Jolla, CA, 92093-0760, USA. .,Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru. .,Department of Cellular and Molecular Sciences, Faculty of Sciences and Laboratory of Research and Development, Universidad Peruana Cayetano Heredia, Lima, Peru.
| |
Collapse
|
48
|
Reiman JM, Kumar S, Rodriguez IB, Gnidehou S, Ito K, Stanisic DI, Lee M, McPhun V, Majam V, Willemsen NM, Batzloff MR, Raja AI, Dooley B, Hoffman SL, Yanow SK, Good MF. Induction of immunity following vaccination with a chemically attenuated malaria vaccine correlates with persistent antigenic stimulation. Clin Transl Immunology 2018; 7:e1015. [PMID: 29670745 PMCID: PMC5894007 DOI: 10.1002/cti2.1015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 12/12/2022] Open
Abstract
Objectives Blood stage malaria parasites attenuated with seco-cyclopropyl pyrrolo indole (CPI) analogues induce robust immunity in mice to homologous and heterologous malaria parasites and are being considered for the development of a human vaccine. However, it is not understood how attenuated parasites induce immunity. We showed that following vaccination, parasite DNA persisted in blood for several months, raising the possibility that ongoing immune stimulation may be critical. However, parasites were not seen microscopically beyond 24 h postvaccination. We aimed to provide a mechanistic understanding of immune induction. Methods Mice were vaccinated with chemically attenuated Plasmodium chabaudi parasites. PCR and adoptive transfer studies were used to determine the presence of parasites and antigen in vivo. In other experiments, Plasmodium falciparum parasitised red blood cells were attenuated in vitro and RNA and antigen expression studied. Results We show that blood transferred from vaccinated mice into naïve mice activates T cells and induces complete protective immunity in the recipient mice strongly suggesting that there is persistence of parasite antigen postvaccination. This is supported by the presence of parasite RNA in vaccinated mice and both RNA and antigen expression in P. falciparum cultures treated with CPI drugs in vitro. In addition, drugs that block parasite growth also prevent the induction of immunity in vaccinated mice, indicating that some growth of attenuated parasites is required for immune induction. Conclusions Attenuated parasites persist at submicroscopic levels in the blood of mice postvaccination with the ability to activate T cells and induce ongoing protective immune responses.
Collapse
Affiliation(s)
- Jennifer M Reiman
- Institute for Glycomics Griffith University Gold Coast QLD Australia
| | - Sanjai Kumar
- Laboratory of Emerging Pathogens Division of Emerging and Transfusion Transmitted Diseases CBER, FDA Rockville MD USA
| | | | | | - Koichi Ito
- Institute for Glycomics Griffith University Gold Coast QLD Australia
| | | | - Moses Lee
- Georgia State University Atlanta GA USA
| | - Virginia McPhun
- Institute for Glycomics Griffith University Gold Coast QLD Australia
| | - Victoria Majam
- Laboratory of Emerging Pathogens Division of Emerging and Transfusion Transmitted Diseases CBER, FDA Rockville MD USA
| | | | | | - Amber I Raja
- Institute for Glycomics Griffith University Gold Coast QLD Australia
| | - Brad Dooley
- Institute for Glycomics Griffith University Gold Coast QLD Australia
| | | | | | - Michael F Good
- Institute for Glycomics Griffith University Gold Coast QLD Australia
| |
Collapse
|
49
|
Micro-epidemiology of mixed-species malaria infections in a rural population living in the Colombian Amazon region. Sci Rep 2018; 8:5543. [PMID: 29615693 PMCID: PMC5883018 DOI: 10.1038/s41598-018-23801-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/21/2018] [Indexed: 12/19/2022] Open
Abstract
Malaria outbreaks have been reported in recent years in the Colombian Amazon region, malaria has been re-emerging in areas where it was previously controlled. Information from malaria transmission networks and knowledge about the population characteristics influencing the dispersal of parasite species is limited. This study aimed to determine the distribution patterns of Plasmodium vivax, P. malariae and P. falciparum single and mixed infections, as well as the significant socio-spatial groupings relating to the appearance of such infections. An active search in 57 localities resulted in 2,106 symptomatic patients being enrolled. Parasitaemia levels were assessed by optical microscopy, and parasites were detected by PCR. The association between mixed infections (in 43.2% of the population) and socio-spatial factors was modelled using logistic regression and multiple correspondence analyses. P. vivax occurred most frequently (71.0%), followed by P. malariae (43.2%), in all localities. The results suggest that a parasite density-dependent regulation model (with fever playing a central role) was appropriate for modelling the frequency of mixed species infections in this population. This study highlights the under-reporting of Plasmodium spp. mixed infections in the malaria-endemic area of the Colombian Amazon region and the association between causative and environmental factors in such areas.
Collapse
|
50
|
Nlinwe ON, Kusi KA, Adu B, Sedegah M. T-cell responses against Malaria: Effect of parasite antigen diversity and relevance for vaccine development. Vaccine 2018; 36:2237-2242. [PMID: 29573877 DOI: 10.1016/j.vaccine.2018.03.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 01/21/2018] [Accepted: 03/07/2018] [Indexed: 11/24/2022]
Abstract
The on-going agenda for global malaria elimination will require the development of additional disease control and prevention measures since currently available tools are showing signs of inadequacy. Malaria vaccines are seen as one such important addition to the control arsenal since vaccines have proven to be highly effective public health tools against important human diseases. Both cell-mediated and antibody responses are generally believed to be important for malaria parasite control, although the exact targets of T and B cell responses against malaria have not been clearly defined. However, our current understanding of the immune response to malaria suggests that T cell responses against multiple antigenic targets may potentially be key for the development of a highly efficacious malaria vaccine. This review takes a comprehensive look at the available literature on T cell-mediated immunity against all human stages of the malaria parasite and the effect of antigen diversity on these responses. The implications of these interrelationships for the development of an effective vaccine for malaria are also highlighted.
Collapse
Affiliation(s)
- Omarine Nfor Nlinwe
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P.O. Box LG 581, Legon, Accra, Ghana.
| | - Kwadwo Asamoah Kusi
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P.O. Box LG 581, Legon, Accra, Ghana.
| | - Bright Adu
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, P.O. Box LG 581, Legon, Accra, Ghana.
| | - Martha Sedegah
- Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 209 l0-7500, USA.
| |
Collapse
|