1
|
Niaré K, Chege T, Rosenkranz M, Mwai K, Saßmannshausen Z, Odera D, Nyamako L, Tuju J, Alfred T, Waitumbi JN, Ogutu B, Sirima SB, Awandare G, Kouriba B, Rayner JC, Osier FHA. Characterization of a novel Plasmodium falciparum merozoite surface antigen and potential vaccine target. Front Immunol 2023; 14:1156806. [PMID: 37122725 PMCID: PMC10140549 DOI: 10.3389/fimmu.2023.1156806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/31/2023] [Indexed: 05/02/2023] Open
Abstract
Introduction Detailed analyses of genetic diversity, antigenic variability, protein localization and immunological responses are vital for the prioritization of novel malaria vaccine candidates. Comprehensive approaches to determine the most appropriate antigen variants needed to provide broad protection are challenging and consequently rarely undertaken. Methods Here, we characterized PF3D7_1136200, which we named Asparagine-Rich Merozoite Antigen (ARMA) based on the analysis of its sequence, localization and immunogenicity. We analyzed IgG and IgM responses against the common variants of ARMA in independent prospective cohort studies in Burkina Faso (N = 228), Kenya (N = 252) and Mali (N = 195) using a custom microarray, Div-KILCHIP. Results We found a marked population structure between parasites from Africa and Asia. African isolates shared 34 common haplotypes, including a dominant pair although the overall selection pressure was directional (Tajima's D = -2.57; Fu and Li's F = -9.69; P < 0.02). ARMA was localized to the merozoite surface, IgG antibodies induced Fc-mediated degranulation of natural killer cells and strongly inhibited parasite growth in vitro. We found profound serological diversity, but IgG and IgM responses were highly correlated and a hierarchical clustering analysis identified only three major serogroups. Protective IgG and IgM antibodies appeared to target both cross-reactive and distinct epitopes across variants. However, combinations of IgG and IgM antibodies against selected variants were associated with complete protection against clinical episodes of malaria. Discussion Our systematic strategy exploits genomic data to deduce the handful of antigen variants with the strongest potential to induce broad protection and may be broadly applicable to other complex pathogens for which effective vaccines remain elusive.
Collapse
Affiliation(s)
- Karamoko Niaré
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Centre for Geographic Medicine Research—Coast, Kilifi, Kenya
- Malaria Research and Training Centre (MRTC), Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
- *Correspondence: Karamoko Niaré, ; Faith H. A. Osier,
| | - Timothy Chege
- Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Centre for Geographic Medicine Research—Coast, Kilifi, Kenya
| | - Micha Rosenkranz
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Kennedy Mwai
- Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Centre for Geographic Medicine Research—Coast, Kilifi, Kenya
- Epidemiology and Biostatistics Division, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Zoe Saßmannshausen
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Dennis Odera
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Lydia Nyamako
- Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Centre for Geographic Medicine Research—Coast, Kilifi, Kenya
| | - James Tuju
- Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Centre for Geographic Medicine Research—Coast, Kilifi, Kenya
| | - Tiono Alfred
- Public Health Department, Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso
| | - John N. Waitumbi
- Basic Science Laboratory, US Army Medical Research Directorate-Africa/Kenya Medical Research Institute, Kisumu, Kenya
| | - Bernhards Ogutu
- Kenya Medical Research Institute, Centre for Clinical Research, Nairobi, Kenya
| | | | - Gordon Awandare
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Bourema Kouriba
- Malaria Research and Training Centre (MRTC), Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- Centre d’Infectiologie Charles Mérieux-Mali, Bamako, Mali
| | - Julian C. Rayner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Faith H. A. Osier
- Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Centre for Geographic Medicine Research—Coast, Kilifi, Kenya
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
- *Correspondence: Karamoko Niaré, ; Faith H. A. Osier,
| |
Collapse
|
2
|
Coulibaly D, Kone AK, Kane B, Guindo B, Tangara B, Sissoko M, Maiga F, Traore K, Diawara A, Traore A, Thera A, Sissoko MS, Doumbo OK, Travassos MA, Thera MA. Shifts in the clinical epidemiology of severe malaria after scaling up control strategies in Mali. Front Neurol 2022; 13:988960. [PMID: 36523346 PMCID: PMC9744791 DOI: 10.3389/fneur.2022.988960] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/17/2022] [Indexed: 11/30/2022] Open
Abstract
A decrease in malaria incidence following implementation of control strategies such as use of artemisinin-based combination therapies, insecticide-impregnated nets, intermittent preventive treatment during pregnancy and seasonal malaria chemoprevention (SMC) has been observed in many parts of Africa. We hypothesized that changes in malaria incidence is accompanied by a change in the predominant clinical phenotypes of severe malaria. To test our hypothesis, we used data from a severe malaria case-control study that lasted from 2014–2019 to describe clinical phenotypes of severe forms experienced by participants enrolled in Bandiagara, Bamako, and Sikasso, in Mali. We also analyzed data from hospital records of inpatient children at a national referral hospital in Bamako. Among 97 cases of severe malaria in the case-control study, there was a predominance of severe malarial anemia (49.1%). The frequency of cerebral malaria was 35.4, and 16.5% of cases had a mixed clinical phenotype (concurrent cerebral malaria and severe anemia). National referral hospital record data in 2013–15 showed 24.3% of cases had severe malarial anemia compared to 51.7% with cerebral malaria. In the years after SMC scale-up, severe malarial anemia cases increased to 30.1%, (P = 0.019), whereas cerebral malaria cases decreased to 45.5% (P = 0.025). In addition, the predominant age group for each severe malaria phenotype was the 0–1-year-olds. The decrease in malaria incidence noted with the implementation of control strategies may be associated with a change in the clinical expression patterns of severe malaria, including a potential shift in severe malaria burden to age groups not receiving seasonal malaria chemoprevention.
Collapse
|
3
|
Sobota RS, Goron AR, Berry AA, Bailey JA, Coulibaly D, Adams M, Kone AK, Kouriba B, Doumbo OK, Sztein MB, Felgner PL, Plowe CV, Lyke KE, Thera MA, Travassos MA. Serologic and Cytokine Profiles of Children with Concurrent Cerebral Malaria and Severe Malarial Anemia Are Distinct from Other Subtypes of Severe Malaria. Am J Trop Med Hyg 2022; 107:315-319. [PMID: 35895583 PMCID: PMC9393435 DOI: 10.4269/ajtmh.22-0135] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/25/2022] [Indexed: 11/07/2022] Open
Abstract
We used a protein microarray featuring Plasmodium falciparum field variants of a merozoite surface antigen to examine malaria exposure in Malian children with different severe malaria syndromes. Unlike children with cerebral malaria alone or severe malarial anemia alone, those with concurrent cerebral malaria and severe malarial anemia had serologic responses demonstrating a broader prior parasite exposure pattern than matched controls with uncomplicated disease. Comparison of levels of malaria-related cytokines revealed that children with the concurrent phenotype had elevated levels of interleukin (IL)-6, IL-8, and IL-10. Our results suggest that the pathophysiology of this severe subtype is unique and merits further investigation.
Collapse
Affiliation(s)
- Rafal S. Sobota
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
- Ken and Ruth Davee Department of Neurology, Northwestern University, Chicago, Illinois
| | - Abby R. Goron
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Andrea A. Berry
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jason A. Bailey
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Matthew Adams
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Abdoulaye K. Kone
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Bourema Kouriba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Ogobara K. Doumbo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Marcelo B. Sztein
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Philip L. Felgner
- Division of Infectious Diseases, Department of Medicine, University of California, Irvine, California
| | - Christopher V. Plowe
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Kirsten E. Lyke
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Mahamadou A. Thera
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mark A. Travassos
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| |
Collapse
|
4
|
Ventimiglia NT, Stucke EM, Coulibaly D, Berry AA, Lyke KE, Laurens MB, Bailey JA, Adams M, Niangaly A, Kone AK, Takala-Harrison S, Kouriba B, Doumbo OK, Felgner PL, Plowe CV, Thera MA, Travassos MA. Malian adults maintain serologic responses to virulent PfEMP1s amid seasonal patterns of fluctuation. Sci Rep 2021; 11:14401. [PMID: 34257318 PMCID: PMC8277812 DOI: 10.1038/s41598-021-92974-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 06/08/2021] [Indexed: 12/03/2022] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein-1s (PfEMP1s), diverse malaria proteins expressed on the infected erythrocyte surface, play an important role in pathogenesis, mediating adhesion to host vascular endothelium. Antibodies to particular non-CD36-binding PfEMP1s are associated with protection against severe disease. We hypothesized that given lifelong P. falciparum exposure, Malian adults would have broad PfEMP1 serorecognition and high seroreactivity levels during follow-up, particularly to non-CD36-binding PfEMP1s such as those that attach to endothelial protein C receptor (EPCR) and intercellular adhesion molecule-1 (ICAM-1). Using a protein microarray, we determined serologic responses to 166 reference PfEMP1 fragments during a dry and subsequent malaria transmission season in Malian adults. Malian adult sera had PfEMP1 serologic responses throughout the year, with decreased reactivity to a small subset of PfEMP1 fragments during the dry season and increases in reactivity to a different subset of PfEMP1 fragments during the subsequent peak malaria transmission season, especially for intracellular PfEMP1 domains. For some individuals, PfEMP1 serologic responses increased after the dry season, suggesting antigenic switching during asymptomatic infection. Adults were more likely to experience variable serorecognition of CD36-binding PfEMP1s than non-CD36-binding PfEMP1s that bind EPCR or ICAM-1, which remained serorecognized throughout the year. Sustained seroreactivity to non-CD36-binding PfEMP1s throughout adulthood amid seasonal fluctuation patterns may reflect underlying protective severe malaria immunity and merits further investigation.
Collapse
Affiliation(s)
| | - Emily M Stucke
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Drissa Coulibaly
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Andrea A Berry
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kirsten E Lyke
- University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Jason A Bailey
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Matthew Adams
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Amadou Niangaly
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Abdoulaye K Kone
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | | | - Bourema Kouriba
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Ogobara K Doumbo
- University of Sciences, Techniques and Technologies, Bamako, Mali
| | | | | | | | | |
Collapse
|
5
|
Parra M, Yang J, Weitner M, Akkoyunlu M. Neonatal mice resist Plasmodium yoelii infection until exposed to para-aminobenzoic acid containing diet after weaning. Sci Rep 2021; 11:90. [PMID: 33420157 PMCID: PMC7794322 DOI: 10.1038/s41598-020-79703-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/04/2020] [Indexed: 12/03/2022] Open
Abstract
We developed a newborn (NB) mouse Plasmodium yoelii NL infection model to study malaria in early age. Surprisingly, the onset of parasitemia in P. yoelii challenged NB mice was delayed compared to adults and coincided with the weaning date when weanlings switched from maternal milk to normal chow diet. Also, compared to adult mice, parasitemia resolved much later (48 days vs 20 days post challenge) and the peak parasitemia was twice as high in weanlings. Concurrently, weanlings’ germinal center reaction was delayed and diminished compared to adult mice. Maternal milk is deficient in para-aminobenzoic acid (PABA), which is required for de novo folate synthesis by Plasmodium. Suggesting a possible role for the protection afforded by PABA-deficient maternal milk, mice fed with a PABA-deficient diet after the weaning continued to control parasitemia. Despite the reduced parasitemia, these mice developed robust T follicular helper (Tfh) responses and were protected from a second P. yoelii challenge. The NB malaria model provides mechanistic insight into the human infant malaria manifestations where a diet solely based on breast-feeding reduces the incidence of severe malaria in infants. NB mice experiments also support further studies to investigate dietary PABA restriction in the management of severe malaria in infants.
Collapse
Affiliation(s)
- Marcela Parra
- Center for Biologics Evaluation and Research, Division of Bacterial Allergenic and Parasitic Diseases, US Food and Drug Administration, Silver Spring, MD, USA
| | - Jiyeon Yang
- Center for Biologics Evaluation and Research, Division of Bacterial Allergenic and Parasitic Diseases, US Food and Drug Administration, Silver Spring, MD, USA
| | - Megan Weitner
- Center for Biologics Evaluation and Research, Division of Bacterial Allergenic and Parasitic Diseases, US Food and Drug Administration, Silver Spring, MD, USA.,Viral & Rickettsial Diseases Department (NMRC VRDD), Naval Medical Research Center, Silver Spring, MD, USA
| | - Mustafa Akkoyunlu
- Center for Biologics Evaluation and Research, Division of Bacterial Allergenic and Parasitic Diseases, US Food and Drug Administration, Silver Spring, MD, USA. .,DBPAP, US FDA, CBER, 10903 New Hampshire Ave., Building 52/72, Room, 5214, Silver Spring, MD, 209903, USA.
| |
Collapse
|
6
|
Antibodies to Peptides in Semiconserved Domains of RIFINs and STEVORs Correlate with Malaria Exposure. mSphere 2019; 4:4/2/e00097-19. [PMID: 30894432 PMCID: PMC6429043 DOI: 10.1128/msphere.00097-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malaria, an infectious disease caused by the parasite Plasmodium falciparum, causes nearly 435,000 deaths annually worldwide. RIFINs and STEVORs are two variant surface antigen families that are involved in malaria pathogenesis and immune evasion. Recent work has shown that a lack of humoral immunity to these proteins is associated with severe malaria vulnerability in Malian children. This is the first study to have compared serologic responses of children and adults to RIFINs and STEVORs in settings of malaria endemicity and to examine such serologic responses before and after a clinical malaria episode. Using microarrays, we determined that the semiconserved domains in these two parasite variant surface antigen families harbor peptides whose seroreactivity reflects malaria exposure. A similar approach has the potential to illuminate the role of variant surface antigens in the development of natural immunity to clinical malaria. Potential vaccines for severe malaria should include consideration of peptides within the semiconserved domains of RIFINs and STEVORs. The repetitive interspersed family (RIFIN) and the subtelomeric variable open reading frame (STEVOR) family represent two of three major Plasmodium falciparum variant surface antigen families involved in malaria pathogenesis and immune evasion and are potential targets in the development of natural immunity. Protein and peptide microarrays populated with RIFINs and STEVORs associated with severe malaria vulnerability in Malian children were probed with adult and pediatric sera to identify epitopes that reflect malaria exposure. Adult sera recognized and reacted with greater intensity to all STEVOR proteins than pediatric sera did. Serorecognition of and seroreactivity to peptides within the semiconserved domain of STEVORs increased with age and seasonal malaria exposure, while serorecognition and seroreactivity increased for the semiconserved and second hypervariable domains of RIFINs only with age. Serologic responses to RIFIN and STEVOR peptides within the semiconserved domains may play a role in natural immunity to severe malaria. IMPORTANCE Malaria, an infectious disease caused by the parasite Plasmodium falciparum, causes nearly 435,000 deaths annually worldwide. RIFINs and STEVORs are two variant surface antigen families that are involved in malaria pathogenesis and immune evasion. Recent work has shown that a lack of humoral immunity to these proteins is associated with severe malaria vulnerability in Malian children. This is the first study to have compared serologic responses of children and adults to RIFINs and STEVORs in settings of malaria endemicity and to examine such serologic responses before and after a clinical malaria episode. Using microarrays, we determined that the semiconserved domains in these two parasite variant surface antigen families harbor peptides whose seroreactivity reflects malaria exposure. A similar approach has the potential to illuminate the role of variant surface antigens in the development of natural immunity to clinical malaria. Potential vaccines for severe malaria should include consideration of peptides within the semiconserved domains of RIFINs and STEVORs.
Collapse
|
7
|
Children with cerebral malaria or severe malarial anaemia lack immunity to distinct variant surface antigen subsets. Sci Rep 2018; 8:6281. [PMID: 29674705 PMCID: PMC5908851 DOI: 10.1038/s41598-018-24462-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/28/2018] [Indexed: 01/08/2023] Open
Abstract
Variant surface antigens (VSAs) play a critical role in severe malaria pathogenesis. Defining gaps, or “lacunae”, in immunity to these Plasmodium falciparum antigens in children with severe malaria would improve our understanding of vulnerability to severe malaria and how protective immunity develops. Using a protein microarray with 179 antigen variants from three VSA families as well as more than 300 variants of three other blood stage P. falciparum antigens, reactivity was measured in sera from Malian children with cerebral malaria or severe malarial anaemia and age-matched controls. Sera from children with severe malaria recognized fewer extracellular PfEMP1 fragments and were less reactive to specific fragments compared to controls. Following recovery from severe malaria, convalescent sera had increased reactivity to certain non-CD36 binding PfEMP1s, but not other malaria antigens. Sera from children with severe malarial anaemia reacted to fewer VSAs than did sera from children with cerebral malaria, and both of these groups had lacunae in their seroreactivity profiles in common with children who had both cerebral malaria and severe malarial anaemia. This microarray-based approach may identify a subset of VSAs that could inform the development of a vaccine to prevent severe disease or a diagnostic test to predict at-risk children.
Collapse
|
8
|
Coulibaly D, Travassos MA, Tolo Y, Laurens MB, Kone AK, Traore K, Sissoko M, Niangaly A, Diarra I, Daou M, Guindo B, Rebaudet S, Kouriba B, Dessay N, Piarroux R, Plowe CV, Doumbo OK, Thera MA, Gaudart J. Spatio-Temporal Dynamics of Asymptomatic Malaria: Bridging the Gap Between Annual Malaria Resurgences in a Sahelian Environment. Am J Trop Med Hyg 2017; 97:1761-1769. [PMID: 29141722 PMCID: PMC5805033 DOI: 10.4269/ajtmh.17-0074] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
In areas of seasonal malaria transmission, the incidence rate of malaria infection is presumed to be near zero at the end of the dry season. Asymptomatic individuals may constitute a major parasite reservoir during this time. We conducted a longitudinal analysis of the spatio-temporal distribution of clinical malaria and asymptomatic parasitemia over time in a Malian town to highlight these malaria transmission dynamics. For a cohort of 300 rural children followed over 2009–2014, periodicity and phase shift between malaria and rainfall were determined by spectral analysis. Spatial risk clusters of clinical episodes or carriage were identified. A nested-case-control study was conducted to assess the parasite carriage factors. Malaria infection persisted over the entire year with seasonal peaks. High transmission periods began 2–3 months after the rains began. A cluster with a low risk of clinical malaria in the town center persisted in high and low transmission periods. Throughout 2009–2014, cluster locations did not vary from year to year. Asymptomatic and gametocyte carriage were persistent, even during low transmission periods. For high transmission periods, the ratio of asymptomatic to clinical cases was approximately 0.5, but was five times higher during low transmission periods. Clinical episodes at previous high transmission periods were a protective factor for asymptomatic carriage, but carrying parasites without symptoms at a previous high transmission period was a risk factor for asymptomatic carriage. Stable malaria transmission was associated with sustained asymptomatic carriage during dry seasons. Control strategies should target persistent low-level parasitemia clusters to interrupt transmission.
Collapse
Affiliation(s)
- Drissa Coulibaly
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mark A Travassos
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Youssouf Tolo
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Matthew B Laurens
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Abdoulaye K Kone
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Karim Traore
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mody Sissoko
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Amadou Niangaly
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Issa Diarra
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Modibo Daou
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Boureima Guindo
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | | | - Bourema Kouriba
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Nadine Dessay
- UMR ESPACE-DEV, IRD, Maison de la Télédétection, Montpellier, France
| | | | - Christopher V Plowe
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ogobara K Doumbo
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mahamadou A Thera
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Jean Gaudart
- Aix Marseille University, IRD, INSERM, SESSTIM, Marseille, France
| |
Collapse
|
9
|
Thera MA, Coulibaly D, Kone AK, Guindo AB, Traore K, Sall AH, Diarra I, Daou M, Traore IM, Tolo Y, Sissoko M, Niangaly A, Arama C, Baby M, Kouriba B, Sissoko MS, Sagara I, Toure OB, Dolo A, Diallo DA, Remarque E, Chilengi R, Noor R, Sesay S, Thomas A, Kocken CH, Faber BW, Imoukhuede EB, Leroy O, Doumbo OK. Phase 1 randomized controlled trial to evaluate the safety and immunogenicity of recombinant Pichia pastoris-expressed Plasmodium falciparum apical membrane antigen 1 (PfAMA1-FVO [25-545]) in healthy Malian adults in Bandiagara. Malar J 2016; 15:442. [PMID: 27577237 PMCID: PMC5006270 DOI: 10.1186/s12936-016-1466-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The safety and immunogenicity of PfAMA1, adjuvanted with Alhydrogel(®) was assessed in malaria-experienced Malian adults. The malaria vaccine, PfAMA1-FVO [25-545] is a recombinant protein Pichia pastoris-expressed AMA-1 from Plasmodium falciparum FVO clone adsorbed to Alhydrogel(®), the control vaccine was tetanus toxoid produced from formaldehyde detoxified and purified tetanus toxin. METHODS A double blind randomized controlled phase 1 study enrolled and followed 40 healthy adults aged 18-55 years in Bandiagara, Mali, West Africa, a rural setting with intense seasonal transmission of P. falciparum malaria. Volunteers were randomized to receive either 50 µg of malaria vaccine or the control vaccine. Three doses of vaccine were given on Days 0, 28 and 56, and participants were followed for 1 year. Solicited symptoms were assessed for seven days and unsolicited symptoms for 28 days after each vaccination. Serious adverse events were assessed throughout the study. The titres of anti-AMA-1 antibodies were measured by ELISA and P. falciparum growth inhibition assays were performed. RESULTS Commonest local solicited adverse events were the injection site pain and swelling more frequent in the PfAMA1 group. No vaccine related serious adverse events were reported. A significant 3.5-fold increase of anti-AMA-1 IgG antibodies was observed in malaria vaccine recipients four weeks after the third immunization compared to the control group. CONCLUSION The PfAMA1 showed a good safety profile. Most adverse events reported were of mild to moderate intensity. In addition, the vaccine induced a significant though short-lived increase in the anti-AMA1 IgG titres. Registered on www.clinicaltrials.gov with the number NCT00431808.
Collapse
Affiliation(s)
- Mahamadou A Thera
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali.
| | - Drissa Coulibaly
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Abdoulaye K Kone
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Ando B Guindo
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Karim Traore
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Abdourhamane H Sall
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Issa Diarra
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Modibo Daou
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Idrissa M Traore
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Youssouf Tolo
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mady Sissoko
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Amadou Niangaly
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Charles Arama
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mounirou Baby
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Bourema Kouriba
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Mahamadou S Sissoko
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Issaka Sagara
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Ousmane B Toure
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Amagana Dolo
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Dapa A Diallo
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - Edmond Remarque
- Biomedical Primate Research Center (BPRC), P.O. Box 3306, 2280 GH, Rijswijk, The Netherlands
| | - Roma Chilengi
- Center for Infectious Diseases Research in Zambia (CIDRZ), P.O. Box 34681, Lusaka, 10101, Zambia
| | - Ramadhani Noor
- African Malaria Network Trust (AMANET), P.O. Box 33207, Dar Es Salaam, Tanzania
| | - Sanie Sesay
- Medical Research Council, P.O. Box 273, Banjul, The Gambia
| | - Alan Thomas
- Biomedical Primate Research Center (BPRC), P.O. Box 3306, 2280 GH, Rijswijk, The Netherlands
| | - Clemens H Kocken
- Biomedical Primate Research Center (BPRC), P.O. Box 3306, 2280 GH, Rijswijk, The Netherlands
| | - Bart W Faber
- Biomedical Primate Research Center (BPRC), P.O. Box 3306, 2280 GH, Rijswijk, The Netherlands
| | | | - Odile Leroy
- European Vaccine Initiative, European Vaccine Initiative, Im Neuenheimer Feld 307, 69120, Heidelberg, Germany
| | - Ogobara K Doumbo
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali
| |
Collapse
|
10
|
Graves SF, Kouriba B, Diarra I, Daou M, Niangaly A, Coulibaly D, Keita Y, Laurens MB, Berry AA, Vekemans J, Ripley Ballou W, Lanar DE, Dutta S, Gray Heppner D, Soisson L, Diggs CL, Thera MA, Doumbo OK, Plowe CV, Sztein MB, Lyke KE. Strain-specific Plasmodium falciparum multifunctional CD4+ T cell cytokine expression in Malian children immunized with the FMP2.1/AS02A vaccine candidate. Vaccine 2016; 34:2546-55. [DOI: 10.1016/j.vaccine.2016.04.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 03/24/2016] [Accepted: 04/07/2016] [Indexed: 12/17/2022]
|
11
|
Travassos MA, Coulibaly D, Laurens MB, Dembélé A, Tolo Y, Koné AK, Traoré K, Niangaly A, Guindo A, Wu Y, Berry AA, Jacob CG, Takala-Harrison S, Adams M, Shrestha B, Mu AZ, Kouriba B, Lyke KE, Diallo DA, Doumbo OK, Plowe CV, Thera MA. Hemoglobin C Trait Provides Protection From Clinical Falciparum Malaria in Malian Children. J Infect Dis 2015; 212:1778-86. [PMID: 26019283 PMCID: PMC4633765 DOI: 10.1093/infdis/jiv308] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 05/14/2015] [Indexed: 11/12/2022] Open
Abstract
Background. Hemoglobin C trait, like hemoglobin S trait, protects against severe malaria in children, but it is unclear whether hemoglobin C trait also protects against uncomplicated malaria. We hypothesized that Malian children with hemoglobin C trait would have a lower risk of clinical malaria than children with hemoglobin AA. Methods. Three hundred children aged 0–6 years were enrolled in a cohort study of malaria incidence in Bandiagara, Mali, with continuous passive and monthly active follow-up from June 2009 to June 2010. Results. Compared to hemoglobin AA children (n = 242), hemoglobin AC children (n = 39) had a longer time to first clinical malaria episode (hazard ratio [HR], 0.19; P = .001; 364 median malaria-free days vs 181 days), fewer episodes of clinical malaria, and a lower cumulative parasite burden. Similarly, hemoglobin AS children (n = 14) had a longer time to first clinical malaria episode than hemoglobin AA children (HR, 0.15; P = .015; 364 median malaria-free days vs 181 days), but experienced the most asymptomatic malaria infections of any group. Conclusions. Both hemoglobin C and S traits exerted a protective effect against clinical malaria episodes, but appeared to do so by mechanisms that differentially affect the response to infecting malaria parasites.
Collapse
Affiliation(s)
- Mark A Travassos
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Matthew B Laurens
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Ahmadou Dembélé
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Youssouf Tolo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Abdoulaye K Koné
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Karim Traoré
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Amadou Niangaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Aldiouma Guindo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako Centre de Recherche et de Lutte contre la Drépanocytose, Bamako, Mali
| | - Yukun Wu
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine
| | - Andrea A Berry
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Christopher G Jacob
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Shannon Takala-Harrison
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Matthew Adams
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Biraj Shrestha
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Amy Z Mu
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Bourema Kouriba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Kirsten E Lyke
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine
| | - Dapa A Diallo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako Centre de Recherche et de Lutte contre la Drépanocytose, Bamako, Mali
| | - Ogobara K Doumbo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| | - Christopher V Plowe
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine Howard Hughes Medical Institute, Baltimore, Maryland
| | - Mahamadou A Thera
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako
| |
Collapse
|
12
|
Das LK, Padhi B, Sahu SS. Prediction of outcome of severe falciparum malaria in Koraput, Odisha, India: A hospital-based study. Trop Parasitol 2014; 4:105-10. [PMID: 25250231 PMCID: PMC4166794 DOI: 10.4103/2229-5070.138538] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 08/12/2014] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Infection with Plasmodium falciparum, caused 627,000 deaths in 2012 in the world. P. falciparum infection causes myriads of clinical manifestations. Exact clinical manifestation resulting in poor prognosis in hyper-endemic epidemiological settings need to be ascertained to save human lives. A hospital-based study was conducted to elucidate the different severe clinical presentations of falciparum malaria and to examine the critical clinical and laboratory parameters on the prognosis of these severe manifestations in a stable hyper-endemic falciparum area in the state of Odisha, India. MATERIALS AND METHODS Consecutive patients admitted in a tertiary care hospital with severe manifestations of malaria as per WHO criteria and confirmed by parasitological examination were included in the study. A detailed clinical and biochemical parameters were examined. Clinical data were reviewed before being double entered into a computer and analyzed. Statistical analyses were carried out using Epi Info 6.04. Continuous and normal distributed data were compared by two-tailed Student's t-test and proportions compared with χ(2) tests with Yates' correction or Fisher's exact test. RESULTS AND DISCUSSION A total of 1320 patients with clinical malaria, diagnosed at outpatients' department were admitted in the hospital during the 1 year study period of which, 292 (22.1%) were children under 14 years of age. The major clinical categories on admission were hyperpyrexia (70.7%), cerebral malaria (9.4%), malarial anemia (7.7%), algid malaria (1.5%), and malaria associated categories were respiratory infection (2.2%), hepatitis (2.0%), urinary tract infection (1.8%), enteric fever (3.3%), and sickle cell disease (1.2%). The overall case fatality rate (CFR) was 4.3 (57/1320). The CFR in children 12.3 (36/292) was significantly higher when compared to adults, that is, 2.0 (21/1028). The major causes of death were cerebral malaria (45.6%), malaria along with a respiratory infection (19.3%) and anemia (10.5%). Malarial anemia along sickle cell disease accounted for 19.3% of all malaria related deaths. Proportion of mortality due to acute renal failure was higher in adults. Biochemical parameters suggest involvement of multiple organs. The findings suggest that the area can be effectively managed by sustained and continuous preventive and curative efforts.
Collapse
Affiliation(s)
- Lalit Kumar Das
- Unit of Clinical Epidemiology and Chemotherapy, Vector Control Research Centre (Indian Council of Medical Research), Medical Complex, Indira Nagar, Puducherry, India
| | - Bishwanath Padhi
- Department of Internal Medicine, District Headquarters Hospital, Koraput, Odisha, India
| | - Sudhansu Sekar Sahu
- Unit of Clinical Epidemiology and Chemotherapy, Vector Control Research Centre (Indian Council of Medical Research), Medical Complex, Indira Nagar, Puducherry, India
| |
Collapse
|
13
|
Coulibaly D, Travassos MA, Kone AK, Tolo Y, Laurens MB, Traore K, Diarra I, Niangaly A, Daou M, Dembele A, Sissoko M, Guindo B, Douyon R, Guindo A, Kouriba B, Sissoko MS, Sagara I, Plowe CV, Doumbo OK, Thera MA. Stable malaria incidence despite scaling up control strategies in a malaria vaccine-testing site in Mali. Malar J 2014; 13:374. [PMID: 25238721 PMCID: PMC4180968 DOI: 10.1186/1475-2875-13-374] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/11/2014] [Indexed: 11/10/2022] Open
Abstract
Background The recent decline in malaria incidence in many African countries has been attributed to the provision of prompt and effective anti-malarial treatment using artemisinin-based combination therapy (ACT) and to the widespread distribution of long-lasting, insecticide-treated bed nets (LLINs). At a malaria vaccine-testing site in Bandiagara, Mali, ACT was introduced in 2004, and LLINs have been distributed free of charge since 2007 to infants after they complete the Expanded Programme of Immunization (EPI) schedule and to pregnant women receiving antenatal care. These strategies may have an impact on malaria incidence. Methods To document malaria incidence, a cohort of 400 children aged 0 to 14 years was followed for three to four years up to July 2013. Monthly cross-sectional surveys were done to measure the prevalence of malaria infection and anaemia. Clinical disease was measured both actively and passively through continuous availability of primary medical care. Measured outcomes included asymptomatic Plasmodium infection, anaemia and clinical malaria episodes. Results The incidence rate of clinical malaria varied significantly from June 2009 to July 2013 without a clear downward trend. A sharp seasonality in malaria illness incidence was observed with higher clinical malaria incidence rates during the rainy season. Parasite and anaemia point prevalence also showed seasonal variation with much higher prevalence rates during rainy seasons compared to dry seasons. Conclusions Despite the scaling up of malaria prevention and treatment, including the widespread use of bed nets, better diagnosis and wider availability of ACT, malaria incidence did not decrease in Bandiagara during the study period.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Mahamadou A Thera
- Malaria Research & Training Centre, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies, Bamako, Mali.
| |
Collapse
|
14
|
Extended safety, immunogenicity and efficacy of a blood-stage malaria vaccine in malian children: 24-month follow-up of a randomized, double-blinded phase 2 trial. PLoS One 2013; 8:e79323. [PMID: 24260195 PMCID: PMC3832522 DOI: 10.1371/journal.pone.0079323] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 09/17/2013] [Indexed: 11/29/2022] Open
Abstract
Background The FMP2.1/AS02A candidate malaria vaccine was tested in a Phase 2 study in Mali. Based on results from the first eight months of follow-up, the vaccine appeared well-tolerated and immunogenic. It had no significant efficacy based on the primary endpoint, clinical malaria, but marginal efficacy against clinical malaria in secondary analyses, and high allele-specific efficacy. Extended follow-up was conducted to evaluate extended safety, immunogenicity and efficacy. Methods A randomized, double-blinded trial of safety, immunogenicity and efficacy of the candidate Plasmodium falciparum apical membrane antigen 1 (AMA1) vaccine FMP2.1/AS02A was conducted in Bandiagara, Mali. Children aged 1–6 years were randomized in a 1∶1 ratio to receive FMP2.1/AS02A or control rabies vaccine on days 0, 30 and 60. Using active and passive surveillance, clinical malaria and adverse events as well as antibodies against P. falciparum AMA1 were monitored for 24 months after the first vaccination, spanning two malaria seasons. Findings 400 children were enrolled. Serious adverse events occurred in nine participants in the FMP2.1/AS02A group and three in the control group; none was considered related to study vaccination. After two years, anti-AMA1 immune responses remained significantly higher in the FMP2.1/AS02A group than in the control group. For the entire 24-month follow-up period, vaccine efficacy was 7.6% (p = 0.51) against first clinical malaria episodes and 9.9% (p = 0.19) against all malaria episodes. For the final 16-month follow-up period, vaccine efficacy was 0.9% (p = 0.98) against all malaria episodes. Allele-specific efficacy seen in the first malaria season did not extend into the second season of follow-up. Interpretation Allele-specific vaccine efficacy was not sustained in the second malaria season, despite continued high levels of anti-AMA1 antibodies. This study presents an opportunity to evaluate correlates of partial protection against clinical malaria that waned during the second malaria season. Trial Registration Clinicaltrials.gov NCT00460525 NCT00460525
Collapse
|
15
|
Coulibaly D, Rebaudet S, Travassos M, Tolo Y, Laurens M, Kone AK, Traore K, Guindo A, Diarra I, Niangaly A, Daou M, Dembele A, Sissoko M, Kouriba B, Dessay N, Gaudart J, Piarroux R, Thera MA, Plowe CV, Doumbo OK. Spatio-temporal analysis of malaria within a transmission season in Bandiagara, Mali. Malar J 2013; 12:82. [PMID: 23452561 PMCID: PMC3618208 DOI: 10.1186/1475-2875-12-82] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 02/26/2013] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Heterogeneous patterns of malaria transmission are thought to be driven by factors including host genetics, distance to mosquito breeding sites, housing construction, and socio-behavioural characteristics. Evaluation of local transmission epidemiology to characterize malaria risk is essential for planning malaria control and elimination programmes. The use of geographical information systems (GIS) techniques has been a major asset to this approach. To assess time and space distribution of malaria disease in Bandiagara, Mali, within a transmission season, data were used from an ongoing malaria incidence study that enrolled 300 participants aged under six years old". METHODS Children's households were georeferenced using a handheld global position system. Clinical malaria was defined as a positive blood slide for Plasmodium falciparum asexual stages associated with at least one of the following signs: headache, body aches, fever, chills and weakness. Daily rainfall was measured at the local weather station.Landscape features of Bandiagara were obtained from satellite images and field survey. QGIS™ software was used to map malaria cases, affected and non-affected children, and the number of malaria episodes per child in each block of Bandiagara. Clusters of high or low risk were identified under SaTScan(®) software according to a Bernoulli model. RESULTS From June 2009 to May 2010, 296 clinical malaria cases were recorded. Though clearly temporally related to the rains, Plasmodium falciparum occurrence persisted late in the dry season. Two "hot spots" of malaria transmission also found, notably along the Yamé River, characterized by higher than expected numbers of malaria cases, and high numbers of clinical episodes per child. Conversely, the north-eastern sector of the town had fewer cases despite its proximity to a large body of standing water which was mosquito habitat. CONCLUSION These results confirm the existence of a marked spatial heterogeneity of malaria transmission in Bandiagara, providing support for implementation of targeted interventions.
Collapse
Affiliation(s)
- Drissa Coulibaly
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | | | - Mark Travassos
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Youssouf Tolo
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Matthew Laurens
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Abdoulaye K Kone
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Karim Traore
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Ando Guindo
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Issa Diarra
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Amadou Niangaly
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Modibo Daou
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Ahmadou Dembele
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Mody Sissoko
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Bourema Kouriba
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Nadine Dessay
- Institut de Recherche pour le Développement, Montpellier, France
| | | | | | - Mahamadou A Thera
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| | - Christopher V Plowe
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ogobara K Doumbo
- Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technologies of Bamako, Point G, BP 1805, Bamako, Mali
| |
Collapse
|
16
|
The time distribution of sulfadoxine-pyrimethamine protection from malaria. Bull Math Biol 2012; 74:2733-51. [PMID: 23081725 DOI: 10.1007/s11538-012-9775-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 09/20/2012] [Indexed: 10/27/2022]
Abstract
Sulfadoxine-pyrimethamine (SP) has been one of the most widely used antimalarial treatments world-wide, and is also used prophylactically in vulnerable populations. In this paper, we develop a mathematical model which allows us to infer the time distribution of SP protection from drug-trial data. Fitting our model to data from a controlled field study in Mali, we find that SP provided protection from malaria for an average of 37.9 days in this pediatric population. We demonstrate that the duration of SP protection is not well described by an exponential distribution, and in fact has a much narrower dispersal about the mean; the best-fit standard deviation predicted by our model was only 17.0 days, as opposed to 41.8 days for the exponential model. We estimate the monthly entomological inoculation rate and the basic reproductive number for malaria in this population, and demonstrate that extremely high SP treatment rates would be necessary to maintain an effective reproductive number below one throughout a single rainy season. These results have implications for further efforts to model the impact of SP treatment, or for investigations of the optimal timing of prophylactic SP.
Collapse
|
17
|
Severe and uncomplicated falciparum malaria in children from three regions and three ethnic groups in Cameroon: prospective study. Malar J 2012; 11:215. [PMID: 22727184 PMCID: PMC3445823 DOI: 10.1186/1475-2875-11-215] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 06/05/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND To identify the factors that account for differences in clinical outcomes of malaria as well as its relationship with ethnicity, transmission intensity and parasite density. METHODS A prospective study was conducted in nine health facilities in the Centre, Littoral and South West regions of Cameroon, and in three ethnic groups; the Bantu, Semi-Bantu and Foulbe. Children aged one month to 13 years, with diagnosis suggestive of malaria, were recruited and characterized using the WHO definition for severe and uncomplicated malaria. Malaria parasitaemia was determined by light microscopy, haematological analysis using an automated haematology analyser and glucose level by colorimetric technique. RESULTS Of the febrile children screened, 971 of the febrile children screened fulfilled the inclusion criteria for specific malaria clinical phenotypes. Forty-nine (9.2%) children had cerebral malaria, a feature that was similar across age groups, ethnicity and gender but lower (P < 0.004) in proportion in the Centre (3.1%, 5/163) compared to the Littoral (11.3%, 32/284) and South West (13.6%, 12/88) regions. Severe anaemia was the most frequent severe disease manifestation, 28.0% (248/885), which was similar in proportion across the three ethnic groups but was more prevalent in females, less than 60 months old, and the Centre region. About 20% (53/267) of the participants presented with respiratory distress, a clinical phenotype independent of age, gender and ethnicity, but highest (P < 0.001) in the Centre (55%, 11/20) compared to the Littoral (27.3%, 3/11) and South West (16.5%, 39/236) regions. Uncomplicated malaria constituted 27.7% (255/920) of hospital admissions and was similar in proportion with gender and across the three ethnic groups but more prevalent in older children (≥ 60 months) as well as in the South West region. The density of malaria parasitaemia was generally similar across clinical groups, gender and ethnicity. However, younger children and residents of the Centre region carried significantly higher parasite loads, with the burden heavier in the Semi-Bantu compared to their Bantu (P = 0.009) and Foulbe (P = 0.026) counterparts in the Centre region. The overall study case fatality was 4.8 (47/755), with cerebral malaria being the only significant risk factor associated with death. Severe anaemia, though a common and major clinical presentation, was not significantly associated with risk of death. CONCLUSION About half of the acutely febrile children presented with severe malaria, the majority being cases of severe malaria anaemia, followed by respiratory distress and cerebral malaria. The latter two were less prevalent in the Centre region compared to the other regions. Cerebral malaria and hyperpyrexia were the only significant risk factors associated with death.
Collapse
|
18
|
Lyke KE, Fernández-Viňa MA, Cao K, Hollenbach J, Coulibaly D, Kone AK, Guindo A, Burdett LA, Hartzman RJ, Wahl AR, Hildebrand WH, Doumbo OK, Plowe CV, Sztein MB. Association of HLA alleles with Plasmodium falciparum severity in Malian children. ACTA ACUST UNITED AC 2011; 77:562-71. [PMID: 21447146 PMCID: PMC3152196 DOI: 10.1111/j.1399-0039.2011.01661.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pre-erythrocytic immunity to Plasmodium falciparum malaria is likely to be mediated by T-cell recognition of malaria epitopes presented on infected host cells via class I and II major histocompatibility complex (MHC) antigens. To test for associations of human leukocyte antigen (HLA) alleles with disease severity, we performed high-resolution typing of HLA class I and II loci and compared the distributions of alleles of HLA-A, -B, -C and -DRB1 loci in 359 Malian children of Dogon ethnicity with uncomplicated or severe malaria. We observed that alleles A*30:01 and A*33:01 had higher frequency in the group of patients with cerebral disease compared to patients with uncomplicated disease [A*30:01: gf = 0.2031 vs gf = 0.1064, odds ratio (OR) = 3.17, P = 0.004, confidence interval (CI) (1.94-5.19)] and [A*33:01: gf = 0.0781 vs gf = 0.0266, 4.21, P = 0.005, CI (1.89-9.84)], respectively. The A*30:01 and A*33:01 alleles share some sequence motifs and A*30:01 appears to have a unique peptide binding repertoire compared to other A*30 group alleles. Computer algorithms predicted malaria peptides with strong binding affinity for HLA-A*30:01 and HLA-A*33:01 but not to closely related alleles. In conclusion, we identified A*30:01 and A*33:01 as potential susceptibility factors for cerebral malaria, providing further evidence that polymorphism of MHC genes results in altered malaria susceptibility.
Collapse
Affiliation(s)
- K E Lyke
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Takala SL, Coulibaly D, Thera MA, Batchelor AH, Cummings MP, Escalante AA, Ouattara A, Traoré K, Niangaly A, Djimdé AA, Doumbo OK, Plowe CV. Extreme polymorphism in a vaccine antigen and risk of clinical malaria: implications for vaccine development. Sci Transl Med 2010; 1:2ra5. [PMID: 20165550 DOI: 10.1126/scitranslmed.3000257] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Vaccines directed against the blood stages of Plasmodium falciparum malaria are intended to prevent the parasite from invading and replicating within host cells. No blood-stage malaria vaccine has shown clinical efficacy in humans. Most malaria vaccine antigens are parasite surface proteins that have evolved extensive genetic diversity, and this diversity could allow malaria parasites to escape vaccine-induced immunity. We examined the extent and within-host dynamics of genetic diversity in the blood-stage malaria vaccine antigen apical membrane antigen-1 in a longitudinal study in Mali. Two hundred and fourteen unique apical membrane antigen-1 haplotypes were identified among 506 human infections, and amino acid changes near a putative invasion machinery binding site were strongly associated with the development of clinical symptoms, suggesting that these residues may be important to consider in designing polyvalent apical membrane antigen-1 vaccines and in assessing vaccine efficacy in field trials. This extreme diversity may pose a serious obstacle to an effective polyvalent recombinant subunit apical membrane antigen-1 vaccine.
Collapse
Affiliation(s)
- Shannon L Takala
- Howard Hughes Medical Institute and Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD 21201, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Thera MA, Doumbo OK, Coulibaly D, Laurens MB, Kone AK, Guindo AB, Traore K, Sissoko M, Diallo DA, Diarra I, Kouriba B, Daou M, Dolo A, Baby M, Sissoko MS, Sagara I, Niangaly A, Traore I, Olotu A, Godeaux O, Leach A, Dubois MC, Ballou WR, Cohen J, Thompson D, Dube T, Soisson L, Diggs CL, Takala SL, Lyke KE, House B, Lanar DE, Dutta S, Heppner DG, Plowe CV. Safety and immunogenicity of an AMA1 malaria vaccine in Malian children: results of a phase 1 randomized controlled trial. PLoS One 2010; 5:e9041. [PMID: 20140214 PMCID: PMC2816207 DOI: 10.1371/journal.pone.0009041] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 01/07/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The objective was to evaluate the safety and immunogenicity of the AMA1-based malaria vaccine FMP2.1/AS02(A) in children exposed to seasonal falciparum malaria. METHODOLOGY/PRINCIPAL FINDINGS A Phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02(A) is a recombinant protein (FMP2.1) based on apical membrane antigen 1 (AMA1) from the 3D7 clone of P. falciparum, formulated in the Adjuvant System AS02(A). The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert). One hundred healthy Malian children aged 1-6 years were recruited into 3 cohorts and randomized to receive either 10 microg FMP2.1 in 0.1 mL AS02(A), or 25 microg FMP2.1 in 0.25 mL AS02(A), or 50 microg FMP2.1 50 microg in 0.5 mL AS02(A), or rabies vaccine. Three doses of vaccine were given at 0, 1 and 2 months, and children were followed for 1 year. Solicited symptoms were assessed for 7 days and unsolicited symptoms for 30 days after each vaccination. Serious adverse events were assessed throughout the study. Transient local pain and swelling were common and more frequent in all malaria vaccine dosage groups than in the comparator group, but were acceptable to parents of participants. Levels of anti-AMA1 antibodies measured by ELISA increased significantly (at least 100-fold compared to baseline) in all 3 malaria vaccine groups, and remained high during the year of follow up. CONCLUSION/SIGNIFICANCE The FMP2.1/AS02(A) vaccine had a good safety profile, was well-tolerated, and induced high and sustained antibody levels in malaria-exposed children. This malaria vaccine is being evaluated in a Phase 2 efficacy trial in children at this site. TRIAL REGISTRATION ClinicalTrials.gov NCT00358332 [NCT00358332].
Collapse
Affiliation(s)
- Mahamadou A. Thera
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Ogobara K. Doumbo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Matthew B. Laurens
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Abdoulaye K. Kone
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Ando B. Guindo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Karim Traore
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Mady Sissoko
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Dapa A. Diallo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Issa Diarra
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Bourema Kouriba
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Modibo Daou
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Amagana Dolo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Mounirou Baby
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | | | - Issaka Sagara
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Amadou Niangaly
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Idrissa Traore
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Ally Olotu
- GlaxoSmithKline Biologicals, Rixensart, Belgium
| | | | | | | | | | - Joe Cohen
- GlaxoSmithKline Biologicals, Rixensart, Belgium
| | - Darby Thompson
- EMMES Corporation, Rockville, Maryland, United States of America
| | - Tina Dube
- EMMES Corporation, Rockville, Maryland, United States of America
| | - Lorraine Soisson
- Malaria Vaccine Development Program, U.S. Agency for International Development, Washington, D.C., United States of America
| | - Carter L. Diggs
- Malaria Vaccine Development Program, U.S. Agency for International Development, Washington, D.C., United States of America
| | - Shannon L. Takala
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Kirsten E. Lyke
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Brent House
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - David E. Lanar
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Sheetij Dutta
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - D. Gray Heppner
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Christopher V. Plowe
- Howard Hughes Medical Institute/Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| |
Collapse
|
21
|
Doumbo OK, Thera MA, Koné AK, Raza A, Tempest LJ, Lyke KE, Plowe CV, Rowe JA. High levels of Plasmodium falciparum rosetting in all clinical forms of severe malaria in African children. Am J Trop Med Hyg 2009; 81:987-93. [PMID: 19996426 PMCID: PMC2877664 DOI: 10.4269/ajtmh.2009.09-0406] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Plasmodium falciparum rosetting (the spontaneous binding of infected erythrocytes to uninfected erythrocytes) is a well-recognized parasite virulence factor. However, it is currently unclear whether rosetting is associated with all clinical forms of severe malaria, or only with specific syndromes such as cerebral malaria. We investigated the relationship between rosetting and clinical malaria in 209 Malian children enrolled in a case-control study of severe malaria. Rosetting was significantly higher in parasite isolates from severe malaria cases compared with non-severe hyperparasitemia and uncomplicated malaria controls (F(2,117) = 8.15, P < 0.001). Analysis of sub-categories of severe malaria (unrousable coma, severe anemia, non-comatose neurological impairment, repeated seizures or a small heterogeneous group with signs of renal failure or jaundice) showed high levels of rosetting in all sub-categories, and no statistically significant differences in rosetting between sub-categories (F(4,67) = 1.28, P = 0.28). Thus rosetting may contribute to the pathogenesis of all severe malaria syndromes in African children, and interventions to disrupt rosetting could be potential adjunctive therapies for all forms of severe malaria in Africa.
Collapse
Affiliation(s)
- Ogobara K Doumbo
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Mali.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Sagara I, Dicko A, Ellis RD, Fay MP, Diawara SI, Assadou MH, Sissoko MS, Kone M, Diallo AI, Saye R, Guindo MA, Kante O, Niambele MB, Miura K, Mullen GED, Pierce M, Martin LB, Dolo A, Diallo DA, Doumbo OK, Miller LH, Saul A. A randomized controlled phase 2 trial of the blood stage AMA1-C1/Alhydrogel malaria vaccine in children in Mali. Vaccine 2009; 27:3090-8. [PMID: 19428923 DOI: 10.1016/j.vaccine.2009.03.014] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 02/26/2009] [Accepted: 03/05/2009] [Indexed: 11/18/2022]
Abstract
A double blind, randomized, controlled Phase 2 clinical trial was conducted to assess the safety, immunogenicity, and biologic impact of the vaccine candidate Apical Membrane Antigen 1-Combination 1 (AMA1-C1), adjuvanted with Alhydrogel. Participants were healthy children 2-3 years old living in or near the village of Bancoumana, Mali. A total of 300 children received either the study vaccine or the comparator. No impact of vaccination was seen on the primary endpoint, the frequency of parasitemia measured as episodes >3000/microL/day at risk. There was a negative impact of vaccination on the hemoglobin level during clinical malaria, and mean incidence of hemoglobin <8.5 g/dL, in the direction of lower hemoglobin in the children who received AMA1-C1, although these differences were not significant after correction for multiple tests. These differences were not seen in the second year of transmission.
Collapse
Affiliation(s)
- Issaka Sagara
- Malaria Research and Training Center, Faculty of Medicine Pharmacy and Dentistry BP 1805 Bamako, University of Bamako, Mali, Malaysia.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Moorthy VS, Reed Z, Smith PG. Clinical trials to estimate the efficacy of preventive interventions against malaria in paediatric populations: a methodological review. Malar J 2009; 8:23. [PMID: 19208236 PMCID: PMC2646744 DOI: 10.1186/1475-2875-8-23] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Accepted: 02/10/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent years have seen publication of a considerable number of clinical trials of preventive interventions against clinical malaria in children. There has been variability in the specification of end-points, case definitions, analysis methods and reporting and the relative lack of standardization complicates the ability to make comparative evaluations between trials. METHODS To prepare for a WHO consultation on design issues in malaria vaccine trials, controlled trials of preventive interventions against malaria in children in endemic countries were identified in which clinical malaria, or death, had been one of the main end-points. Trials were included that evaluated the impact of vaccines, insecticide-treated bed nets (ITN), intermittent presumptive or preventive therapy in infants (IPTi) or, in one instance, vitamin A supplementation. Methods that had been used in these trials were summarized and compared in order to identify issues that were directly relevant to the design of malaria vaccine trials. RESULTS 29 controlled trials of preventive malaria interventions were identified, of which eight were vaccine trials. Vaccine trials that were designed to detect an effect on clinical malaria all reported the incidence rate of first episodes of clinical malaria as their primary endpoint. Only one trial of a preventive intervention (of ITN) was identified that was designed to detect an effect on severe malaria. A group of larger trials were designed to detect an effect of impregnated bed nets or curtains on all-cause mortality as the primary end-point. Key methodological and reporting differences between trials are noted in the text. Two issues have been identified that are of some concern. Firstly, the choice of primary endpoint is not stated in the reports of a number of the trials and, secondly, the relationship between pre-specified analysis plans and trial reports is rarely made clear. CONCLUSION This article reports an investigation into the ways in which trial design and reporting could be improved and standardized to enable comparative evaluation of the relative merits of malaria control measures, and specifically with respect to the design of malaria vaccine trials. The need for standardization of clinical trial design, conduct, analysis and reporting has been also affirmed as a priority area by the Malaria Vaccine Technology Roadmap.
Collapse
Affiliation(s)
- Vasee S Moorthy
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
| | | | | |
Collapse
|
24
|
Lyke KE, Daou M, Diarra I, Kone A, Kouriba B, Thera MA, Dutta S, Lanar DE, Heppner DG, Doumbo OK, Plowe CV, Sztein MB. Cell-mediated immunity elicited by the blood stage malaria vaccine apical membrane antigen 1 in Malian adults: results of a Phase I randomized trial. Vaccine 2009; 27:2171-6. [PMID: 19356621 DOI: 10.1016/j.vaccine.2009.01.097] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 01/19/2009] [Accepted: 01/22/2009] [Indexed: 10/21/2022]
Abstract
The development of a safe and effective malaria vaccine is impeded by the complexity of the Plasmodium life cycle. A vaccine that elicits both cell-mediated and humoral immune responses might be needed for protection against this multistage parasitic infection. Apical membrane antigen 1 (AMA-1) plays a key role in erythrocytic invasion but is also expressed in sporozoites and in late stage liver schizonts, where it may provide a target of protective cell-mediated immunity (CMI). A Phase 1 trial of a vaccine consisting of recombinant AMA-1 protein and the Adjuvant system AS02A was conducted in 60 Malian adults aged 18-55 years who were randomized to receive either half-dose (25 microg/0.25 ml) or full dose (50 microg/0.5 ml) FMP2.1/AS02A or a control rabies vaccine. Interleukin 5 (IL-5) and interferon-gamma (IFN-gamma) production as evaluated by ELISpot and lymphocyte proliferation were measured after in vitro AMA-1 stimulation of peripheral blood mononuclear cells (PBMCs) collected on Days 0 and 90. Post-FMP2.1/AS02A immunization mean stimulation indices were significantly elevated as were the number of IL-5 spot forming cells (SFC)/10(6) PBMC, but no difference was noted in INF-gamma production between the AMA-1/AS02A vaccinated group and the rabies group. These results provide evidence that complex immune responses can be induced by this vaccination strategy and add further impetus for the continuing clinical evaluation of this vaccine.
Collapse
Affiliation(s)
- Kirsten E Lyke
- Center for Vaccine Development, University of Maryland, Baltimore, MD, United States.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Dicko A, Sagara I, Sissoko MS, Guindo O, Diallo AI, Kone M, Toure OB, Sacko M, Doumbo OK. Impact of intermittent preventive treatment with sulphadoxine-pyrimethamine targeting the transmission season on the incidence of clinical malaria in children in Mali. Malar J 2008; 7:123. [PMID: 18611271 PMCID: PMC2500037 DOI: 10.1186/1475-2875-7-123] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Accepted: 07/08/2008] [Indexed: 11/28/2022] Open
Abstract
Background Recent studies have shown that intermittent preventive malaria treatment (IPT) in infants in areas of stable malaria transmission reduces malaria and severe anaemia incidence. However in most areas malaria morbidity and mortality remain high in older children. Methods To evaluate the effect of seasonal IPT with sulphadoxine pyrimethamine (SP) on incidence of malaria disease in area of seasonal transmission, 262 children 6 months-10 years in Kambila, Mali were randomized to receive either IPT with SP twice at eight weeks interval or no IPT during the transmission season of 2002 and were followed up for 12 months. Subjects were also followed during the subsequent transmission season in 2003 to assess possible rebound effect. Clinical malaria cases were treated with SP and followed to assess the in vivo response during both periods. Results The incidence rate of malaria disease per 1,000 person-months during the first 12 months was 3.2 episodes in the treatment group vs. 5.8 episodes in the control group with age-adjusted Protective Efficacy (PE) of 42.5%; [95% CI 28.6%–53.8%]. When the first 16 weeks of follow up is considered age-adjusted PE was 67.5% [95% CI 55.3% – 76.6%]. During the subsequent transmission season, the incidence of clinical malaria per 1000 persons-days was similar between the two groups (23.0 vs 21.5 episodes, age-adjusted IRR = 1.07 [95% CI, 0.90–1.27]). No significant difference was detected in in vivo response between the groups during both periods. Conclusion Two malaria intermittent treatments targeting the peak transmission season reduced the annual incidence rate of clinical malaria by 42.5% in an area with intense seasonal transmission. This simple strategy is likely to be one of the most effectives in reducing malaria burden in such areas. Trial Registration Clinicaltrials.gov NCT00623155
Collapse
Affiliation(s)
- Alassane Dicko
- Malaria Research and Training Center, Departments of Epidemiology of Parasitic Diseases, Faculty of Medicine Pharmacy and Dentistry, University of Bamako, P.O. Box 1805, Bamako, Mali.
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Safety and immunogenicity of an AMA-1 malaria vaccine in Malian adults: results of a phase 1 randomized controlled trial. PLoS One 2008; 3:e1465. [PMID: 18213374 PMCID: PMC2186380 DOI: 10.1371/journal.pone.0001465] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 12/17/2007] [Indexed: 11/19/2022] Open
Abstract
Background The objective was to evaluate the safety, reactogenicity and immunogenicity of the AMA-1-based blood-stage malaria vaccine FMP2.1/AS02A in adults exposed to seasonal malaria. Methodology/Principal Findings A phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02A is a recombinant protein (FMP2.1) based on apical membrane antigen-1 (AMA-1) from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert). Sixty healthy, malaria-experienced adults aged 18–55 y were recruited into 2 cohorts and randomized to receive either a half dose or full dose of the malaria vaccine (FMP2.1 25 µg/AS02A 0.25 mL or FMP2.1 50 µg/AS02A 0.5 mL) or rabies vaccine given in 3 doses at 0, 1 and 2 mo, and were followed for 1 y. Solicited symptoms were assessed for 7 d and unsolicited symptoms for 30 d after each vaccination. Serious adverse events were assessed throughout the study. Titers of anti-AMA-1 antibodies were measured by ELISA and P. falciparum growth inhibition assays were performed on sera collected at pre- and post-vaccination time points. Transient local pain and swelling were common and more frequent in both malaria vaccine dosage groups than in the comparator group. Anti-AMA-1 antibodies increased significantly in both malaria vaccine groups, peaking at nearly 5-fold and more than 6-fold higher than baseline in the half-dose and full-dose groups, respectively. Conclusion/Significance The FMP2.1/AS02A vaccine had a good safety profile, was well-tolerated, and was highly immunogenic in malaria-exposed adults. This malaria vaccine is being evaluated in Phase 1 and 2 trials in children at this site. Trial Registration ClinicalTrials.gov NCT00308061
Collapse
|
27
|
Blood group O protects against severe Plasmodium falciparum malaria through the mechanism of reduced rosetting. Proc Natl Acad Sci U S A 2007; 104:17471-6. [PMID: 17959777 DOI: 10.1073/pnas.0705390104] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Malaria has been a major selective force on the human population, and several erythrocyte polymorphisms have evolved that confer resistance to severe malaria. Plasmodium falciparum rosetting, a parasite virulence phenotype associated with severe malaria, is reduced in blood group O erythrocytes compared with groups A, B, and AB, but the contribution of the ABO blood group system to protection against severe malaria has received little attention. We hypothesized that blood group O may confer resistance to severe falciparum malaria through the mechanism of reduced rosetting. In a matched case-control study of 567 Malian children, we found that group O was present in only 21% of severe malaria cases compared with 44-45% of uncomplicated malaria controls and healthy controls. Group O was associated with a 66% reduction in the odds of developing severe malaria compared with the non-O blood groups (odds ratio 0.34, 95% confidence interval 0.19-0.61, P < 0.0005, severe cases versus uncomplicated malaria controls). In the same sample set, P. falciparum rosetting was reduced in parasite isolates from group O children compared with isolates from the non-O blood groups (P = 0.003, Kruskal-Wallis test). Statistical analysis indicated a significant interaction between host ABO blood group and parasite rosette frequency that supports the hypothesis that the protective effect of group O operates through the mechanism of reduced P. falciparum rosetting. This work provides insights into malaria pathogenesis and suggests that the selective pressure imposed by malaria may contribute to the variable global distribution of ABO blood groups in the human population.
Collapse
|
28
|
Ngoungou EB, Poudiougou B, Dulac O, Dicko A, Boncoeur MP, Traoré AM, Coulibaly D, Keita MM, Preux PM, Doumbo OK, Druet-Cabanac M. [Persistent neurological sequelae due to cerebral malaria in a cohort of children from Mali]. Rev Neurol (Paris) 2007; 163:583-8. [PMID: 17571026 DOI: 10.1016/s0035-3787(07)90464-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Several neurological complications are associated with cerebral malaria (CM). However, few long-term data from childhood survivors have been published. METHODS A cross-sectional study was carried out in Mali among children followed from 1999 to 2002 after serious and complicated malaria. Our aim was to evaluate the persistent neurological sequelae associated with CM. RESULTS This study concerned 101 subjects who had had CM. Mean age was 5.6+/-3.6 years. Twenty-eight children presented persistent neurological sequelae (27.7p.cent). Among them eight (7.9p.cent) children had developed these sequelae just after CM and 20 (19.8p.cent) a few months later: headaches, mental retardation, speech delay, bucco-facial dyspraxia, diplegia and frontal syndrome (one case each), dystonia (two cases), epilepsy (five cases) and behavior and attention disorders (15 cases). CONCLUSIONS In this study, we show that neurological signs due to CM can persist in the long run. Long-term follow-up and proper management after CM are essential.
Collapse
Affiliation(s)
- E B Ngoungou
- Institut d'Epidémiologie Neurologique et de Neurologie Tropicale (EA 3174), Faculté de Médecine de Limoges, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Oduro AR, Koram KA, Rogers W, Atuguba F, Ansah P, Anyorigiya T, Ansah A, Anto F, Mensah N, Hodgson A, Nkrumah F. Severe falciparum malaria in young children of the Kassena-Nankana district of northern Ghana. Malar J 2007; 6:96. [PMID: 17662142 PMCID: PMC1950879 DOI: 10.1186/1475-2875-6-96] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Accepted: 07/27/2007] [Indexed: 11/22/2022] Open
Abstract
Study design Severe falciparum malaria in children was studied as part of the characterization of the Kassena-Nankana District Ghana for future malaria vaccine trials. Children aged 6–59 months with diagnosis suggestive of acute disease were characterized using the standard WHO definition for severe malaria. Results Of the total children screened, 45.2% (868/1921) satisfied the criteria for severe malaria. Estimated incidence of severe malaria was 3.4% (range: 0.4–8.3%) cases per year. The disease incidence was seasonal: 560 cases per year, of which 70.4% occurred during the wet season (June-October). The main manifestations were severe anaemia (36.5%); prolonged or multiple convulsions (21.6%); respiratory distress (24.4%) and cerebral malaria (5.4%). Others were hyperpyrexia (11.1%); hyperparasitaemia (18.5%); hyperlactaemia (33.4%); and hypoglycaemia (3.2%). The frequency of severe anaemia was 39.8% in children of six to 24 months of age and 25.9% in children of 25–60 months of age. More children (8.7%) in the 25–60 months age group had cerebral malaria compared with 4.4% in the 6–24 months age group. The overall case fatality ratio was 3.5%. Cerebral malaria and hyperlactataemia were the significant risk factors associated with death. Severe anaemia, though a major presentation, was not significantly associated with risk of death. Conclusion Severe malaria is a frequent and seasonal childhood disease in northern Ghana and maybe an adequate endpoint for future malaria vaccine trials.
Collapse
Affiliation(s)
- Abraham R Oduro
- Navrongo Health Research Centre, P.O. Box 114, Navrongo, Ghana
| | - Kwadwo A Koram
- Noguchi Memorial Institute for Medical Research, UG, Box 25, Legon, Accra, Ghana
| | - William Rogers
- Naval Medical Research Centre, Malaria Program, Silver Spring, Maryland, USA
| | - Frank Atuguba
- Navrongo Health Research Centre, P.O. Box 114, Navrongo, Ghana
| | - Patrick Ansah
- Navrongo Health Research Centre, P.O. Box 114, Navrongo, Ghana
| | | | - Akosua Ansah
- Navrongo Health Research Centre, P.O. Box 114, Navrongo, Ghana
| | - Francis Anto
- Navrongo Health Research Centre, P.O. Box 114, Navrongo, Ghana
| | - Nathan Mensah
- Navrongo Health Research Centre, P.O. Box 114, Navrongo, Ghana
| | - Abraham Hodgson
- Navrongo Health Research Centre, P.O. Box 114, Navrongo, Ghana
| | - Francis Nkrumah
- Noguchi Memorial Institute for Medical Research, UG, Box 25, Legon, Accra, Ghana
| |
Collapse
|
30
|
Takala SL, Coulibaly D, Thera MA, Dicko A, Smith DL, Guindo AB, Kone AK, Traore K, Ouattara A, Djimde AA, Sehdev PS, Lyke KE, Diallo DA, Doumbo OK, Plowe CV. Dynamics of polymorphism in a malaria vaccine antigen at a vaccine-testing site in Mali. PLoS Med 2007; 4:e93. [PMID: 17355170 PMCID: PMC1820605 DOI: 10.1371/journal.pmed.0040093] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 01/16/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Malaria vaccines based on the 19-kDa region of merozoite surface protein 1 (MSP-1(19)) derived from the 3D7 strain of Plasmodium falciparum are being tested in clinical trials in Africa. Knowledge of the distribution and natural dynamics of vaccine antigen polymorphisms in populations in which malaria vaccines will be tested will guide vaccine design and permit distinction between natural fluctuations in genetic diversity and vaccine-induced selection. METHODS AND FINDINGS Using pyrosequencing, six single-nucleotide polymorphisms in the nucleotide sequence encoding MSP-1(19) were genotyped from 1,363 malaria infections experienced by 100 children who participated in a prospective cohort study in Mali from 1999 to 2001. The frequencies of 14 MSP-1(19) haplotypes were compared over the course of the malaria transmission season for all three years, in three age groups, and in consecutive infections within individuals. While the frequency of individual MSP-1(19) haplotypes fluctuated, haplotypes corresponding to FVO and FUP strains of P. falciparum (MSP-1(19) haplotypes QKSNGL and EKSNGL, respectively) were most prevalent during three consecutive years and in all age groups with overall prevalences of 46% (95% confidence interval [CI] 44%-49%) and 36% (95% CI 34%-39%), respectively. The 3D7 haplotype had a lower overall prevalence of 16% (95% CI 14%-18%). Multiplicity of infection based on MSP-1(19) was higher at the beginning of the transmission season and in the oldest individuals (aged > or =11 y). Three MSP-1(19) haplotypes had a reduced frequency in symptomatic infections compared to asymptomatic infections. Analyses of the dynamics of MSP-1(19) polymorphisms in consecutive infections implicate three polymorphisms (at positions 1691, 1700, and 1701) as being particularly important in determining allele specificity of anti-MSP-1(19) immunity. CONCLUSIONS Parasites with MSP-1(19) haplotypes different from that of the leading vaccine strain were consistently the most prevalent at a vaccine trial site. If immunity elicited by an MSP-1-based vaccine is allele-specific, a vaccine based on either the FVO or FUP strain might have better initial efficacy at this site. This study, to our knowledge the largest of its kind to date, provides molecular information needed to interpret population responses to MSP-1-based vaccines and suggests that certain MSP-1(19) polymorphisms may be relevant to cross-protective immunity.
Collapse
Affiliation(s)
- Shannon L Takala
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Mahamadou A Thera
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Alassane Dicko
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - David L Smith
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ando B Guindo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Abdoulaye K Kone
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Karim Traore
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Amed Ouattara
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Abdoulaye A Djimde
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Paul S Sehdev
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Kirsten E Lyke
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Dapa A Diallo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Ogobara K Doumbo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Christopher V Plowe
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
31
|
Thera MA, Doumbo OK, Coulibaly D, Diallo DA, Sagara I, Dicko A, Diemert DJ, Heppner DG, Stewart VA, Angov E, Soisson L, Leach A, Tucker K, Lyke KE, Plowe CV. Safety and allele-specific immunogenicity of a malaria vaccine in Malian adults: results of a phase I randomized trial. PLOS CLINICAL TRIALS 2006; 1:e34. [PMID: 17124530 PMCID: PMC1851722 DOI: 10.1371/journal.pctr.0010034] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Accepted: 10/10/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVES The objectives were to evaluate the safety, reactogenicity, and allele-specific immunogenicity of the blood-stage malaria vaccine FMP1/AS02A in adults exposed to seasonal malaria and the impact of natural infection on vaccine-induced antibody levels. DESIGN We conducted a randomized, double-blind, controlled phase I clinical trial. SETTING Bandiagara, Mali, West Africa, is a rural town with intense seasonal transmission of Plasmodium falciparum malaria. PARTICIPANTS Forty healthy, malaria-experienced Malian adults aged 18-55 y were enrolled. INTERVENTIONS The FMP1/AS02A malaria vaccine is a 42-kDa recombinant protein based on the carboxy-terminal end of merozoite surface protein-1 (MSP-1(42)) from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The control vaccine was a killed rabies virus vaccine (Imovax). Participants were randomized to receive either FMP1/AS02A or rabies vaccine at 0, 1, and 2 mo and were followed for 1 y. OUTCOME MEASURES Solicited and unsolicited adverse events and allele-specific antibody responses to recombinant MSP-1(42) and its subunits derived from P. falciparum strains homologous and heterologous to the 3D7 vaccine strain were measured. RESULTS Transient local pain and swelling were more common in the malaria vaccine group than in the control group (11/20 versus 3/20 and 10/20 versus 6/20, respectively). MSP-1(42) antibody levels rose during the malaria transmission season in the control group, but were significantly higher in malaria vaccine recipients after the second immunization and remained higher after the third immunization relative both to baseline and to the control group. Immunization with the malaria vaccine was followed by significant increases in antibodies recognizing three diverse MSP-1(42) alleles and their subunits. CONCLUSIONS FMP1/AS02A was well tolerated and highly immunogenic in adults exposed to intense seasonal malaria transmission and elicited immune responses to genetically diverse parasite clones. Anti-MSP-1(42) antibody levels followed a seasonal pattern that was significantly augmented and prolonged by the malaria vaccine.
Collapse
Affiliation(s)
- Mahamadou A Thera
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Ogobara K Doumbo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Dapa A Diallo
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Issaka Sagara
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - Alassane Dicko
- Malaria Research and Training Center, University of Bamako, Bamako, Mali
| | - David J Diemert
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - D. Gray Heppner
- Department of Immunology, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - V. Ann Stewart
- Department of Immunology, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Evelina Angov
- Department of Immunology, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Lorraine Soisson
- United States Agency for International Development, Washington, D. C., United States of America
| | | | - Kathryn Tucker
- Statistics Collaborative, Washington, D. C., United States of America
| | - Kirsten E Lyke
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Christopher V Plowe
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail:
| | | |
Collapse
|
32
|
Kyriacou HM, Stone GN, Challis RJ, Raza A, Lyke KE, Thera MA, Koné AK, Doumbo OK, Plowe CV, Rowe JA. Differential var gene transcription in Plasmodium falciparum isolates from patients with cerebral malaria compared to hyperparasitaemia. Mol Biochem Parasitol 2006; 150:211-8. [PMID: 16996149 PMCID: PMC2176080 DOI: 10.1016/j.molbiopara.2006.08.005] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 08/04/2006] [Accepted: 08/08/2006] [Indexed: 11/13/2022]
Abstract
The Plasmodium falciparum variant erythrocyte surface antigens known as PfEMP1, encoded by the var gene family, are thought to play a crucial role in malaria pathogenesis because they mediate adhesion to host cells and immuno-modulation. Var genes have been divided into three major groups (A, B and C) and two intermediate groups (B/A and B/C) on the basis of their genomic location and upstream sequence. We analysed expressed sequence tags of the var gene DBLα domain to investigate var gene transcription in relation to disease severity in Malian children. We found that P. falciparum isolates from children with cerebral malaria (unrousable coma) predominantly transcribe var genes with DBLα1-like domains that are characteristic of Group A or B/A var genes. In contrast, isolates from children with equally high parasite burdens but no symptoms or signs of severe malaria (hyperparasitaemia patients) predominantly transcribe var genes with DBLα0-like domains that are characteristic of the B and C-related var gene groups. These results suggest that var genes with DBLα1-like domains (Group A or B/A) may be implicated in the pathogenesis of cerebral malaria, while var genes with DBLα0-like domains promote less virulent malaria infections.
Collapse
Affiliation(s)
- Helen M. Kyriacou
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Graham N. Stone
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Richard J. Challis
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Ahmed Raza
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Kirsten E. Lyke
- University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mahamadou A. Thera
- Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, BP 1805, Mali
| | - Abdoulaye K. Koné
- Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, BP 1805, Mali
| | - Ogobara K. Doumbo
- Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, BP 1805, Mali
| | | | - J. Alexandra Rowe
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
- Corresponding address: Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK. Tel.: +44 131 650 5492; fax: +44 131 650 6564.
| |
Collapse
|
33
|
Ngoungou EB, Dulac O, Poudiougou B, Druet-Cabanac M, Dicko A, Mamadou Traore A, Coulibaly D, Farnarier G, Tuillas M, Keita MM, Kombila M, Doumbo OK, Preux PM. Epilepsy as a Consequence of Cerebral Malaria in Area in Which Malaria Is Endemic in Mali, West Africa. Epilepsia 2006. [DOI: 10.1111/j.0013-9580.2006.00558.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
34
|
Ngoungou EB, Dulac O, Poudiougou B, Druet-Cabanac M, Dicko A, Mamadou Traore A, Coulibaly D, Farnarier G, Tuillas M, Keita MM, Kombila M, Doumbo OK, Preux PM. Epilepsy as a Consequence of Cerebral Malaria in Area in Which Malaria Is Endemic in Mali, West Africa. Epilepsia 2006. [DOI: 10.1111/j.1528-1167.2006.00524.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
35
|
Takala SL, Smith DL, Stine OC, Coulibaly D, Thera MA, Doumbo OK, Plowe CV. A high-throughput method for quantifying alleles and haplotypes of the malaria vaccine candidate Plasmodium falciparum merozoite surface protein-1 19 kDa. Malar J 2006; 5:31. [PMID: 16626494 PMCID: PMC1459863 DOI: 10.1186/1475-2875-5-31] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Accepted: 04/20/2006] [Indexed: 11/12/2022] Open
Abstract
Background Malaria vaccine efficacy may be compromised if the frequency of non-target alleles increases following vaccination with a genetically polymorphic target. Methods are needed to monitor genetic diversity in polymorphic vaccine antigens, but determining which genetic variants of such antigens are present in infected individuals is complicated by the frequent occurrence of mixed infections. Methods Pyrosequencing was used to determine allele frequencies at each of six single nucleotide polymorphisms in the Plasmodium falciparum blood-stage vaccine antigen merozoite surface protein 1 19 kDa (MSP-119) in field samples from a vaccine-testing site in Mali. Mixtures of MSP-119 clones were created to validate a haplotype-estimating algorithm that uses maximum likelihood methods to determine the most probable combination of haplotypes given the allele frequencies for an infection and the haplotypes known to be circulating in the population. Results Fourteen unique MSP-119 haplotypes were identified among 351 genotyped infections. After adjustment to a standard curve, Pyrosequencing provided accurate and precise estimates of allele frequencies in mixed infections. The haplotype-estimating algorithm provided accurate estimates of haplotypes in mixed infections containing up to three haplotypes. Based on the MSP-119 locus, approximately 90% of the 351 infections contained two or fewer haplotypes. Conclusion Pyrosequencing in conjunction with a haplotype-estimating algorithm provides accurate estimates of haplotypes present in infections with up to 3 haplotypes, and can be used to monitor genetic diversity in parasite populations prior to and following introduction of MSP-1-based malaria vaccines.
Collapse
Affiliation(s)
- Shannon L Takala
- Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, HSF1-480, Baltimore, Maryland 21201, USA
| | - David L Smith
- Fogarty International Center, National Institutes of Health, 16 Center Drive, Room 202, Bethesda, Maryland 20892, USA
| | - O Colin Stine
- Department of Epidemiology and Preventive Medicine, 660 West Redwood Street, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Bamako, BP 1805, Bamako, Mali
| | - Mahamadou A Thera
- Malaria Research and Training Center, University of Bamako, BP 1805, Bamako, Mali
| | - Ogobara K Doumbo
- Malaria Research and Training Center, University of Bamako, BP 1805, Bamako, Mali
| | - Christopher V Plowe
- Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, HSF1-480, Baltimore, Maryland 21201, USA
| |
Collapse
|
36
|
Wilson ME. Malaria vaccine trial: Modest protection, good progress. Curr Infect Dis Rep 2005; 7:31-32. [PMID: 15610668 DOI: 10.1007/s11908-005-0020-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
37
|
Affiliation(s)
- Philippe Van de Perre
- Laboratories of Bacteriology and Virology, University Hospital of Montpellier, 34395-Montpellier Cedex 5, France.
| | | |
Collapse
|