1
|
Rajneesh, Tiwari R, Singh VK, Kumar A, Gupta RP, Singh AK, Gautam V, Kumar R. Advancements and Challenges in Developing Malaria Vaccines: Targeting Multiple Stages of the Parasite Life Cycle. ACS Infect Dis 2023; 9:1795-1814. [PMID: 37708228 DOI: 10.1021/acsinfecdis.3c00332] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Malaria, caused by Plasmodium species, remains a major global health concern, causing millions of deaths annually. While the introduction of the RTS,S vaccine has shown promise, there is a pressing need for more effective vaccines due to the emergence of drug-resistant parasites and insecticide-resistant vectors. However, the complex life cycle and genetic diversity of the parasite, technical obstacles, limited funding, and the impact of the 2019 pandemic have hindered progress in malaria vaccine development. This review focuses on advancements in malaria vaccine development, particularly the ongoing clinical trials targeting antigens from different stages of the Plasmodium life cycle. Additionally, we discuss the rationale, strategies, and challenges associated with vaccine design, aiming to enhance the immune response and protective efficacy of vaccine candidates. A cost-effective and multistage vaccine could hold the key to controlling and eradicating malaria.
Collapse
Affiliation(s)
- Rajneesh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Rahul Tiwari
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Vishal K Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Awnish Kumar
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Rohit P Gupta
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
- Department of Applied Microbiology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Akhilesh K Singh
- Faculty of Dental Science, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Vibhav Gautam
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Rajiv Kumar
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| |
Collapse
|
2
|
Friedman-Klabanoff DJ, Berry AA, Travassos MA, Cox C, Zhou Y, Mo AX, Nomicos EYH, Deye GA, Pasetti MF, Laurens MB. Low dose recombinant full-length circumsporozoite protein-based Plasmodium falciparum vaccine is well-tolerated and highly immunogenic in phase 1 first-in-human clinical testing. Vaccine 2021; 39:1195-1200. [PMID: 33494963 DOI: 10.1016/j.vaccine.2020.12.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/18/2020] [Accepted: 12/08/2020] [Indexed: 01/19/2023]
Abstract
Plasmodium falciparum circumsporozoite protein (CSP) is a major sporozoite surface protein and a key target of pre-erythrocytic malaria subunit vaccines. A full-length recombinant CSP (rCSP) based strategy could be advantageous, as this antigen includes a region critical to sporozoite cell attachment and hepatocyte invasion. The adjuvant Glucopyranosyl Lipid A-liposome Quillaja saponaria 21 (GLA-LSQ) functions as a TLR4 agonist, promotes antigen-specific TH1 responses and stimulates cytotoxic T cell production. To date, one study has reported the clinical acceptability of GLA-LSQ. We present interim results of a phase 1 first-in-human dose-escalation clinical trial of full-length rCSP vaccine given with or without GLA-LSQ adjuvant. Participants experienced only mild to moderate related solicited adverse events. The lowest adjuvanted vaccine dose achieved >90-fold rise in geometric mean anti-CSP IgG antibody titer. These favorable safety and immunogenicity results confirm the immunostimulatory capacity of this relatively new adjuvant and support next steps in clinical product development. Trial registration: ClinicalTrials.gov Identifier NCT03589794 (registered 18 July 2018).
Collapse
Affiliation(s)
- DeAnna J Friedman-Klabanoff
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrea A Berry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mark A Travassos
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | | | - Annie X Mo
- Parasitology and International Programs Branch, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Effie Y H Nomicos
- Parasitology and International Programs Branch, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Gregory A Deye
- Parasitology and International Programs Branch, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Marcela F Pasetti
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Matthew B Laurens
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
3
|
Ondigo BN, Hamre KES, Frosch AEP, Ayodo G, White MT, John CC. Antibody Profiles to P. falciparum Antigens Over Time Characterize Acute and Long-Term Malaria Exposure in an Area of Low and Unstable Transmission. Am J Trop Med Hyg 2020; 103:2189-2197. [PMID: 33124539 DOI: 10.4269/ajtmh.19-0480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Prevalence and levels of antibodies to multiple Plasmodium falciparum antigens show promise as tools for estimating malaria exposure. In a highland area of Kenya with unstable transmission, we assessed the presence and levels of antibodies to 12 pre-erythrocytic and blood-stage P. falciparum antigens by multiplex cytometric bead assay or ELISA in 604 individuals in August 2007, with follow-up testing in this cohort in April 2008, April 2009, and May 2010. Four hundred individuals were tested at all four time points. During this period, the only substantial malaria incidence occurred from April to August 2009. Antibody prevalence in adults was high at all time points (> 70%) for apical membrane antigen 1, erythrocyte-binding antigen 175, erythrocyte-binding protein-2, glutamate rich protein (GLURP)-R2, merozoite surface protein (MSP) 1 (19), MSP-1 (42), and liver-stage antigen-1; moderate (30-70%) for GLURP-R0, MSP-3, and thrombospondin-related adhesive protein; and low (< 30%) for SE and circumsporozoite protein (CSP). Changes in community-wide malaria exposure were best reflected in decreasing antibody levels overtime for highly immunogenic antigens, and in antibody seroprevalence overtime for the less-immunogenic antigens. Over the 3 years, antibody levels to all antigens except CSP and schizont extract (SE) decreased in an age-dependent manner. Prevalence and levels of antibodies to all antigens except CSP and SE increased with age. Increases in antibody prevalence and levels to CSP and SE coincided with increases in community-wide malaria incidence. Antibody levels to multiple P. falciparum antigens decrease in the absence of consistent transmission. Multiplex assays that assess both the presence and level of antibodies to multiple pre-erythrocytic and blood-stage P. falciparum antigens may provide the most useful estimates of past and recent malaria transmission in areas of unstable transmission and could be useful tools in malaria control and elimination campaigns.
Collapse
Affiliation(s)
- Bartholomew N Ondigo
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), Bethesda, Maryland.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
| | - Karen E S Hamre
- CDC Foundation, Atlanta, Georgia.,Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota.,Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Anne E P Frosch
- Hennepin Healthcare Research Institute, Minneapolis, Minnesota.,Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - George Ayodo
- School of Health Sciences, Jaramogi Oginga Odinga University of Science and Technology, Siaya, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Michael T White
- Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Chandy C John
- Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Ryan White Center for Pediatric Infectious Diseases and Global Health, Indiana University School of Medicine, Indianapolis, Indiana
| |
Collapse
|
4
|
Hamre KES, Ayodo G, Hodges JS, John CC. A Mass Insecticide-Treated Bed Net Distribution Campaign Reduced Malaria Risk on an Individual but Not Population Level in a Highland Epidemic-Prone Area of Kenya. Am J Trop Med Hyg 2020; 103:2183-2188. [PMID: 33146104 DOI: 10.4269/ajtmh.19-0306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In epidemic-prone areas of the western highlands, the Kenya Ministry of Health conducted campaigns of indoor residual spraying (IRS) of households, followed by mass distribution of insecticide-treated bed nets (ITNs), as part of the National Malaria Strategy. We previously reported that in the highland areas of Kipsamoite and Kapsisiywa, widespread IRS coverage in 2007, after lower but substantial coverage in 2005 and 2006, contributed to possible local interruption of malaria transmission between 2007 and 2008. Indoor residual spraying campaigns in the area ended in 2010, succeeded by a mass ITN distribution campaign in 2011 and 2012 targeting universal coverage. Insecticide-treated bed net use in the area increased from 17.1% pre-campaign in 2011 to 51.7% post-campaign in 2012, but decreased to 35.8% in 2013. The ITN campaign did not reduce malaria incidence in the population as a whole (odds ratio [OR] after ITN distribution versus before, 1.29, 95% CI: 1.00-1.66, P = 0.049). However, in 2011-2013, individuals who stated that they slept under ITNs as compared with those who did not had a decrease in malaria incidence that approached statistical significance (OR 0.74, 95% CI: 0.52-1.04, P = 0.08). Mass ITN distribution after previous annual IRS campaigns was insufficient to further reduce malaria transmission in this area of low and highly seasonal transmission possibly because of low ITN use despite the mass campaign.
Collapse
Affiliation(s)
- Karen E S Hamre
- CDC Foundation, Atlanta, Georgia.,Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota.,Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - George Ayodo
- Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - James S Hodges
- Division of Biostatistics, University of Minnesota, Minneapolis, Minnesota
| | - Chandy C John
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota.,Department of Pediatrics, Indiana University, Indianapolis, Indiana
| |
Collapse
|
5
|
Matos ADS, Rodrigues-da-Silva RN, Soares IF, Baptista BDO, de Souza RM, Bitencourt-Chaves L, Totino PRR, Sánchez-Arcila JC, Daniel-Ribeiro CT, López-Camacho C, Reyes-Sandoval A, Pratt-Riccio LR, Lima-Junior JDC. Antibody Responses Against Plasmodium vivax TRAP Recombinant and Synthetic Antigens in Naturally Exposed Individuals From the Brazilian Amazon. Front Immunol 2019; 10:2230. [PMID: 31620136 PMCID: PMC6763564 DOI: 10.3389/fimmu.2019.02230] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/03/2019] [Indexed: 11/13/2022] Open
Abstract
Thrombospondin-related adhesive protein (TRAP) is essential for sporozoite motility and the invasion of mosquitoes' salivary gland and vertebrate's hepatocyte and is, thus, considered a promising pre-erythrocytic vaccine candidate. Despite the existence of a few reports on naturally acquired immune response against Plasmodium vivax TRAP (PvTRAP), it has never been explored so far in the Amazon region, so results are conflicting. Here, we characterized the (IgG and IgG subclass) antibody reactivity against recombinant PvTRAP in a cross-sectional study of 299 individuals exposed to malaria infection in three municipalities (Cruzeiro do Sul, Mâncio Lima and Guajará) from the Acre state of the Brazilian Amazon. In addition, the full PvTRAP sequence was screened for B-cell epitopes using in silico and in vitro approaches. Firstly, we confirmed that PvTRAP is naturally immunogenic in the cohort population since 49% of the individuals were IgG-responders to it. The observed immune responses were mainly driven by cytophilic IgG1 over all other sublcasses and the IgG levels that was corelated with age and time of residence in the studied area (p < 0.05). Interestingly, only the levels of specific anti-TRAP IgG3 seemed to be associated with protection, as IgG3 responders presented a significantly higher time elapse since the last malaria episode than those recorded for IgG3 non-responders. Regarding the B-cell epitope mapping, among the 148 responders to PvTRAP, four predicted epitopes were confirmed by recognition of antibodies (PvTRAPR197-H227; PvTRAPE237-T258; PvTRAPP344-G374; and PvTRAPE439-K454). Nevertheless, the frequency of responders against these peptides were low and did not show a clear correlation with the antibody response against the corresponding antigen. Moreover, none of the linear confirmed epitopes were located in the binding regions of PvTRAP in respect to the host cell ligand. Collectively, our data confirm the PvTRAP immunogenicity among Amazon inhabitants, while suggesting that the main important B-cell epitopes are not linear.
Collapse
Affiliation(s)
- Ada da Silva Matos
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | | | | | | | | | - Lana Bitencourt-Chaves
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | | | - Juan Camilo Sánchez-Arcila
- Viral Immunology Laboratory, Oswaldo Cruz Institute, IOC, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | | | - César López-Camacho
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Arturo Reyes-Sandoval
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | |
Collapse
|
6
|
Odhiambo EO, Datta D, Guyah B, Ayodo G, Ondigo BN, Abong'o BO, John CC, Frosch AEP. HIV infection drives IgM and IgG3 subclass bias in Plasmodium falciparum-specific and total immunoglobulin concentration in Western Kenya. Malar J 2019; 18:297. [PMID: 31470903 PMCID: PMC6716850 DOI: 10.1186/s12936-019-2915-7] [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: 02/22/2019] [Accepted: 08/17/2019] [Indexed: 11/22/2022] Open
Abstract
Background HIV infection is associated with more frequent and severe episodes of malaria and may be the result of altered malaria-specific B cell responses. However, it is poorly understood how HIV and the associated lymphopenia and immune activation affect malaria-specific antibody responses. Methods HIV infected and uninfected adults were recruited from Bondo subcounty hospital in Western Kenya at the time of HIV testing (antiretroviral and co-trimoxazole prophylaxis naïve). Total and Plasmodium falciparum apical membrane antigen-1 (AMA1) and glutamate rich protein-R0 (GLURP-R0) specific IgM, IgG and IgG subclass concentrations was measured in 129 and 52 of recruited HIV-infected and uninfected individuals, respectively. In addition, HIV-1 viral load (VL), CD4+ T cell count, and C-reactive protein (CRP) concentration was quantified in study participants. Antibody levels were compared based on HIV status and the associations of antibody concentration with HIV-1 VL, CD4+ count, and CRP levels was measured using Spearman correlation testing. Results Among study participants, concentrations of IgM, IgG1 and IgG3 antibodies to AMA1 and GLURP-R0 were higher in HIV infected individuals compared to uninfected individuals (all p < 0.001). The IgG3 to IgG1 ratio to both AMA1 and GLURP-R0 was also significantly higher in HIV-infected individuals (p = 0.02). In HIV-infected participants, HIV-1 VL and CRP were weakly correlated with AMA1 and GLURP-R0 specific IgM and IgG1 concentrations and total (not antigen specific) IgM, IgG, IgG1, and IgG3 concentrations (all p < 0.05), suggesting that these changes are related in part to viral load and inflammation. Conclusions Overall, HIV infection leads to a total and malaria antigen-specific immunoglobulin production bias towards higher levels of IgM, IgG1, and IgG3, and HIV-1 viraemia and systemic inflammation are weakly correlated with these changes. Further assessments of antibody affinity and function and correlation with risk of clinical malaria, will help to better define the effects of HIV infection on clinical and biological immunity to malaria.
Collapse
Affiliation(s)
- Eliud O Odhiambo
- Department of Biomedical Science and Technology, Maseno University, Maseno, Kenya.,Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Department of Pediatrics, Indiana University School of Medicine, Indianapolis, USA
| | - Dibyadyuti Datta
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, USA
| | - Bernard Guyah
- Department of Biomedical Science and Technology, Maseno University, Maseno, Kenya
| | - George Ayodo
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | - Bartholomew N Ondigo
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya.,Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Disease, NIH, Bethesda, MD, USA
| | - Benard O Abong'o
- Department of Biomedical Science and Technology, Maseno University, Maseno, Kenya.,Department of Biology, Faculty of Science and Technology, National University of Lesotho, Roma, Lesotho
| | - Chandy C John
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Department of Pediatrics, Indiana University School of Medicine, Indianapolis, USA
| | - Anne E P Frosch
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya. .,Department of Medicine, University of Minnesota, Minneapolis, USA. .,Hennepin Healthcare Research Institute, Minneapolis, MN, USA.
| |
Collapse
|
7
|
Mosquito Bite-Induced Controlled Human Malaria Infection with Plasmodium vivax or P. falciparum Generates Immune Responses to Homologous and Heterologous Preerythrocytic and Erythrocytic Antigens. Infect Immun 2019; 87:IAI.00541-18. [PMID: 30559218 DOI: 10.1128/iai.00541-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 12/07/2018] [Indexed: 11/20/2022] Open
Abstract
Seroepidemiological studies on the prevalence of antibodies to malaria antigens are primarily conducted on individuals from regions of endemicity. It is therefore difficult to accurately correlate the antibody responses to the timing and number of prior malaria infections. This study was undertaken to assess the evolution of antibodies to the dominant surface antigens of Plasmodium vivax and P. falciparum following controlled human malaria infection (CHMI) in malaria-naive individuals. Serum samples from malaria-naive adults, collected before and after CHMI with either P. vivax (n = 18) or P. falciparum (n = 18), were tested for the presence of antibodies to the circumsporozoite protein (CSP) and the 42-kDa fragment of merozoite surface protein 1 (MSP-142) of P. vivax and P. falciparum using an enzyme-linked immunosorbent assay (ELISA). Approximately 1 month following CHMI with either P. vivax or P. falciparum, >60% of subjects seroconverted to homologous CSP and MSP-1. More than 50% of the subjects demonstrated reactivity to heterologous CSP and MSP-142, and a similar proportion of subjects remained seropositive to homologous MSP-142 >5 months after CHMI. Computational analysis provides insight into the presence of cross-reactive responses. The presence of long-lived and heterologous reactivity and its functional significance, if any, need to be taken into account while evaluating malaria exposure in field settings.
Collapse
|
8
|
Pirahmadi S, Zakeri S, Mehrizi AA, Karimi L, Djadid ND. Heterogeneity in the acquisition of naturally acquired antibodies to cell-traversal protein for ookinetes and sporozoites (CelTOS) and thrombospondin-related adhesion protein (TRAP) of Plasmodium falciparum in naturally infected patients from unstable malaria areas in Iran. Acta Trop 2019; 190:365-374. [PMID: 30543766 DOI: 10.1016/j.actatropica.2018.12.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 12/07/2018] [Accepted: 12/08/2018] [Indexed: 11/19/2022]
Abstract
Currently, there is no subunit malaria vaccine capable of providing long-lasting protection, and a vaccine based on a single-antigen has shown moderate to unsatisfactory efficacies in clinical trials. As in malaria elimination and eradication strategies, the primary objective is reduction in disease and death due to P. falciparum, in the present investigation, for the first time, we attempted to determine and compare the naturally acquired immune responses to two well-recognized sporozoite antigens, cell-traversal protein for ookinetes and sporozoites (CelTOS) and thrombospondin-related adhesion protein (TRAP), in P. falciparum-infected individuals (n = 204) in low malaria transmission settings of Iran using ELISA. Besides, the profile of IgG isotype responses, the avidity of IgG, IgG1, and IgG3, and the association of anti-PfCelTOS and -PfTRAP antibodies with host age were evaluated. Positive antibody responses to PfCelTOS and PfTRAP antigens were detected in 16.2% and 31.9% of Iranian P. falciparum-infected individuals, respectively, indicating significantly lower immune response to PfCelTOS than PfTRAP (P <0.0001, McNemar's test). Also, among the positive samples for anti-PfCelTOS (n = 33) and -PfTRAP (n = 65) total IgG, the cytophilic IgG1 and IgG3 antibodies were predominant. A significant proportion of the examined positive responders had high- and intermediate-avidity for IgG (93.9%, 87.7%), IgG1 (96.3%, 87.7%), and IgG3 (76%, 78.7%) antibodies to both PfCelTOS and PfTRAP antigens, respectively, with no correlation with age (P >0.05; Spearman's correlation test). In conclusion, the present data suggests the acquisition of heterogenic immune responses to both antigens in the same patients naturally infected with P. falciparum from settings of low malaria transmission intensity in Iran in which their role in protection to malaria needs further study.
Collapse
Affiliation(s)
- Sakineh Pirahmadi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran.
| | - Akram Abouie Mehrizi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Leila Karimi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Navid Dinparast Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| |
Collapse
|
9
|
Dewasurendra RL, Jeffreys A, Gunawardena SA, Chandrasekharan NV, Rockett K, Kwiatkowski D, Karunaweera ND. Host genetic polymorphisms and serological response against malaria in a selected population in Sri Lanka. Malar J 2018; 17:473. [PMID: 30558622 PMCID: PMC6296029 DOI: 10.1186/s12936-018-2622-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 12/11/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Antibodies against the merozoite surface protein 1-19 (MSP1-19) and the apical membrane antigen 1 (AMA1) of the malaria parasite (Plasmodium vivax) are proven to be important in protection against clinical disease. Differences in the production/maintenance of antibodies may be due to many factors including host genetics. This paper discusses the association of 4 anti-malarial antibodies with selected host genetic markers. METHODS Blood was collected from individuals (n = 242) with a history of malaria within past 15 years for DNA and serum. ELISA was carried out for serum to determine the concentration of anti-malarial antibodies MSP1-19 and AMA1 for both vivax and falciparum malaria. 170 SNPs related to malaria were genotyped. Associations between seropositivity, antibody levels and genetic, non-genetic factors were determined. RESULTS Age ranged 13-74 years (mean age = 40.21 years). Majority were females. Over 90% individuals possessed either one or more type(s) of anti-malarial antibodies. Five SNPs were significantly associated with seropositivity. One SNP was associated with MSP1-19_Pv(rs739718); 4 SNPs with MSP1-19_Pf (rs6874639, rs2706379, rs2706381 and rs2075820) and1 with AMA1_Pv (rs2075820). Eleven and 7 genotypes (out of 15) were significantly associated with either presence or absence of antibodies. Three SNPs were found to be significantly associated with the antibody levels viz. rs17411697 with MSP1-19_Pv, rs2227491 with AMA1_Pv and rs229587 with AMA1_Pf. Linkage of the markers in the two groups was similar, but lower LOD scores were observed in seropositives compared to seronegatives. DISCUSSION AND CONCLUSIONS The study suggests that several SNPs in the human genome that exist in Sri Lankan populations are significantly associated with anti-malarial antibodies, either with generation and/or maintenance of antibodies for longer periods, which can be due to either individual polymorphisms or most probably a combined effect of the markers.
Collapse
Affiliation(s)
- Rajika L Dewasurendra
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo 8, Sri Lanka
| | - Anna Jeffreys
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Sharmini A Gunawardena
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo 8, Sri Lanka
| | | | - Kirk Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Nadira D Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Kynsey Road, Colombo 8, Sri Lanka.
| |
Collapse
|
10
|
Abagna HB, Acquah FK, Okonu R, Aryee NA, Theisen M, Amoah LE. Assessment of the quality and quantity of naturally induced antibody responses to EBA175RIII-V in Ghanaian children living in two communities with varying malaria transmission patterns. Malar J 2018; 17:14. [PMID: 29310662 PMCID: PMC5759240 DOI: 10.1186/s12936-017-2167-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/29/2017] [Indexed: 01/26/2023] Open
Abstract
Background Recent global reports on malaria suggest significant decrease in disease severity and an increase in control interventions in many malaria endemic countries, including Ghana. However, a major driving force sustaining malaria transmission in recent times is the asymptomatic carriage of malaria parasites, which can enhance immune responses against parasite antigens. This study determined the prevalence and relative avidities of naturally induced antibodies to EBA175RIII–VLl in asymptomatic children living in two communities with varying malaria transmission patterns. Methods An asexual stage Plasmodium falciparum antigen, EBA175RIII–VLl was expressed in Lactococcus lactis, purified and used in indirect ELISA to measure total and cytophilic IgG concentrations and avidities in children aged between 6 and 12 years. The children were selected from Obom and Abura, communities with perennial and seasonal malaria transmission, respectively. Venous blood samples were collected in July and October 2015 and again in January 2016. The multiplicity of infection and the genetic diversity of EBA175RIII circulating in both sites were also assessed using polymerase chain reaction. Results Asymptomatic parasite carriage in the children from Obom decreased from July (peak season), through October and January, however parasite carriage in children from Abura was bimodal, with the lowest prevalence estimated in October. Antibody concentrations over the course of the study remained stable within each study site however, children living in Obom had significantly higher EBA175RIII–VLl antibody concentrations than children living in Abura (P < 0.05, Mann–Whitney test). Over the course of the study, the relative antibody avidities of EBA175RIII–VLl IgG antibodies were similar within and between the sites. Conclusion Naturally acquired IgG concentrations but not relative antibody avidities to EBA175RIII–V were significantly higher in Obom where malaria transmission is perennial than in Abura, where malaria transmission is seasonal. Electronic supplementary material The online version of this article (10.1186/s12936-017-2167-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Hamza B Abagna
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.,Department of Medical Biochemistry, University of Ghana, Accra, Ghana
| | - Festus K Acquah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Ruth Okonu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Nii A Aryee
- Department of Medical Biochemistry, University of Ghana, Accra, Ghana
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Linda E Amoah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| |
Collapse
|
11
|
Nazeri S, Zakeri S, Mehrizi AA, Djadid ND. Naturally acquired immune responses to thrombospondin-related adhesion protein (TRAP) of Plasmodium vivax in patients from areas of unstable malaria transmission. Acta Trop 2017; 173:45-54. [PMID: 28549910 DOI: 10.1016/j.actatropica.2017.05.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/20/2017] [Accepted: 05/20/2017] [Indexed: 10/19/2022]
Abstract
A key tool for the control, elimination, and eradication of Plasmodium vivax is the development of an effective vaccine. The thrombospondin-related adhesion protein (TRAP) is one of the major sporozoite antigens that plays an important role in the invasion of mosquito salivary glands and hepatocytes by sporozoites. The main goal of this study was to evaluate the naturally acquired antibodies to the P. vivax TRAP (PvTRAP) in patients from malaria-endemic areas of Iran (n=116), Afghanistan (n=50), and Pakistan (n=50). The PvTRAP gene was expressed in Escherichia coli Rosetta (DE3)-pET23a and used as antigen in enzyme-linked immunosorbent assay (ELISA). The profile of immunoglobulin G (IgG) isotype and the avidity of IgG, IgG1, and IgG3 to PvTRAP, as well as the association between anti-PvTRAP isotype responses and host age were evaluated. Only 42.24% of Iranian, 38% of Afghani, and 44% of Pakistani patients infected with P. vivax had positive anti-PvTRAP IgG, and the prevalence of responders in the three countries did not differ significantly (P>0.05). Moreover, the prevalence of IgG1 and IgG3 antibody responses to PvTRAP showed no significant correlation with age (P>0.05). Individuals exposed to vivax malaria in the unstable malaria transmission areas are able to produce antibodies to the TRAP antigen at all ages in response to P. vivax infections. Finally, the presence of mature IgG1 and IgG3 antibodies with high to intermediate avidity against PvTRAP antigen (>60%) provide more information to understand the interactions between the host and P. vivax parasite. In summary, the present study provides data that support the rational development of an effective pre-erythrocytic stage vaccine based on PvTRAP antigen.
Collapse
|
12
|
Nash SD, Prevots DR, Kabyemela E, Khasa YP, Lee KL, Fried M, Duffy PE. A Malaria-Resistant Phenotype with Immunological Correlates in a Tanzanian Birth Cohort Exposed to Intense Malaria Transmission. Am J Trop Med Hyg 2017; 96:1190-1196. [PMID: 28500801 DOI: 10.4269/ajtmh.16-0554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
AbstractMalaria incidence is highly heterogeneous even in areas of high transmission, although no conclusive evidence exists that innate or naturally acquired resistance can prevent infection over an extended period of time. This longitudinal study examined immunoparasitological evidence for a malaria-resistant phenotype in which children do not develop malaria despite an extended period of exposure to parasites. Within a birth cohort followed from 2002 to 2006 in Muheza, Tanzania, an area of intense transmission, children (N = 687) provided blood smears biweekly during infancy and monthly thereafter. Maternal and childhood characteristics were obtained, cord-blood cytokines were measured, and antibody responses were assayed as measures of stage-specific exposure. Sixty-three (9.2%) children had no blood smear-positive slides over 2 years of follow-up (range: 1-3.5 years) and were identified as malaria resistant. Malaria-resistant children were similar to other children with respect to completeness of follow-up and all maternal and childhood characteristics except residence area. Antibody seroprevalence was similar for two sporozoite antigens, but malaria-resistant children had a lower antibody seroprevalence to merozoite antigens merozoite surface protein 1 (5.4% versus 30.2%; P < 0.0001) and apical membrane antigen 1 (7.2% versus 33.3%; P < 0.0001). Malaria-resistant children had higher cytokine levels in cord blood, particularly interleukin-1β. In summary, a subset of children living in an area of intense transmission was exposed to malaria parasites, but never developed patent parasitemia; this phenotype was associated with a distinct cytokine profile at birth and antibody profile during infancy. Further research with malaria-resistant children may identify mechanisms for naturally acquired immunity.
Collapse
Affiliation(s)
- Scott D Nash
- Epidemiology Unit, Laboratory of Clinical Infectious Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - D Rebecca Prevots
- Epidemiology Unit, Laboratory of Clinical Infectious Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | | | - Yogender P Khasa
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Kun-Lin Lee
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| |
Collapse
|
13
|
McCallum FJ, Persson KEM, Fowkes FJI, Reiling L, Mugyenyi CK, Richards JS, Simpson JA, Williams TN, Gilson PR, Hodder AN, Sanders PR, Anders RF, Narum DL, Chitnis C, Crabb BS, Marsh K, Beeson JG. Differing rates of antibody acquisition to merozoite antigens in malaria: implications for immunity and surveillance. J Leukoc Biol 2017; 101:913-925. [PMID: 27837017 PMCID: PMC5346181 DOI: 10.1189/jlb.5ma0716-294r] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 09/28/2016] [Accepted: 10/19/2016] [Indexed: 12/18/2022] Open
Abstract
Antibodies play a key role in acquired human immunity to Plasmodium falciparum (Pf) malaria and target merozoites to reduce or prevent blood-stage replication and the development of disease. Merozoites present a complex array of antigens to the immune system, and currently, there is only a partial understanding of the targets of protective antibodies and how responses to different antigens are acquired and boosted. We hypothesized that there would be differences in the rate of acquisition of antibodies to different antigens and how well they are boosted by infection, which impacts the acquisition of immunity. We examined responses to a range of merozoite antigens in 2 different cohorts of children and adults with different age structures and levels of malaria exposure. Overall, antibodies were associated with age, exposure, and active infection, and the repertoire of responses increased with age and active infection. However, rates of antibody acquisition varied between antigens and different regions within an antigen following exposure to malaria, supporting our hypothesis. Antigen-specific responses could be broadly classified into early response types in which antibodies were acquired early in childhood exposure and late response types that appear to require substantially more exposure for the development of substantial levels. We identified antigen-specific responses that were effectively boosted after recent infection, whereas other responses were not. These findings advance our understanding of the acquisition of human immunity to malaria and are relevant to the development of malaria vaccines targeting merozoite antigens and the selection of antigens for use in malaria surveillance.
Collapse
Affiliation(s)
- Fiona J McCallum
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
- Department of Drug Evaluation, Australian Army Malaria Institute, Brisbane, Australia
| | - Kristina E M Persson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Freya J I Fowkes
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Victoria, Australia
- Departments of Epidemiology and Preventive Medicine and Infectious Diseases, Monash University, Melbourne, Australia
| | - Linda Reiling
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Cleopatra K Mugyenyi
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Jack S Richards
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- Department of Microbiology, Monash University, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Victoria, Australia
| | - Thomas N Williams
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Medicine, Imperial College of Science, Technology and Medicine, London, United Kingdom
| | - Paul R Gilson
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Anthony N Hodder
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Paul R Sanders
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Robin F Anders
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Latrobe University, Melbourne, Australia
| | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Brendan S Crabb
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Kevin Marsh
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | - James G Beeson
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia;
- Department of Microbiology, Monash University, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
| |
Collapse
|
14
|
Ravenhall M, Benavente ED, Mipando M, Jensen ATR, Sutherland CJ, Roper C, Sepúlveda N, Kwiatkowski DP, Montgomery J, Phiri KS, Terlouw A, Craig A, Campino S, Ocholla H, Clark TG. Characterizing the impact of sustained sulfadoxine/pyrimethamine use upon the Plasmodium falciparum population in Malawi. Malar J 2016; 15:575. [PMID: 27899115 PMCID: PMC5129638 DOI: 10.1186/s12936-016-1634-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/23/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malawi experienced prolonged use of sulfadoxine/pyrimethamine (SP) as the front-line anti-malarial drug, with early replacement of chloroquine and delayed introduction of artemisinin-based combination therapy. Extended use of SP, and its continued application in pregnancy is impacting the genomic variation of the Plasmodium falciparum population. METHODS Whole genome sequence data of P. falciparum isolates covering 2 years of transmission within Malawi, alongside global datasets, were used. More than 745,000 SNPs were identified, and differences in allele frequencies between countries assessed, as well as genetic regions under positive selection determined. RESULTS Positive selection signals were identified within dhps, dhfr and gch1, all components of the parasite folate pathway associated with SP resistance. Sitting predominantly on a dhfr triple mutation background, a novel copy number increase of ~twofold was identified in the gch1 promoter. This copy number was almost fixed (96.8% frequency) in Malawi samples, but found at less than 45% frequency in other African populations, and distinct from a whole gene duplication previously reported in Southeast Asian parasites. CONCLUSIONS SP resistance selection pressures have been retained in the Malawian population, with known resistance dhfr mutations at fixation, complemented by a novel gch1 promoter duplication. The effects of the duplication on the fitness costs of SP variants and resistance need to be elucidated.
Collapse
Affiliation(s)
- Matt Ravenhall
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Mwapatsa Mipando
- Department of Physiology, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Anja T. R. Jensen
- Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - Colin J. Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Cally Roper
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Nuno Sepúlveda
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Centre for Statistics and Applications of University of Lisbon, Lisbon, Portugal
| | | | - Jacqui Montgomery
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Kamija S. Phiri
- School of Public Health and Family Medicine, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Anja Terlouw
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Alister Craig
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Harold Ocholla
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- School of Public Health and Family Medicine, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Taane G. Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| |
Collapse
|
15
|
Wang Q, Zhao Z, Zhang X, Li X, Zhu M, Li P, Yang Z, Wang Y, Yan G, Shang H, Cao Y, Fan Q, Cui L. Naturally Acquired Antibody Responses to Plasmodium vivax and Plasmodium falciparum Merozoite Surface Protein 1 (MSP1) C-Terminal 19 kDa Domains in an Area of Unstable Malaria Transmission in Southeast Asia. PLoS One 2016; 11:e0151900. [PMID: 26999435 PMCID: PMC4801383 DOI: 10.1371/journal.pone.0151900] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 02/29/2016] [Indexed: 12/24/2022] Open
Abstract
Understanding naturally acquired immunity to infections caused by Plasmodia in different malaria endemicity settings is needed for better vaccine designs and for exploring antibody responses as a proxy marker of malaria transmission intensity. This study investigated the sero-epidemiology of malaria along the international border between China and Myanmar, where malaria elimination action plans are in place. This study recruited 233 P. vivax and 156 P. falciparum infected subjects with acute malaria at the malaria clinics and hospitals. In addition, 93 and 67 healthy individuals from the same endemic region or from non-endemic region, respectively, were used as controls. Acute malaria infections were identified by microscopy. Anti-recombinant PfMSP119 and PvMSP119 antibody levels were measured by ELISA. Antibody responses to respective MSP119 were detected in 50.9% and 78.2% patients with acute P. vivax and P. falciparum infections, respectively. There were cross-reacting antibodies in Plasmodium patients against these two recombinant proteins, though we could not exclude the possibility of submicroscopic mixed-species infections. IgG1, IgG3 and IgG4 were the major subclasses. Interestingly, 43.2% of the healthy endemic population also had antibodies against PfMSP119, whereas only 3.9% of this population had antibodies against PvMSP119. Higher antibody levels were correlated with age and parasite density, but not with season, gender or malaria history. Both total IgG and individual IgG subclasses underwent substantial declines during the convalescent period in three months. This study demonstrated that individuals in a hypoendemic area with coexistence of P. vivax and P. falciparum can mount rapid antibody responses against both PfMSP119 and PvMSP119. The significantly higher proportion of responders to PfMSP119 in the healthy endemic population indicates higher prevalence of P. falciparum in the recent past. Specific antibodies against PvMSP119 could serve as a marker of recent exposure to P. vivax in epidemiological studies.
Collapse
MESH Headings
- Acute Disease
- Adolescent
- Amino Acid Sequence
- Antibodies, Protozoan/immunology
- Antibody Formation/immunology
- Asia, Southeastern/epidemiology
- Child
- Child, Preschool
- Demography
- Follow-Up Studies
- Humans
- Immunoglobulin G/immunology
- Infant
- Logistic Models
- Malaria, Falciparum/blood
- Malaria, Falciparum/immunology
- Malaria, Falciparum/parasitology
- Malaria, Falciparum/transmission
- Malaria, Vivax/blood
- Malaria, Vivax/immunology
- Malaria, Vivax/parasitology
- Malaria, Vivax/transmission
- Merozoite Surface Protein 1/chemistry
- Merozoite Surface Protein 1/immunology
- Molecular Weight
- Plasmodium falciparum/immunology
- Plasmodium vivax/immunology
- Protein Structure, Tertiary
- Recombinant Proteins/immunology
Collapse
Affiliation(s)
- Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Xuexing Zhang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Xuelian Li
- Department of Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning, China
| | - Min Zhu
- School of Humanities and Social Science, China Medical University, Shenyang, Liaoning, China
| | - Peipei Li
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Ying Wang
- Institute of Tropical Medicine, Third Military Medical University, Chongqing, China
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, CA, United States of America
| | - Hong Shang
- Department of Laboratory Medicine, the First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
- * E-mail: (YC); (QF); (LC)
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
- * E-mail: (YC); (QF); (LC)
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA, 16802, United States of America
- * E-mail: (YC); (QF); (LC)
| |
Collapse
|
16
|
A Venue-Based Survey of Malaria, Anemia and Mobility Patterns among Migrant Farm Workers in Amhara Region, Ethiopia. PLoS One 2015; 10:e0143829. [PMID: 26619114 PMCID: PMC4664424 DOI: 10.1371/journal.pone.0143829] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/10/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mobile populations present unique challenges to malaria control and elimination efforts. Each year, a large number of individuals travel to northwest Amhara Region, Ethiopia to seek seasonal employment on large-scale farms. Agricultural areas typically report the heaviest malaria burden within Amhara thereby placing migrants at high risk of infection. Yet little is known about these seasonal migrants and their malaria-related risk factors. METHODS AND FINDINGS In July 2013, a venue-based survey of 605 migrant laborers 18 years or older was conducted in two districts of North Gondar zone, Amhara. The study population was predominantly male (97.7%) and young (mean age 22.8 years). Plasmodium prevalence by rapid diagnostic test (RDT) was 12.0%; One quarter (28.3%) of individuals were anemic (hemoglobin <13 g/dl). Nearly all participants (95.6%) originated from within Amhara Region, with half (51.6%) coming from within North Gondar zone. Around half (51.2%) slept in temporary shelters, while 20.5% regularly slept outside. Only 11.9% of participants had access to a long lasting insecticidal net (LLIN). Reported net use the previous night was 8.8% overall but 74.6% among those with LLIN access. Nearly one-third (30.1%) reported having fever within the past two weeks, of whom 31.3% sought care. Cost and distance were the main reported barriers to seeking care. LLIN access (odds ratio [OR] = 0.30, P = 0.04) and malaria knowledge (OR = 0.50, P = 0.02) were significantly associated with reduced Plasmodium infection among migrants, with a similar but non-significant trend observed for reported net use the previous night (OR = 0.16, P = 0.14). CONCLUSIONS High prevalence of malaria and anemia were observed among a young population that originated from relatively proximate areas. Low access to care and low IRS and LLIN coverage likely place migrant workers at significant risk of malaria in this area and their return home may facilitate parasite transport to other areas. Strategies specifically tailored to migrant farm workers are needed to support malaria control and elimination activities in Ethiopia.
Collapse
|
17
|
Helb DA, Tetteh KKA, Felgner PL, Skinner J, Hubbard A, Arinaitwe E, Mayanja-Kizza H, Ssewanyana I, Kamya MR, Beeson JG, Tappero J, Smith DL, Crompton PD, Rosenthal PJ, Dorsey G, Drakeley CJ, Greenhouse B. Novel serologic biomarkers provide accurate estimates of recent Plasmodium falciparum exposure for individuals and communities. Proc Natl Acad Sci U S A 2015; 112:E4438-47. [PMID: 26216993 PMCID: PMC4538641 DOI: 10.1073/pnas.1501705112] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Tools to reliably measure Plasmodium falciparum (Pf) exposure in individuals and communities are needed to guide and evaluate malaria control interventions. Serologic assays can potentially produce precise exposure estimates at low cost; however, current approaches based on responses to a few characterized antigens are not designed to estimate exposure in individuals. Pf-specific antibody responses differ by antigen, suggesting that selection of antigens with defined kinetic profiles will improve estimates of Pf exposure. To identify novel serologic biomarkers of malaria exposure, we evaluated responses to 856 Pf antigens by protein microarray in 186 Ugandan children, for whom detailed Pf exposure data were available. Using data-adaptive statistical methods, we identified combinations of antibody responses that maximized information on an individual's recent exposure. Responses to three novel Pf antigens accurately classified whether an individual had been infected within the last 30, 90, or 365 d (cross-validated area under the curve = 0.86-0.93), whereas responses to six antigens accurately estimated an individual's malaria incidence in the prior year. Cross-validated incidence predictions for individuals in different communities provided accurate stratification of exposure between populations and suggest that precise estimates of community exposure can be obtained from sampling a small subset of that community. In addition, serologic incidence predictions from cross-sectional samples characterized heterogeneity within a community similarly to 1 y of continuous passive surveillance. Development of simple ELISA-based assays derived from the successful selection strategy outlined here offers the potential to generate rich epidemiologic surveillance data that will be widely accessible to malaria control programs.
Collapse
Affiliation(s)
- Danica A Helb
- Department of Medicine, University of California, San Francisco, CA 94110; Division of Infectious Diseases, School of Public Health, University of California, Berkeley, CA 94720; Global Health Group, University of California, San Francisco, CA 94158
| | - Kevin K A Tetteh
- Department Immunology and Infection, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Philip L Felgner
- Division of Infectious Diseases, Department of Medicine, University of California, Irvine, CA 92697
| | - Jeff Skinner
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852
| | - Alan Hubbard
- Division of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720
| | | | - Harriet Mayanja-Kizza
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | | | - Moses R Kamya
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - James G Beeson
- Center for Biomedical Research, Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Canada 3004
| | - Jordan Tappero
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333
| | - David L Smith
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom; Sanaria Institute for Global Health and Tropical Medicine, Rockville, MD 20850
| | - Peter D Crompton
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852
| | - Philip J Rosenthal
- Department of Medicine, University of California, San Francisco, CA 94110
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, CA 94110
| | - Christopher J Drakeley
- Department Immunology and Infection, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Bryan Greenhouse
- Department of Medicine, University of California, San Francisco, CA 94110;
| |
Collapse
|
18
|
Noland GS, Jansen P, Vulule JM, Park GS, Ondigo BN, Kazura JW, Moormann AM, John CC. Effect of transmission intensity and age on subclass antibody responses to Plasmodium falciparum pre-erythrocytic and blood-stage antigens. Acta Trop 2015; 142:47-56. [PMID: 25446174 DOI: 10.1016/j.actatropica.2014.10.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 08/27/2014] [Accepted: 10/15/2014] [Indexed: 10/24/2022]
Abstract
Cytophilic immunoglobulin (IgG) subclass responses (IgG1 and IgG3) to Plasmodium falciparum antigens have been associated with protection from malaria, yet the relative importance of transmission intensity and age in generation of subclass responses to pre-erythrocytic and blood-stage antigens have not been clearly defined. We analyzed IgG subclass responses to the pre-erythrocytic antigens CSP, LSA-1, and TRAP and the blood-stage antigens AMA-1, EBA-175, and MSP-1 in asymptomatic residents age 2 years or older in stable (n=116) and unstable (n=96) transmission areas in Western Kenya. In the area of stable malaria transmission, a high prevalence of cytophilic (IgG1 and IgG3) antibodies to each antigen was seen in all age groups. Prevalence and levels of cytophilic antibodies to pre-erythrocytic and blood-stage P. falciparum antigens increased with age in the unstable transmission area, yet IgG1 and IgG3 responses to most antigens for all ages in the unstable transmission area were less prevalent and lower in magnitude than even the youngest age group from the stable transmission area. The dominance of cytophilic responses over non-cytophilic (IgG2 and IgG4) was more pronounced in the stable transmission area, and the ratio of IgG3 over IgG1 generally increased with age. In the unstable transmission area, the ratio of cytophilic to non-cytophilic antibodies did not increase with age, and tended to be IgG3-biased for pre-erythrocytic antigens yet IgG1-biased for blood-stage antigens. The differences between areas could not be attributed to active parasitemia status, as there were minimal differences in antibody responses between those positive and negative for Plasmodium infection by microscopy in the stable transmission area. Individuals in areas of unstable transmission have low cytophilic to non-cytophilic IgG subclass ratios and low IgG3:IgG1 ratios to P. falciparum antigens. These imbalances could contribute to the persistent risk of clinical malaria in these areas and serve as population-level, age-specific biomarkers of transmission.
Collapse
|
19
|
Elliott SR, Fowkes FJ, Richards JS, Reiling L, Drew DR, Beeson JG. Research priorities for the development and implementation of serological tools for malaria surveillance. F1000PRIME REPORTS 2014; 6:100. [PMID: 25580254 PMCID: PMC4229730 DOI: 10.12703/p6-100] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Surveillance is a key component of control and elimination programs. Malaria surveillance has been typically reliant on case reporting by health services, entomological estimates and parasitemia (Plasmodium species) point prevalence. However, these techniques become less sensitive and relatively costly as transmission declines. There is great potential for the development and application of serological biomarkers of malaria exposure as sero-surveillance tools to strengthen malaria control and elimination. Antibodies to malaria antigens are sensitive biomarkers of population-level malaria exposure and can be used to identify hotspots of malaria transmission, estimate transmission levels, monitor changes over time or the impact of interventions on transmission, confirm malaria elimination, and monitor re-emergence of malaria. Sero-surveillance tools could be used in reference laboratories or developed as simple point-of-care tests for community-based surveillance, and different applications and target populations dictate the technical performance required from assays that are determined by properties of antigens and antibody responses. To advance the development of sero-surveillance tools for malaria elimination, major gaps in our knowledge need to be addressed through further research. These include greater knowledge of potential antigens, the sensitivity and specificity of antibody responses, and the longevity of these responses and defining antigens and antibodies that differentiate between exposure to Plasmodium falciparum and P. vivax. Additionally, a better understanding of the influence of host factors, such as age, genetics, and comorbidities on antibody responses in different populations is needed.
Collapse
Affiliation(s)
| | - Freya J.I. Fowkes
- Burnet Institute85 Commercial Road, Melbourne, Victoria 3004Australia
- School of Epidemiology and Preventive Medicine, Monash University99 Commercial Road, Victoria 3004Australia
- School of Population Health and Department of Medicine (RMH), University of MelbourneVictoria 3010Australia
| | - Jack S. Richards
- Burnet Institute85 Commercial Road, Melbourne, Victoria 3004Australia
- School of Population Health and Department of Medicine (RMH), University of MelbourneVictoria 3010Australia
- Department of Microbiology, Monash UniversityVictoria 3800Australia
| | - Linda Reiling
- Burnet Institute85 Commercial Road, Melbourne, Victoria 3004Australia
| | - Damien R. Drew
- Burnet Institute85 Commercial Road, Melbourne, Victoria 3004Australia
| | - James G. Beeson
- Burnet Institute85 Commercial Road, Melbourne, Victoria 3004Australia
- School of Population Health and Department of Medicine (RMH), University of MelbourneVictoria 3010Australia
- Department of Microbiology, Monash UniversityVictoria 3800Australia
| |
Collapse
|
20
|
Ondigo BN, Hodges JS, Ireland KF, Magak NG, Lanar DE, Dutta S, Narum DL, Park GS, Ofulla AV, John CC. Estimation of recent and long-term malaria transmission in a population by antibody testing to multiple Plasmodium falciparum antigens. J Infect Dis 2014; 210:1123-32. [PMID: 24737801 DOI: 10.1093/infdis/jiu225] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Tools that estimate recent and long-term malaria transmission in a population would be highly useful for malaria elimination programs. METHODS The prevalence of antibodies to 11 Plasmodium falciparum antigens was assessed by cytometric bead assay or enzyme-linked immunosorbent assay in 1000 people in a highland area of Kenya over 14 months, during a period of interrupted malaria transmission. RESULTS Antibodies differed by antigen in acquisition with age: rapid (>80% antibody positive by age 20 years, 5 antigens), moderate (>40% positive by age 20 years, 3 antigens), or slow (<40% positive by age 20 years, 3 antigens). Antibody seroreversion rates in the 14 months between samples decreased with age rapidly (7 antigens), slowly (3 antigens), or remained high at all ages (schizont extract). Estimated antibody half-lives in individuals >10 years of age were long (40 to >80 years) for 5 antigens, moderate (5-20 years) for 3 antigens, and short (<1 year) for 3 antigens. CONCLUSIONS Antibodies to P. falciparum antigens in malaria-endemic areas vary by age, antigen, and time since last exposure to P. falciparum. Multiplex P. falciparum antibody testing could provide estimates of long-term and recent malaria transmission and potentially of a population's susceptibility to future clinical malaria.
Collapse
Affiliation(s)
- Bartholomew N Ondigo
- Department of Biomedical Science and Technology, Maseno University Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - James S Hodges
- Division of Biostatistics, School of Public Health, University of Minnesota
| | | | | | - David E Lanar
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Sheetij Dutta
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - David L Narum
- Malaria Vaccine Branch, Walter Reed Army Institute for Research, Silver Spring
| | - Gregory S Park
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute of Health, Rockville, Maryland
| | - Ayub V Ofulla
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute of Health, Rockville, Maryland
| | - Chandy C John
- Department of Pediatrics, University of Minnesota Medical School Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| |
Collapse
|
21
|
Baum E, Badu K, Molina DM, Liang X, Felgner PL, Yan G. Protein microarray analysis of antibody responses to Plasmodium falciparum in western Kenyan highland sites with differing transmission levels. PLoS One 2013; 8:e82246. [PMID: 24312649 PMCID: PMC3846730 DOI: 10.1371/journal.pone.0082246] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/22/2013] [Indexed: 01/01/2023] Open
Abstract
Malaria represents a major public health problem in Africa. In the East African highlands, the high-altitude areas were previously considered too cold to support vector population and parasite transmission, rendering the region particularly prone to epidemic malaria due to the lack of protective immunity of the population. Since the 1980’s, frequent malaria epidemics have been reported and these successive outbreaks may have generated some immunity against Plasmodium falciparum amongst the highland residents. Serological studies reveal indirect evidence of human exposure to the parasite, and can reliably assess prevalence of exposure and transmission intensity in an endemic area. However, the vast majority of serological studies of malaria have been, hereto, limited to a small number of the parasite’s antigens. We surveyed and compared the antibody response profiles of age-stratified sera from residents of two endemic areas in the western Kenyan highlands with differing malaria transmission intensities, during two distinct seasons, against 854 polypeptides of P. falciparum using high-throughput proteomic microarray technology. We identified 107 proteins as serum antibody targets, which were then characterized for their gene ontology biological process and cellular component of the parasite, and showed significant enrichment for categories related to immune evasion, pathogenesis and expression on the host’s cell and parasite’s surface. Additionally, we calculated age-fitted annual seroconversion rates for the immunogenic proteins, and contrasted the age-dependent antibody acquisition for those antigens between the two sampling sites. We observed highly immunogenic antigens that produce stable antibody responses from early age in both sites, as well as less immunogenic proteins that require repeated exposure for stable responses to develop and produce different seroconversion rates between sites. We propose that a combination of highly and less immunogenic proteins could be used in serological surveys to detect differences in malaria transmission levels, distinguishing sites of unstable and stable transmission.
Collapse
Affiliation(s)
- Elisabeth Baum
- Department of Medicine, Division of Infectious Diseases, University of California Irvine, Irvine, California, United States of America
- * E-mail:
| | - Kingsley Badu
- Department of Immunology, Noguchi Memorial Institute for Medical Sciences, College of Health Science, University of Ghana, Accra, Ghana
| | - Douglas M. Molina
- Antigen Discovery Inc., Irvine, California, United States of America
| | - Xiaowu Liang
- Antigen Discovery Inc., Irvine, California, United States of America
| | - Philip L. Felgner
- Department of Medicine, Division of Infectious Diseases, University of California Irvine, Irvine, California, United States of America
| | - Guiyun Yan
- Program in Public Health, University of California Irvine, Irvine, California, United States of America
| |
Collapse
|
22
|
Characteristic age distribution of Plasmodium vivax infections after malaria elimination on Aneityum Island, Vanuatu. Infect Immun 2013; 82:243-52. [PMID: 24166950 DOI: 10.1128/iai.00931-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Resurgence is a major concern after malaria elimination. After the initiation of the elimination program on Aneityum Island in 1991, microscopy showed that Plasmodium falciparum disappeared immediately, whereas P. vivax disappeared from 1996 onward, until P. vivax cases were reported in January 2002. By conducting malariometric surveys of the entire population of Aneityum, we investigated the age distribution of individuals with parasites during this epidemic in the context of antimalarial antibody levels and parasite antigen diversity. In July 2002, P. vivax infections were detected by microscopy in 22/759 individuals: 20/298 born after the beginning of the elimination program in 1991, 2/126 born between 1982 and 1991, and none of 335 born before 1982. PCR increased the number of infections detected to 77, distributed among all age groups. Prevalences were 12.1%, 16.7%, and 6.0%, respectively (P < 0.001). In November, a similar age pattern was found, but with fewer infections: 6/746 and 39/741 individuals were found to be infected by microscopy and PCR, respectively. The frequencies of antibody responses to P. vivax were significantly higher in individuals born before 1991 than in younger age groups and were similar to those on Malakula Island, an area of endemicity. Remarkably low antigen diversity (h, 0.15) of P. vivax infections was observed on Aneityum compared with the other islands (h, 0.89 to 1.0). A P. vivax resurgence was observed among children and teenagers on Aneityum, an age distribution similar to those before elimination and on islands where P. vivax is endemic, suggesting that in the absence of significant exposure, immunity may persist, limiting infection levels in adults. The limited parasite gene pool on islands may contribute to this protection.
Collapse
|
23
|
Ondigo BN, Park GS, Gose SO, Ho BM, Ochola LA, Ayodo GO, Ofulla AV, John CC. Standardization and validation of a cytometric bead assay to assess antibodies to multiple Plasmodium falciparum recombinant antigens. Malar J 2012; 11:427. [PMID: 23259607 PMCID: PMC3546950 DOI: 10.1186/1475-2875-11-427] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 12/20/2012] [Indexed: 11/30/2022] Open
Abstract
Background Multiplex cytometric bead assay (CBA) have a number of advantages over ELISA for antibody testing, but little information is available on standardization and validation of antibody CBA to multiple Plasmodium falciparum antigens. The present study was set to determine optimal parameters for multiplex testing of antibodies to P. falciparum antigens, and to compare results of multiplex CBA to ELISA. Methods Antibodies to ten recombinant P. falciparum antigens were measured by CBA and ELISA in samples from 30 individuals from a malaria endemic area of Kenya and compared to known positive and negative control plasma samples. Optimal antigen amounts, monoplex vs multiplex testing, plasma dilution, optimal buffer, number of beads required were assessed for CBA testing, and results from CBA vs. ELISA testing were compared. Results Optimal amounts for CBA antibody testing differed according to antigen. Results for monoplex CBA testing correlated strongly with multiplex testing for all antigens (r = 0.88-0.99, P values from <0.0001 - 0.004), and antibodies to variants of the same antigen were accurately distinguished within a multiplex reaction. Plasma dilutions of 1:100 or 1:200 were optimal for all antigens for CBA testing. Plasma diluted in a buffer containing 0.05% sodium azide, 0.5% polyvinylalcohol, and 0.8% polyvinylpyrrolidone had the lowest background activity. CBA median fluorescence intensity (MFI) values with 1,000 antigen-conjugated beads/well did not differ significantly from MFI with 5,000 beads/well. CBA and ELISA results correlated well for all antigens except apical membrane antigen-1 (AMA-1). CBA testing produced a greater range of values in samples from malaria endemic areas and less background reactivity for blank samples than ELISA. Conclusion With optimization, CBA may be the preferred method of testing for antibodies to P. falciparum antigens, as CBA can test for antibodies to multiple recombinant antigens from a single plasma sample and produces a greater range of values in positive samples and lower background readings for blank samples than ELISA.
Collapse
Affiliation(s)
- Bartholomew N Ondigo
- Department of Biomedical Science and Technology, Maseno University, Maseno, Kenya.
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Rolfes MA, McCarra M, Magak NG, Ernst KC, Dent AE, Lindblade KA, John CC. Development of clinical immunity to malaria in highland areas of low and unstable transmission. Am J Trop Med Hyg 2012; 87:806-12. [PMID: 22987652 DOI: 10.4269/ajtmh.2012.11-0530] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In highland areas of unstable, low malaria transmission, the extent to which immunity to uncomplicated malaria develops with age and intermittent parasite exposure has not been well characterized. We conducted active surveillance for clinical malaria during April 2003-March 2005 in two highland areas of western Kenya (Kapsisiywa and Kipsamoite). In both sites, annual malaria incidence was significantly lower in persons ≥ 15 years of age than in persons < 5 years of age (Kapsisiywa: incidence = 382.9 cases/1,000 persons among persons < 1-4 years of age versus 135.1 cases/1,000 persons among persons ≥ 15 years of age; Kipsamoite: incidence = 233.0 cases/1,000 persons in persons < 1-4 years of age versus 43.3 cases/1,000 persons in persons ≥ 15 years of age). In Kapsisiywa, among persons with malaria, parasite density and axillary body temperature were also significantly lower in persons ≥ 15 years of age than in persons < 5 years of age. Even in highland areas of unstable and low malaria transmission, age is associated with development of clinical immunity to malaria.
Collapse
Affiliation(s)
- Melissa A Rolfes
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
| | | | | | | | | | | | | |
Collapse
|
25
|
Dewasurendra RL, Suriyaphol P, Fernando SD, Carter R, Rockett K, Corran P, Kwiatkowski D, Karunaweera ND. Genetic polymorphisms associated with anti-malarial antibody levels in a low and unstable malaria transmission area in southern Sri Lanka. Malar J 2012; 11:281. [PMID: 22905743 PMCID: PMC3459805 DOI: 10.1186/1475-2875-11-281] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 07/21/2012] [Indexed: 01/08/2023] Open
Abstract
Background The incidence of malaria in Sri Lanka has significantly declined in recent years. Similar trends were seen in Kataragama, a known malaria endemic location within the southern province of the country, over the past five years. This is a descriptive study of anti-malarial antibody levels and selected host genetic mutations in residents of Kataragama, under low malaria transmission conditions. Methods Sera were collected from 1,011 individuals residing in Kataragama and anti-malarial antibodies and total IgE levels were measured by a standardized ELISA technique. Host DNA was extracted and used for genotyping of selected SNPs in known genes associated with malaria. The antibody levels were analysed in relation to the past history of malaria (during past 10 years), age, sex, the location of residence within Kataragama and selected host genetic markers. Results A significant increase in antibodies against Plasmodium falciparum antigens AMA1, MSP2, NANP and Plasmodium vivax antigen MSP1 in individuals with past history of malaria were observed when compared to those who did not. A marked increase of anti-MSP1(Pf) and anti-AMA1(Pv) was also evident in individuals between 45–59 years (when compared to other age groups). Allele frequencies for two SNPs in genes that code for IL-13 and TRIM-5 were found to be significantly different between those who have experienced one or more malaria attacks within past 10 years and those who did not. When antibody levels were classified into a low-high binary trait, significant associations were found with four SNPs for anti-AMA1(Pf); two SNPs for anti-MSP1(Pf); eight SNPs for anti-NANP(Pf); three SNPs for anti-AMA1(Pv); seven SNPs for anti-MSP1(Pv); and nine SNPs for total IgE. Eleven of these SNPs with significant associations with anti-malarial antibody levels were found to be non–synonymous. Conclusions Evidence is suggestive of an age–acquired immunity in this study population in spite of low malaria transmission levels. Several SNPs were in linkage disequilibrium and had a significant association with elevated antibody levels, suggesting that these host genetic mutations might have an individual or collective effect on inducing or/and maintaining high anti–malarial antibody levels.
Collapse
Affiliation(s)
- Rajika L Dewasurendra
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Offeddu V, Thathy V, Marsh K, Matuschewski K. Naturally acquired immune responses against Plasmodium falciparum sporozoites and liver infection. Int J Parasitol 2012; 42:535-48. [DOI: 10.1016/j.ijpara.2012.03.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 03/18/2012] [Accepted: 03/24/2012] [Indexed: 10/28/2022]
|
27
|
Githeko AK, Ototo EN, Guiyun Y. Progress towards understanding the ecology and epidemiology of malaria in the western Kenya highlands: opportunities and challenges for control under climate change risk. Acta Trop 2012; 121:19-25. [PMID: 22015426 DOI: 10.1016/j.actatropica.2011.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/30/2011] [Accepted: 10/06/2011] [Indexed: 11/15/2022]
Abstract
Following severe malaria epidemics in the western Kenya highlands after the late 1980s it became imperative to undertake eco-epidemiological assessments of the disease and determine its drivers, spatial-temporal distribution and control strategies. Extensive research has indicated that the major biophysical drivers of the disease are climate change and variability, terrain, topography, hydrology and immunity. Vector distribution is focalized at valley bottoms and abundance is closely related with drainage efficiency, habitat availability, stability and productivity of the ecosystems. Early epidemic prediction models have been developed and they can be used to assess climate risks that warrant extra interventions with a lead time of 2-4 months. Targeted integrated vector management strategies can significantly reduce the cost on the indoor residual spraying by targeting the foci of transmission in transmission hotspots. Malaria control in the highlands has reduced vector population by 90%, infections by 50-90% in humans and in some cases transmission has been interrupted. Insecticide resistance is increasing and as transmission decreases so will immunity. Active surveillance will be required to monitor and contain emerging threats. More studies on eco-stratification of the disease, based on its major drivers, are required so that interventions are tailored for specific ecosystems. New and innovative control interventions such as house modification with a one-application strategy may reduce the threat from insecticide resistance and low compliance associated with the use of ITNs.
Collapse
Affiliation(s)
- A K Githeko
- Kenya Medical Research Institute, Centre for Global Health Research, Climate and Human Health Research Unit, Kisumu, Kenya.
| | | | | |
Collapse
|
28
|
Tham WH, Healer J, Cowman AF. Erythrocyte and reticulocyte binding-like proteins of Plasmodium falciparum. Trends Parasitol 2011; 28:23-30. [PMID: 22178537 DOI: 10.1016/j.pt.2011.10.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/11/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022]
Abstract
The global agenda for malaria eradication would benefit from development of a highly efficacious vaccine that protects against disease and interrupts transmission of Plasmodium falciparum. It is likely that such a vaccine will be multi-component, with antigens from different stages of the parasite life cycle. In this review, inclusion of blood stage antigens in such a vaccine is discussed. Erythrocyte binding-like (EBL) and P. falciparum reticulocyte binding-like (PfRh) proteins are reviewed with respect to their function in erythrocyte invasion, their role in eliciting antibodies contributing to protective immunity and reduction of invasion, leading subsequently to inhibition of parasite multiplication.
Collapse
Affiliation(s)
- Wai-Hong Tham
- Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC, Australia
| | | | | |
Collapse
|
29
|
Chelimo K, Embury PB, Odada Sumba P, Vulule J, Ofulla AV, Long C, Kazura JW, Moormann AM. Age-related differences in naturally acquired T cell memory to Plasmodium falciparum merozoite surface protein 1. PLoS One 2011; 6:e24852. [PMID: 21935482 PMCID: PMC3174209 DOI: 10.1371/journal.pone.0024852] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 08/19/2011] [Indexed: 12/16/2022] Open
Abstract
Naturally acquired immunity to Plasmodium falciparum malaria in malaria holoendemic areas is characterized by the gradual, age-related development of protection against high-density parasitemia and clinical malaria. Animal studies, and less commonly, observations of humans with malaria, suggest that T-cell responses are important in the development and maintenance of this immunity, which is mediated primarily by antibodies that slow repeated cycles of merozoites through erythrocytes. To advance our rather limited knowledge on human T-cell immunity to blood stage malaria infection, we evaluated CD4 and CD8 T-cell effector memory subset responses to the 42 kDa C-terminal fragment of Merozoite Surface Protein 1 (MSP142), a malaria vaccine candidate, by 49 healthy 0.5 to ≥18 year old residents of a holoendemic area in western Kenya. The proportion of individuals with peripheral blood mononuclear cell MSP142 driven IFN-γ ELISPOT responses increased from 20% (2/20) among 0.5–1 year old children to 90% (9/10) of adults ≥18 years (P = 0.01); parallel increases in the magnitude of IFN-γ responses were observed across all age groups (0.5, 1, 2, 5 and ≥18 years, P = 0.001). Less than 1% of total CD4 and CD8 T-cells from both children and adults produced IFN-γ in response to MSP142. However, adults had higher proportions of MSP142 driven IFN-γ secreting CD4 and CD8 effector memory (CD45RA− CD62L−) T-cells than children (CD4: 50.9% vs. 28.8%, P = 0.036; CD8: 52.1% vs. 18.3%, respectively P = 0.009). In contrast, MSP142 driven IFN-γ secreting naïve-like, transitional (CD45RA+ CD62L+) CD4 and CD8 cells were the predominant T-cell subset among children with significantly fewer of these cells in adults (CD4: 34.9% vs. 5.1%, P = 0.002; CD8: 47.0% vs. 20.5%, respectively, P = 0.030). These data support the concept that meaningful age-related differences exist in the quality of T-cell immunity to malaria antigens such as MSP1.
Collapse
Affiliation(s)
- Kiprotich Chelimo
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- Maseno University, Maseno, Kenya
| | - Paula B. Embury
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Peter Odada Sumba
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - John Vulule
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Carole Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - James W. Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ann M. Moormann
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Pediatrics and Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
30
|
Campo JJ, Whitman TJ, Freilich D, Burgess TH, Martin GJ, Doolan DL. Toward a surrogate marker of malaria exposure: modeling longitudinal antibody measurements under outbreak conditions. PLoS One 2011; 6:e21826. [PMID: 21818270 PMCID: PMC3144875 DOI: 10.1371/journal.pone.0021826] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 06/13/2011] [Indexed: 11/22/2022] Open
Abstract
Background Biomarkers of exposure to Plasmodium falciparum would be a useful tool for the assessment of malaria burden and analysis of intervention and epidemiological studies. Antibodies to pre-erythrocytic antigens represent potential surrogates of exposure. Methods and Findings In an outbreak cohort of U.S. Marines deployed to Liberia, we modeled pre- and post-deployment IgG against P. falciparum sporozoites by immunofluorescence antibody test, and both IgG and IgM against the P. falciparum circumsporozoite protein by enzyme-linked immunosorbant assay. Modeling seroconversion thresholds by a fixed ratio, linear regression or nonlinear regression produced sensitivity for identification of exposed U.S. Marines between 58–70% and specificities between 87–97%, compared with malaria-naïve U.S. volunteers. Exposure was predicted in 30–45% of the cohort. Conclusion Each of the three models tested has merits in different studies, but further development and validation in endemic populations is required. Overall, these models provide support for an antibody-based surrogate marker of exposure to malaria.
Collapse
Affiliation(s)
- Joseph J. Campo
- Naval Medical Research Center, Silver Spring, Maryland, United States of America
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain
- * E-mail: (JJC); (DLD)
| | - Timothy J. Whitman
- Infectious Diseases Department, National Naval Medical Center, Bethesda, Maryland, United States of America
| | - Daniel Freilich
- Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Timothy H. Burgess
- Naval Medical Research Center, Silver Spring, Maryland, United States of America
- Infectious Diseases Department, National Naval Medical Center, Bethesda, Maryland, United States of America
| | - Gregory J. Martin
- Infectious Diseases Department, National Naval Medical Center, Bethesda, Maryland, United States of America
| | - Denise L. Doolan
- Naval Medical Research Center, Silver Spring, Maryland, United States of America
- Division of Immunology, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
- School of Medicine, University of Queensland, Brisbane, Queensland, Australia
- * E-mail: (JJC); (DLD)
| |
Collapse
|
31
|
Ototo EN, Githeko AK, Wanjala CL, Scott TW. Surveillance of vector populations and malaria transmission during the 2009/10 El Niño event in the western Kenya highlands: opportunities for early detection of malaria hyper-transmission. Parasit Vectors 2011; 4:144. [PMID: 21781291 PMCID: PMC3148556 DOI: 10.1186/1756-3305-4-144] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 07/22/2011] [Indexed: 11/10/2022] Open
Abstract
Background Vector control in the highlands of western Kenya has resulted in a significant reduction of malaria transmission and a change in the vectorial system. Climate variability as a result of events such as El Niño increases the highlands suitability for malaria transmission. Surveillance and monitoring is an important component of early transmission risk identification and management. However, below certain disease transmission thresholds, traditional tools for surveillance such as entomological inoculation rates may become insensitive. A rapid diagnostic kit comprising Plasmodium falciparum circumsporozoite surface protein and merozoite surface protein antibodies in humans was tested for early detection of transmission surges in the western Kenya highlands during an El Niño event (October 2009-February 2010). Methods Indoor resting female adult malaria vectors were collected in western Kenya highlands in four selected villages categorized into two valley systems, the U-shaped (Iguhu and Emutete) and the V-shaped valleys (Marani and Fort Ternan) for eight months. Members of the Anopheles gambiae complex were identified by PCR. Blood samples were collected from children 6-15 years old and exposure to malaria was tested using a circum-sporozoite protein and merozoite surface protein immunchromatographic rapid diagnostic test kit. Sporozoite ELISA was conducted to detect circum-sporozoite protein, later used for estimation of entomological inoculation rates. Results Among the four villages studied, an upsurge in antibody levels was first observed in October 2009. Plasmodium falciparum sporozoites were then first observed in December 2009 at Iguhu village and February 2010 at Emutete. Despite the upsurge in Marani and Fort Ternan no sporozoites were detected throughout the eight month study period. The antibody-based assay had much earlier transmission detection ability than the sporozoite-based assay. The proportion of An. arabiensis among An. gambiae s.l. ranged from 2.9-66.7% indicating a rearrangement of the sibling species of the An. gambiae s.l complex. This is possibly an adaptation to insecticide interventions and climate change. Conclusion The changing malaria transmission rates in the western Kenya highlands will lead to more unstable transmission, decreased immunity and a high vulnerability to epidemics unless surveillance tools are improved and effective vector control is sustained.
Collapse
Affiliation(s)
- Ednah N Ototo
- Kenya Medical Research Institute, Centre for Global Health Research, Climate and Human Health Research Unit, P,O, Box 1578, Kisumu, Kenya.
| | | | | | | |
Collapse
|
32
|
Wanjala CL, Waitumbi J, Zhou G, Githeko AK. Identification of malaria transmission and epidemic hotspots in the western Kenya highlands: its application to malaria epidemic prediction. Parasit Vectors 2011; 4:81. [PMID: 21595898 PMCID: PMC3117811 DOI: 10.1186/1756-3305-4-81] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 05/19/2011] [Indexed: 12/02/2022] Open
Abstract
Background Malaria in the western Kenya highlands is characterized by unstable and high transmission variability which results in epidemics during periods of suitable climatic conditions. The sensitivity of a site to malaria epidemics depends on the level of immunity of the human population. This study examined how terrain in the highlands affects exposure and sensitivity of a site to malaria. Methods The study was conducted in five sites in the western Kenya highlands, two U-shaped valleys (Iguhu, Emutete), two V-shaped valleys (Marani, Fort-Ternan) and one plateau (Shikondi) for 16 months among 6-15 years old children. Exposure to malaria was tested using circum-sporozoite protein (CSP) and merozoite surface protein (MSP) immunochromatographic antibody tests; malaria infections were tested by microscopic examination of thick and thin smears, the children's homes were georeferenced using a global positioning system. Paired t-test was used to compare the mean prevalence rates of the sites, K-function was use to determine if the clustering of malaria infections was significant. Results and Discussion The mean antibody prevalence was 22.6% in Iguhu, 24% in Emutete, 11.5% in Shikondi, 8.3% in Fort-Ternan and 9.3% in Marani. The mean malaria infection prevalence was 23.3% in Iguhu, 21.9% in Emutete, 4.7% in Shikondi, 2.9% in Fort-Ternan and 2.4% in Marani. There was a significant difference in the antibodies and malaria infection prevalence between the two valley systems, and between the two valley systems and the plateau (P < 0.05). There was no significant difference in the antibodies and malaria infection prevalence in the two U-shaped valleys (Iguhu and Emutete) and in the V-shaped valleys (Marani and Fort Ternan) (P > 0.05). There was 8.5- fold and a 2-fold greater parasite and antibody prevalence respectively, in the U-shaped compared to the V-shaped valleys. The plateau antibody and parasite prevalence was similar to that of the V-shaped valleys. There was clustering of malaria antibodies and infections around flat areas in the U-shaped valleys, the infections were randomly distributed in the V-shaped valleys and less clustered at the plateau. Conclusion This study showed that the V-shaped ecosystems have very low malaria prevalence and few individuals with an immune response to two major malaria antigens and they can be considered as epidemic hotspots. These populations are at higher risk of severe forms of malaria during hyper-transmission seasons. The plateau ecosystem has a similar infection and immune response to the V-shaped ecosystems. The U-shaped ecosystems are transmission hotspots.
Collapse
Affiliation(s)
- Christine L Wanjala
- Climate and Human Health Research Unit, Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | | | | | | |
Collapse
|
33
|
A peptide-based Plasmodium falciparum circumsporozoite assay to test for serum antibody responses to pre-erythrocyte malaria vaccines. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:776-82. [PMID: 21411600 DOI: 10.1128/cvi.00547-10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Various pre-erythrocyte malaria vaccines are currently in clinical development, and among these is the adenovirus serotype 35-based circumsporozoite (CS) vaccine produced on PER.C6 cells. Although the immunological correlate of protection against malaria remains to be established, the CS antibody titer is a good marker for evaluation of candidate vaccines. Here we describe the validation of an anti-Plasmodium falciparum circumsporozoite antibody enzyme-linked immunosorbent assay (ELISA) based on the binding of antibodies to a peptide antigen mimicking the CS repeat region. The interassay variability was determined to be below a coefficient of variation (CV) of 15%, and sensitivity was sufficient to detect low antibody titers in subjects from endemic regions. Antibody titers were in agreement with total antibody responses to the whole CS protein. Due to its simplicity and high performance, the ELISA is an easy and rapid method for assessment of pre-erythrocyte malaria vaccines based on CS.
Collapse
|
34
|
Casares S, Brumeanu TD, Richie TL. The RTS,S malaria vaccine. Vaccine 2010; 28:4880-94. [PMID: 20553771 DOI: 10.1016/j.vaccine.2010.05.033] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 04/29/2010] [Accepted: 05/12/2010] [Indexed: 12/23/2022]
Abstract
RTS,S is the most advanced candidate vaccine against human malaria. During its remarkable journey from conception and design in the early 1980s to the multicenter Phase 3 trial currently underway across sub-Saharan Africa, RTS,S has overcome tremendous challenges and disproved established vaccine paradigms. In the last several years, Phase 2 studies conducted in infants and children in endemic areas have established the efficacy of RTS,S for reducing morbidity due to clinical malaria. If the results are realized in the Phase 3 trial, the chances for licensure in the near future appear high. Such progress is all the more remarkable given our lack of clear understanding regarding how the vaccine activates the human immune system, the immune correlates of protection or the mechanism whereby a vaccine targeting sporozoites and liver stage parasites can reduce the clinical disease associated with parasitemia. These unanswered questions pose important challenges to be addressed in the quest to understand the protection afforded by RTS,S and to build a more efficacious second generation vaccine against malaria. This review will focus on current knowledge about the protective efficacy of RTS,S and what we have learned regarding its impact on the human immune system.
Collapse
Affiliation(s)
- Sofia Casares
- US Military Malaria Vaccine Program, Naval Medical Research Center/Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | | | | |
Collapse
|
35
|
Cloning and characterization of the acidic ribosomal protein P2 of Cryptosporidium parvum, a new 17-kilodalton antigen. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:954-65. [PMID: 20410328 DOI: 10.1128/cvi.00073-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cryptosporidium infection is commonly observed among children and immunocompromised individuals in developing countries, but large-scale outbreaks of disease among adults have not been reported. In contrast, outbreaks of cryptosporidiosis in the United States and Canada are increasingly common among patients of all ages. Thus, it seems likely that residents of regions where Cryptosporidium is highly endemic acquire some level of immunity, while residents of the developed world do not. A new immunodominant Cryptosporidium parvum antigen in the 15- to 17-kDa size range was identified as the Cryptosporidium parvum 60S acidic ribosomal protein P2 (CpP2). We developed a recombinant protein-based enzyme-linked immunosorbent assay for serologic population surveillance for antibodies that was 89% sensitive and 92% specific relative to the results of the large-format Western blot assay. The human IgG response is directed almost exclusively toward the highly conserved, carboxy-terminal 15 amino acids of the protein. Although IgG antibody cross-reactivity was documented with sera from patients with acute babesiosis, the development of an anti-CpP2 antibody response in our Peru study population correlated better with Cryptosporidium infection than with infection by any other parasitic protozoan. In Haiti, the prevalence of antibodies to CpP2 plateaus at 11 to 20 years of age. Because anti-CpP2 IgG antibodies were found only among residents of countries in the developing world where Cryptosporidium infection occurs early and often, we propose that this response may be a proxy for the intensity of infection and for acquired immunity.
Collapse
|
36
|
Drakeley C, Cook J. Chapter 5. Potential contribution of sero-epidemiological analysis for monitoring malaria control and elimination: historical and current perspectives. ADVANCES IN PARASITOLOGY 2009; 69:299-352. [PMID: 19622411 DOI: 10.1016/s0065-308x(09)69005-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Anti-malarial antibody responses represent an individual's history of exposure to the disease and, as age sero-conversion rates, reflect cumulative malaria exposure in a population. As such these antibody responses are an alternate measure of malaria transmission intensity and have potential in evaluating changes in exposure. This approach was used in the 1970s to evaluate malaria control and eradication attempts in a variety of different ecological settings. These historical studies provided a wealth of information on how serological data might be used to interpret control measures. However they were limited by a lack of standardized antigens and reproducible high-throughput assays. Current techniques using recombinant antigens with a range of immunogenicities, high-throughput enzyme-linked immunosorbent assays (ELISA) and statistical analysis allow a more robust examination of how serological parameters can be used to evaluate factors affecting malaria transmission. Here we present a review of the historical data and use it to assess the serological contribution to monitoring malaria elimination.
Collapse
Affiliation(s)
- Chris Drakeley
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | |
Collapse
|