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Ogwang R, Murugu L, Nkumama IN, Nyamako L, Kai O, Mwai K, Murungi L, Idro R, Bejon P, Tuju J, Kinyanjui SM, Osier FHA. Bi-isotype immunoglobulins enhance antibody-mediated neutrophil activity against Plasmodium falciparum parasites. Front Immunol 2024; 15:1360220. [PMID: 38650925 PMCID: PMC11033408 DOI: 10.3389/fimmu.2024.1360220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/19/2024] [Indexed: 04/25/2024] Open
Abstract
Background Malaria remains a major global health priority, and monoclonal antibodies (mAbs) are emerging as potential new tools to support efforts to control the disease. Recent data suggest that Fc-dependent mechanisms of immunity are important mediators of protection against the blood stages of the infection, but few studies have investigated this in the context of mAbs. We aimed to isolate mAbs agnostic to cognate antigens that target whole merozoites and simultaneously induce potent neutrophil activity measured by the level of reactive oxygen species (ROS) production using an antibody-dependent respiratory burst (ADRB) assay. Methods We used samples from semi-immune adults living in coastal Kenya to isolate mAbs that induce merozoite-specific ADRB activity. We then tested whether modifying the expressed IgG1 isotype to an IgG-IgA Fc region chimera would enhance the level of ADRB activity. Results We isolated a panel of nine mAbs with specificity to whole merozoites. mAb J31 induced ADRB activity in a dose-dependent fashion. Compared to IgG1, our modified antibody IgG-IgA bi-isotype induced higher ADRB activity across all concentrations tested. Further, we observed a negative hook effect at high IgG1 mAb concentrations (i.e., >200 µg/mL), but this was reversed by Fc modification. We identified MSP3.5 as the potential cognate target of mAb J31. Conclusions We demonstrate an approach to engineer mAbs with enhanced ADRB potency against blood-stage parasites.
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Affiliation(s)
- Rodney Ogwang
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Lewis Murugu
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, Pwani University, Kilifi, Kenya
| | - Irene N. Nkumama
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Lydia Nyamako
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Oscar Kai
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kennedy Mwai
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Linda Murungi
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Richard Idro
- College of Health Sciences, Makerere University, Kampala, Uganda
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Philip Bejon
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - James Tuju
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, Pwani University, Kilifi, Kenya
| | - Sam Muchina Kinyanjui
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Faith H. A. Osier
- Department of Life Sciences, Imperial College London, London, United Kingdom
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2
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Mutemi DD, Tuju J, Ogwang R, Nyamako L, Wambui KM, Cruz IR, Villner P, Yman V, Kinyanjui SM, Rooth I, Ngasala B, Färnert A, Osier FHA. Antibody-Dependent Respiratory Burst against Plasmodium falciparum Merozoites in Individuals Living in an Area with Declining Malaria Transmission. Vaccines (Basel) 2024; 12:203. [PMID: 38400186 PMCID: PMC10892224 DOI: 10.3390/vaccines12020203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/07/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
Malaria transmission intensity affects the development of naturally acquired immunity to malaria. An absolute correlate measure of protection against malaria is lacking. However, antibody-mediated functions against Plasmodium falciparum correlate with protection against malaria. In children, antibody-mediated functions against P. falciparum decline with reduced exposure. It is unclear whether adults maintain antibody-mediated functions as malaria transmission declines. This study assessed antibody-dependent respiratory burst (ADRB) in individuals from an area with declining malaria transmission. In an age-matched analysis, we compare ADRB activity during high versus low malaria transmission periods. Age significantly predicted higher ADRB activity in the high (p < 0.001) and low (p < 0.001) malaria transmission periods. ADRB activity was higher during the high compared to the low malaria transmission period in older children and adults. Only older adults during the high malaria transmission period had their median ADRB activity above the ADRB cut-off. Ongoing P. falciparum infection influenced ADRB activity during the low (p = 0.01) but not the high (p = 0.29) malaria transmission period. These findings propose that naturally acquired immunity to P. falciparum is affected in children and adults as malaria transmission declines, implying that vaccines will be necessary to induce and maintain protection against malaria.
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Affiliation(s)
- Doreen D. Mutemi
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, 171 77 Stockholm, Sweden
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam 11102, Tanzania
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi 80108, Kenya
| | - James Tuju
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi 80108, Kenya
| | - Rodney Ogwang
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi 80108, Kenya
| | - Lydia Nyamako
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi 80108, Kenya
| | - Kennedy M. Wambui
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi 80108, Kenya
- Epidemiology and Biostatistics Division, School of Public Health, University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Ivette R. Cruz
- Division of Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Pär Villner
- Division of Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Victor Yman
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, 171 77 Stockholm, Sweden
- Department of Infectious Diseases, Södersjukhuset, 118 61 Stockholm, Sweden
| | - Samson M. Kinyanjui
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi 80108, Kenya
- Pwani University Bioscience Research Centre, Pwani University, Kilifi 80108, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7LG, UK
- School of Business Studies, Strathmore University, Nairobi 0200, Kenya
| | - Ingegerd Rooth
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, 171 77 Stockholm, Sweden
- Nyamisati Malaria Research Group, Pwani 61621, Tanzania
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam 11102, Tanzania
- Department of Women’s and Children’s Health, International Maternal and Child Health, Uppsala University, 751 05 Uppsala, Sweden
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, 171 77 Stockholm, Sweden
- Department of Infectious Diseases, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Faith H. A. Osier
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi 80108, Kenya
- Centre of Infectious Diseases, Heidelberg University Hospital, 69120 Heidelberg, Germany
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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3
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Odera DO, Tuju J, Mwai K, Nkumama IN, Fürle K, Chege T, Kimathi R, Diehl S, Musasia FK, Rosenkranz M, Njuguna P, Hamaluba M, Kapulu MC, Frank R, Osier FHA, Abdi AI, Chi PC, de Laurent Z, Jao I, Kamuya D, Kamuyu G, Makale J, Murungi L, Musyoki J, Muthui M, Mwacharo J, Kariuki S, Mwanga D, Mwongeli J, Ndungu F, Njue M, Nyangweso G, Kimani D, Ngoi JM, Musembi J, Ngoto O, Otieno E, Ooko M, Shangala J, Wambua J, Mohammed KS, Omuoyo D, Mosobo M, Kibinge N, Kinyanjui S, Bejon P, Lowe B, Marsh K, Marsh V, Abebe Y, Billingsley PF, Sim BKL, Hoffman SL, James ER, Richie TL, Audi A, Olewe F, Oloo J, Ongecha J, Ongas MO, Koskei N, Bull PC, Hodgson SH, Kivisi C, Imwong M, Murphy SC, Ogutu B, Tarning J, Winterberg M, Williams TN. Anti-merozoite antibodies induce natural killer cell effector function and are associated with immunity against malaria. Sci Transl Med 2023; 15:eabn5993. [PMID: 36753561 DOI: 10.1126/scitranslmed.abn5993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Natural killer (NK) cells are potent immune effectors that can be activated via antibody-mediated Fc receptor engagement. Using multiparameter flow cytometry, we found that NK cells degranulate and release IFN-γ upon stimulation with antibody-opsonized Plasmodium falciparum merozoites. Antibody-dependent NK (Ab-NK) activity was largely strain transcending and enhanced invasion inhibition into erythrocytes. Ab-NK was associated with the successful control of parasitemia after experimental malaria challenge in African adults. In an independent cohort study in children, Ab-NK increased with age, was boosted by concurrent P. falciparum infections, and was associated with a lower risk of clinical episodes of malaria. Nine of the 14 vaccine candidates tested induced Ab-NK, including some less well-characterized antigens: P41, P113, MSP11, RHOPH3, and Pf_11363200. These data highlight an important role of Ab-NK activity in immunity against malaria and provide a potential mechanism for evaluating vaccine candidates.
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Affiliation(s)
- Dennis O Odera
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany.,Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - James Tuju
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kennedy Mwai
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.,Epidemiology and Biostatistics Division, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Irene N Nkumama
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Kristin Fürle
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Timothy Chege
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Rinter Kimathi
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Stefan Diehl
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Fauzia K Musasia
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Micha Rosenkranz
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Patricia Njuguna
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mainga Hamaluba
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Melissa C Kapulu
- Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Roland Frank
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Faith H A Osier
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany.,Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Life Sciences, Imperial College London, UK
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4
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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,
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5
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Musasia FK, Nkumama IN, Frank R, Kipkemboi V, Schneider M, Mwai K, Odera DO, Rosenkranz M, Fürle K, Kimani D, Tuju J, Njuguna P, Hamaluba M, Kapulu MC, Wardemann H, Osier FHA. Phagocytosis of Plasmodium falciparum ring-stage parasites predicts protection against malaria. Nat Commun 2022; 13:4098. [PMID: 35835738 PMCID: PMC9281573 DOI: 10.1038/s41467-022-31640-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/27/2022] [Indexed: 01/13/2023] Open
Abstract
Ring-infected erythrocytes are the predominant asexual stage in the peripheral circulation but are rarely investigated in the context of acquired immunity against Plasmodium falciparum malaria. Here we compare antibody-dependent phagocytosis of ring-infected parasite cultures in samples from a controlled human malaria infection (CHMI) study (NCT02739763). Protected volunteers did not develop clinical symptoms, maintained parasitaemia below a predefined threshold of 500 parasites/μl and were not treated until the end of the study. Antibody-dependent phagocytosis of both ring-infected and uninfected erythrocytes from parasite cultures was strongly correlated with protection. A surface proteomic analysis revealed the presence of merozoite proteins including erythrocyte binding antigen-175 and -140 on ring-infected and uninfected erythrocytes, providing an additional antibody-mediated protective mechanism for their activity beyond invasion-inhibition. Competition phagocytosis assays support the hypothesis that merozoite antigens are the key mediators of this functional activity. Targeting ring-stage parasites may contribute to the control of parasitaemia and prevention of clinical malaria.
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Affiliation(s)
- Fauzia K. Musasia
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Irene N. Nkumama
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany ,grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Roland Frank
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Victor Kipkemboi
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany ,grid.449481.40000 0004 0427 2011Department of Biotechnology, Hochschule Rhein-Waal, Kleve, Germany
| | - Martin Schneider
- grid.7497.d0000 0004 0492 0584Genomics and Proteomics Core Facility, German Cancer Research Center, Heidelberg, Germany
| | - Kennedy Mwai
- grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya ,grid.11951.3d0000 0004 1937 1135Epidemiology and Biostatistics Division, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Dennis O. Odera
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany ,grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Micha Rosenkranz
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Kristin Fürle
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Domitila Kimani
- grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - James Tuju
- grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Patricia Njuguna
- grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mainga Hamaluba
- grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Melissa C. Kapulu
- grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Hedda Wardemann
- grid.7497.d0000 0004 0492 0584Division of B Cell Immunology, German Cancer Research Center, Heidelberg, Germany
| | | | - Faith H. A. Osier
- grid.5253.10000 0001 0328 4908Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany ,grid.33058.3d0000 0001 0155 5938Centre for Geographic Medicine Research (Coast), Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya ,grid.7445.20000 0001 2113 8111Department of Life Sciences, Imperial College London, London, UK
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6
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Abstract
A promising vaccine fails to provide durable protection against infection and clinical malaria in infants, a key malaria vaccine target population, in a phase 2b clinical trial. The need for a highly effective vaccine against malaria remains as urgent as ever.
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Affiliation(s)
- Irene N Nkumama
- Centre of Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Heidelberg, Germany
| | - Faith H A Osier
- IAVI Human Immunology Laboratory, Imperial College London, London, UK.
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7
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Osier FHA, Murungi LM. Smashing Stereotypes: Mutual Respect, Key to Embracing Diversity. Trends Parasitol 2021; 37:265-267. [PMID: 33518435 DOI: 10.1016/j.pt.2021.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 10/22/2022]
Abstract
The path to a successful international career in science is daunting for most, and women in Africa are no exception. We are grossly under-represented as senior authors in high-impact publications and keynote speakers at international conferences, and rarely head major funding networks. Smashing long-held stereotypes may ease the journey.
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Affiliation(s)
- Faith H A Osier
- Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany; KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-, Coast, Kilifi, Kenya.
| | - Linda M Murungi
- International AIDS Vaccine Initiative (IAVI), Nairobi, Kenya
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8
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Osier FHA, Mwandumba HC, Gray CM. Turning Discoveries into Treatments: Immunology in Africa. Trends Immunol 2020; 41:1051-1053. [PMID: 33160840 DOI: 10.1016/j.it.2020.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 11/15/2022]
Abstract
An exemplar outcome of an immunology-based intervention is vaccine development; the current COVID-19 pandemic is a case in point. Can we build an immunology research ecosystem in Africa that nurtures discovery and enables translation? We see African immunologists as key agents of change and discuss obstacles and opportunities.
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Affiliation(s)
- Faith H A Osier
- Centre of Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany; KEMRI Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.
| | - Henry C Mwandumba
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
| | - Clive M Gray
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine and Department of Pathology, University of Cape Town, Cape Town, South Africa
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9
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Aniweh Y, Nyarko PB, Charles-Chess E, Ansah F, Osier FHA, Quansah E, Thiam LG, Kamuyu G, Marsh K, Conway DJ, Tetteh KKA, Awandare GA. Plasmodium falciparum Merozoite Associated Armadillo Protein (PfMAAP) Is Apically Localized in Free Merozoites and Antibodies Are Associated With Reduced Risk of Malaria. Front Immunol 2020; 11:505. [PMID: 32318061 PMCID: PMC7155890 DOI: 10.3389/fimmu.2020.00505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 03/05/2020] [Indexed: 11/19/2022] Open
Abstract
Understanding the functional role of proteins expressed by Plasmodium falciparum is an important step toward unlocking potential targets for the development of therapeutic or diagnostic interventions. The armadillo (ARM) repeat protein superfamily is associated with varied functions across the eukaryotes. Therefore, it is important to understand the role of members of this protein family in Plasmodium biology. The Plasmodium falciparum armadillo repeats only (PfARO; Pf3D7_0414900) and P. falciparum merozoite organizing proteins (PfMOP; Pf3D7_0917000) are armadillo-repeat containing proteins previously characterized in P. falciparum. Here, we describe the characterization of another ARM repeat-containing protein in P. falciparum, which we have named the P. falciparum Merozoites-Associated Armadillo repeats protein (PfMAAP). Antibodies raised to three different synthetic peptides of PfMAAP show apical staining of free merozoites and those within the mature infected schizont. We also demonstrate that the antibodies raised to the PfMAAP peptides inhibited invasion of erythrocytes by merozoites from different parasite isolates. In addition, naturally acquired human antibodies to the N- and C- termini of PfMAAP are associated with a reduced risk of malaria in a prospective cohort analysis.
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Affiliation(s)
- Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Prince B. Nyarko
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Essel Charles-Chess
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Faith H. A. Osier
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
- Department of Biochemistry, Pwani University, Kilifi, Kenya
- Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Evelyn Quansah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Laty Gaye Thiam
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Gathoni Kamuyu
- Division of Medicine, Department of Respiratory Medicine, UCL, London, United Kingdom
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
- Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - David J. Conway
- Department of Infection Biology, London School of Tropical Medicine and Hygiene, London, United Kingdom
| | - Kevin K. A. Tetteh
- Department of Infection Biology, London School of Tropical Medicine and Hygiene, London, United Kingdom
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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10
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Yman V, White MT, Asghar M, Sundling C, Sondén K, Draper SJ, Osier FHA, Färnert A. Antibody responses to merozoite antigens after natural Plasmodium falciparum infection: kinetics and longevity in absence of re-exposure. BMC Med 2019; 17:22. [PMID: 30696449 PMCID: PMC6352425 DOI: 10.1186/s12916-019-1255-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 01/08/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Antibodies against merozoite antigens are key components of malaria immunity. The naturally acquired antibody response to these antigens is generally considered short-lived; however, the underlying mechanisms remain unclear. Prospective studies of travellers with different levels of prior exposure, returning to malaria-free countries with Plasmodium infection, offer a unique opportunity to investigate the kinetics and composition of the antibody response after natural infection. METHODS Adults diagnosed with P. falciparum malaria in Stockholm, Sweden (20 likely malaria naïve and 41 with repeated previous exposure during residency in sub-Saharan Africa) were sampled at diagnosis and 10 days and 1, 3, 6, and 12 months after treatment. Total and subclass-specific IgG responses to P. falciparum merozoite antigens (AMA-1, MSP-119, MSP-2, MSP-3, and RH5) and tetanus toxoid were measured by multiplex bead-based immunoassays and ELISA. Mathematical modelling was used to estimate the exposure-dependent longevity of antibodies and antibody-secreting cells (ASCs). RESULTS A majority of individuals mounted detectable antibody responses towards P. falciparum merozoite antigens at diagnosis; however, the magnitude and breadth were greater in individuals with prior exposure. In both exposure groups, antibody levels increased rapidly for 2 weeks and decayed thereafter. Previously exposed individuals maintained two- to ninefold greater antibody levels throughout the 1-year follow-up. The half-lives of malaria-specific long-lived ASCs, responsible for maintaining circulating antibodies, ranged from 1.8 to 3.7 years for merozoite antigens and were considerably short compared to tetanus-specific ASCs. Primary infected individuals did acquire a long-lived component of the antibody response; however, the total proportion of long-lived ASCs generated in response to infection was estimated not to exceed 10%. In contrast, previously exposed individuals maintained substantially larger numbers of long-lived ASCs (10-56% of total ASCs). CONCLUSION The short-lived nature of the naturally acquired antibody response, to all tested merozoite antigens, following primary malaria infection can be attributed to a combination of a poor acquisition and short half-life of long-lived ASCs. Greater longevity is acquired with repeated infections and can be explained by the maintenance of larger numbers of long-lived ASCs. These insights advance our understanding of naturally acquired malaria immunity and will guide strategies for further development of both vaccines and serological tools to monitor exposure.
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Affiliation(s)
- Victor Yman
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden.
| | - Michael T White
- Department of Parasites and Insect Vectors, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France
| | - Muhammad Asghar
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Christopher Sundling
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Klara Sondén
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
- Department of Infectious Diseases, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Simon J Draper
- Jenner Institute, University of Oxford, Oxford, OX3 7DQ, UK
| | - Faith H A Osier
- Kenya Medical Research Institute - Wellcome Trust Research Program, Centre for Geographic Medicine Research-Coast, PO Box 230-80108, Kilifi, Kenya
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, 171 76, Stockholm, Sweden
- Department of Infectious Diseases, Karolinska University Hospital, 171 76, Stockholm, Sweden
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11
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Kamuyu G, Tuju J, Kimathi R, Mwai K, Mburu J, Kibinge N, Chong Kwan M, Hawkings S, Yaa R, Chepsat E, Njunge JM, Chege T, Guleid F, Rosenkranz M, Kariuki CK, Frank R, Kinyanjui SM, Murungi LM, Bejon P, Färnert A, Tetteh KKA, Beeson JG, Conway DJ, Marsh K, Rayner JC, Osier FHA. KILchip v1.0: A Novel Plasmodium falciparum Merozoite Protein Microarray to Facilitate Malaria Vaccine Candidate Prioritization. Front Immunol 2018; 9:2866. [PMID: 30619257 PMCID: PMC6298441 DOI: 10.3389/fimmu.2018.02866] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/21/2018] [Indexed: 12/12/2022] Open
Abstract
Passive transfer studies in humans clearly demonstrated the protective role of IgG antibodies against malaria. Identifying the precise parasite antigens that mediate immunity is essential for vaccine design, but has proved difficult. Completion of the Plasmodium falciparum genome revealed thousands of potential vaccine candidates, but a significant bottleneck remains in their validation and prioritization for further evaluation in clinical trials. Focusing initially on the Plasmodium falciparum merozoite proteome, we used peer-reviewed publications, multiple proteomic and bioinformatic approaches, to select and prioritize potential immune targets. We expressed 109 P. falciparum recombinant proteins, the majority of which were obtained using a mammalian expression system that has been shown to produce biologically functional extracellular proteins, and used them to create KILchip v1.0: a novel protein microarray to facilitate high-throughput multiplexed antibody detection from individual samples. The microarray assay was highly specific; antibodies against P. falciparum proteins were detected exclusively in sera from malaria-exposed but not malaria-naïve individuals. The intensity of antibody reactivity varied as expected from strong to weak across well-studied antigens such as AMA1 and RH5 (Kruskal–Wallis H test for trend: p < 0.0001). The inter-assay and intra-assay variability was minimal, with reproducible results obtained in re-assays using the same chip over a duration of 3 months. Antibodies quantified using the multiplexed format in KILchip v1.0 were highly correlated with those measured in the gold-standard monoplex ELISA [median (range) Spearman's R of 0.84 (0.65–0.95)]. KILchip v1.0 is a robust, scalable and adaptable protein microarray that has broad applicability to studies of naturally acquired immunity against malaria by providing a standardized tool for the detection of antibody correlates of protection. It will facilitate rapid high-throughput validation and prioritization of potential Plasmodium falciparum merozoite-stage antigens paving the way for urgently needed clinical trials for the next generation of malaria vaccines.
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Affiliation(s)
- Gathoni Kamuyu
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - James Tuju
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Department of Biochemistry, Pwani University, Kilifi, Kenya
| | - Rinter Kimathi
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Kennedy Mwai
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - James Mburu
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Nelson Kibinge
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Marisa Chong Kwan
- Arrayjet, Innovative Microarray Solutions, Edinburgh, United Kingdom
| | - Sam Hawkings
- Arrayjet, Innovative Microarray Solutions, Edinburgh, United Kingdom
| | - Reuben Yaa
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Emily Chepsat
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - James M Njunge
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Timothy Chege
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Fatuma Guleid
- Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Micha Rosenkranz
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Christopher K Kariuki
- Department of Tropical and Infectious Diseases, Institute of Primate Research, Nairobi, Kenya.,Cellular and Molecular Immunology, Vrije Universiteit Brussels, Brussels, Belgium
| | - Roland Frank
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Samson M Kinyanjui
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Department of Biochemistry, Pwani University, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Linda M Murungi
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Kevin K A Tetteh
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia.,Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - David J Conway
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.,African Academy of Sciences, Nairobi, Kenya
| | - Julian C Rayner
- Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Faith H A Osier
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.,Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany.,Department of Biochemistry, Pwani University, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
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12
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Tuju J, Kamuyu G, Murungi LM, Osier FHA. Vaccine candidate discovery for the next generation of malaria vaccines. Immunology 2017; 152:195-206. [PMID: 28646586 PMCID: PMC5588761 DOI: 10.1111/imm.12780] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/12/2017] [Accepted: 06/19/2017] [Indexed: 12/21/2022] Open
Abstract
Although epidemiological observations, IgG passive transfer studies and experimental infections in humans all support the feasibility of developing highly effective malaria vaccines, the precise antigens that induce protective immunity remain uncertain. Here, we review the methodologies applied to vaccine candidate discovery for Plasmodium falciparum malaria from the pre- to post-genomic era. Probing of genomic and cDNA libraries with antibodies of defined specificities or functional activity predominated the former, whereas reverse vaccinology encompassing high throughput in silico analyses of genomic, transcriptomic or proteomic parasite data sets is the mainstay of the latter. Antibody-guided vaccine design spanned both eras but currently benefits from technological advances facilitating high-throughput screening and downstream applications. We make the case that although we have exponentially increased our ability to identify numerous potential vaccine candidates in a relatively short space of time, a significant bottleneck remains in their validation and prioritization for evaluation in clinical trials. Longitudinal cohort studies provide supportive evidence but results are often conflicting between studies. Demonstration of antigen-specific antibody function is valuable but the relative importance of one mechanism over another with regards to protection remains undetermined. Animal models offer useful insights but may not accurately reflect human disease. Challenge studies in humans are preferable but prohibitively expensive. In the absence of reliable correlates of protection, suitable animal models or a better understanding of the mechanisms underlying protective immunity in humans, vaccine candidate discovery per se may not be sufficient to provide the paradigm shift necessary to develop the next generation of highly effective subunit malaria vaccines.
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Affiliation(s)
- James Tuju
- KEMRI‐Wellcome Trust Research ProgrammeCentre for Geographic Medicine CoastKilifiKenya
- Department of BiochemistryPwani UniversityKilifiKenya
| | - Gathoni Kamuyu
- KEMRI‐Wellcome Trust Research ProgrammeCentre for Geographic Medicine CoastKilifiKenya
| | - Linda M. Murungi
- KEMRI‐Wellcome Trust Research ProgrammeCentre for Geographic Medicine CoastKilifiKenya
| | - Faith H. A. Osier
- KEMRI‐Wellcome Trust Research ProgrammeCentre for Geographic Medicine CoastKilifiKenya
- Centre for Infectious DiseasesHeidelberg University HospitalHeidelbergGermany
- Department of Biomedical SciencesPwani UniversityKilifiKenya
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13
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Nkumama IN, O'Meara WP, Osier FHA. Changes in Malaria Epidemiology in Africa and New Challenges for Elimination. Trends Parasitol 2017; 33:128-140. [PMID: 27939610 PMCID: PMC6995363 DOI: 10.1016/j.pt.2016.11.006] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/28/2016] [Accepted: 11/11/2016] [Indexed: 12/20/2022]
Abstract
Although the burden of Plasmodium falciparum malaria is gradually declining in many parts of Africa, it is characterized by spatial and temporal variability that presents new and evolving challenges for malaria control programs. Reductions in the malaria burden need to be sustained in the face of changing epidemiology whilst simultaneously tackling significant pockets of sustained or increasing transmission. Large-scale, robust surveillance mechanisms that measure rather than estimate the actual burden of malaria over time from large areas of the continent where such data are lacking need to be prioritized. We review these fascinating developments, caution against complacency, and make the case that improving the extent and quality of malaria surveillance is vital for Africa as she marches on towards elimination.
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Affiliation(s)
- Irene N Nkumama
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230-80108, Kilifi, Kenya
| | - Wendy P O'Meara
- Duke University, Durham, NC, USA; Moi University College of Health Sciences, Eldoret, Kenya
| | - Faith H A Osier
- KEMRI-Wellcome Trust Research Programme, P.O. Box 230-80108, Kilifi, Kenya.
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14
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Murungi LM, Sondén K, Odera D, Oduor LB, Guleid F, Nkumama IN, Otiende M, Kangoye DT, Fegan G, Färnert A, Marsh K, Osier FHA. Cord blood IgG and the risk of severe Plasmodium falciparum malaria in the first year of life. Int J Parasitol 2016; 47:153-162. [PMID: 27890694 PMCID: PMC5297353 DOI: 10.1016/j.ijpara.2016.09.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 08/31/2016] [Accepted: 09/03/2016] [Indexed: 01/18/2023]
Abstract
Severe malaria episodes are rare during the first few months of life. The rate of decay of cord blood IgG is inversely proportional to the starting concentration. Antibody dependent respiratory burst mediated by cord IgG protects from severe malaria during the first 6 months of infancy.
Young infants are less susceptible to severe episodes of malaria but the targets and mechanisms of protection are not clear. Cord blood antibodies may play an important role in mediating protection but many studies have examined their association with the outcome of infection or non-severe malaria. Here, we investigated whether cord blood IgG to Plasmodium falciparum merozoite antigens and antibody-mediated effector functions were associated with reduced odds of developing severe malaria at different time points during the first year of life. We conducted a case-control study of well-defined severe falciparum malaria nested within a longitudinal birth cohort of Kenyan children. We measured cord blood total IgG levels against five recombinant merozoite antigens and antibody function in the growth inhibition activity and neutrophil antibody-dependent respiratory burst assays. We also assessed the decay of maternal antibodies during the first 6 months of life. The mean antibody half-life range was 2.51 months (95% confidence interval (CI): 2.19–2.92) to 4.91 months (95% CI: 4.47–6.07). The rate of decline of maternal antibodies was inversely proportional to the starting concentration. The functional assay of antibody-dependent respiratory burst activity predicted significantly reduced odds of developing severe malaria during the first 6 months of life (Odds ratio (OR) 0.07, 95% CI: 0.007–0.74, P = 0.007). Identification of the targets of antibodies mediating antibody-dependent respiratory burst activity could contribute to the development of malaria vaccines that protect against severe episodes of malaria in early infancy.
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Affiliation(s)
- Linda M Murungi
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya.
| | - Klara Sondén
- Unit of Infectious Diseases, Department of Medicine, Solna, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Dennis Odera
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Loureen B Oduor
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Fatuma Guleid
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Irene N Nkumama
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Mark Otiende
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - David T Kangoye
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya; Centre National de Recherche et de Formation sur le Paludisme (CNRFP), 01 BP 2208, Ouagadougou 01, Burkina Faso
| | - Greg Fegan
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
| | - Anna Färnert
- Unit of Infectious Diseases, Department of Medicine, Solna, Karolinska Institutet, SE-171 76 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Kevin Marsh
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya; African Academy of Sciences, P.O. Box 24916-00502, Nairobi, Kenya; Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Faith H A Osier
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya
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15
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Affiliation(s)
- F H A Osier
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Coast, Kilifi District Hospital, Paediatric Department, Kilifi.
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16
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Murungi LM, Sondén K, Llewellyn D, Rono J, Guleid F, Williams AR, Ogada E, Thairu A, Färnert A, Marsh K, Draper SJ, Osier FHA. Targets and Mechanisms Associated with Protection from Severe Plasmodium falciparum Malaria in Kenyan Children. Infect Immun 2016; 84:950-963. [PMID: 26787721 PMCID: PMC4807498 DOI: 10.1128/iai.01120-15] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/14/2016] [Indexed: 01/23/2023] Open
Abstract
Severe malaria (SM) is a life-threatening complication of infection with Plasmodium falciparum Epidemiological observations have long indicated that immunity against SM is acquired relatively rapidly, but prospective studies to investigate its immunological basis are logistically challenging and have rarely been undertaken. We investigated the merozoite targets and antibody-mediated mechanisms associated with protection against SM in Kenyan children aged 0 to 2 years. We designed a unique prospective matched case-control study of well-characterized SM clinical phenotypes nested within a longitudinal birth cohort of children (n= 5,949) monitored over the first 2 years of life. We quantified immunological parameters in sera collected before the SM event in cases and their individually matched controls to evaluate the prospective odds of developing SM in the first 2 years of life. Anti-AMA1 antibodies were associated with a significant reduction in the odds of developing SM (odds ratio [OR] = 0.37; 95% confidence interval [CI] = 0.15 to 0.90; P= 0.029) after adjustment for responses to all other merozoite antigens tested, while those against MSP-2, MSP-3, Plasmodium falciparum Rh2 [PfRh2], MSP-119, and the infected red blood cell surface antigens were not. The combined ability of total IgG to inhibit parasite growth and mediate the release of reactive oxygen species from neutrophils was associated with a marked reduction in the odds of developing SM (OR = 0.07; 95% CI = 0.006 to 0.82;P= 0.03). Assays of these two functional mechanisms were poorly correlated (Spearman rank correlation coefficient [rs] = 0.12;P= 0.07). Our data provide epidemiological evidence that multiple antibody-dependent mechanisms contribute to protective immunity via distinct targets whose identification could accelerate the development of vaccines to protect against SM.
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Affiliation(s)
- Linda M Murungi
- KEMRI Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
| | - Klara Sondén
- Unit of Infectious Diseases, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
| | - David Llewellyn
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Josea Rono
- KEMRI Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
| | - Fatuma Guleid
- KEMRI Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
| | | | - Edna Ogada
- KEMRI Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
| | - Amos Thairu
- KEMRI Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
| | - Anna Färnert
- Unit of Infectious Diseases, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
| | - Kevin Marsh
- KEMRI Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
- Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Simon J Draper
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Faith H A Osier
- KEMRI Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
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17
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Terheggen U, Drew DR, Hodder AN, Cross NJ, Mugyenyi CK, Barry AE, Anders RF, Dutta S, Osier FHA, Elliott SR, Senn N, Stanisic DI, Marsh K, Siba PM, Mueller I, Richards JS, Beeson JG. Limited antigenic diversity of Plasmodium falciparum apical membrane antigen 1 supports the development of effective multi-allele vaccines. BMC Med 2014; 12:183. [PMID: 25319190 PMCID: PMC4212128 DOI: 10.1186/s12916-014-0183-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 09/10/2014] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Polymorphism in antigens is a common mechanism for immune evasion used by many important pathogens, and presents major challenges in vaccine development. In malaria, many key immune targets and vaccine candidates show substantial polymorphism. However, knowledge on antigenic diversity of key antigens, the impact of polymorphism on potential vaccine escape, and how sequence polymorphism relates to antigenic differences is very limited, yet crucial for vaccine development. Plasmodium falciparum apical membrane antigen 1 (AMA1) is an important target of naturally-acquired antibodies in malaria immunity and a leading vaccine candidate. However, AMA1 has extensive allelic diversity with more than 60 polymorphic amino acid residues and more than 200 haplotypes in a single population. Therefore, AMA1 serves as an excellent model to assess antigenic diversity in malaria vaccine antigens and the feasibility of multi-allele vaccine approaches. While most previous research has focused on sequence diversity and antibody responses in laboratory animals, little has been done on the cross-reactivity of human antibodies. METHODS We aimed to determine the extent of antigenic diversity of AMA1, defined by reactivity with human antibodies, and to aid the identification of specific alleles for potential inclusion in a multi-allele vaccine. We developed an approach using a multiple-antigen-competition enzyme-linked immunosorbent assay (ELISA) to examine cross-reactivity of naturally-acquired antibodies in Papua New Guinea and Kenya, and related this to differences in AMA1 sequence. RESULTS We found that adults had greater cross-reactivity of antibodies than children, although the patterns of cross-reactivity to alleles were the same. Patterns of antibody cross-reactivity were very similar between populations (Papua New Guinea and Kenya), and over time. Further, our results show that antigenic diversity of AMA1 alleles is surprisingly restricted, despite extensive sequence polymorphism. Our findings suggest that a combination of three different alleles, if selected appropriately, may be sufficient to cover the majority of antigenic diversity in polymorphic AMA1 antigens. Antigenic properties were not strongly related to existing haplotype groupings based on sequence analysis. CONCLUSIONS Antigenic diversity of AMA1 is limited and a vaccine including a small number of alleles might be sufficient for coverage against naturally-circulating strains, supporting a multi-allele approach for developing polymorphic antigens as malaria vaccines.
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Affiliation(s)
- Ulrich Terheggen
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia.
| | - Damien R Drew
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.
| | | | - Nadia J Cross
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.
| | - Cleopatra K Mugyenyi
- Centre for Geographic Medicine, Coast, Kenya Medical Research Institute, Kilifi, Kenya.
| | - Alyssa E Barry
- Walter and Eliza Hall Institute, Melbourne, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia.
| | | | | | - Faith H A Osier
- Centre for Geographic Medicine, Coast, Kenya Medical Research Institute, Kilifi, Kenya.
| | - Salenna R Elliott
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.
| | - Nicolas Senn
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Danielle I Stanisic
- Walter and Eliza Hall Institute, Melbourne, Australia. .,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Kevin Marsh
- Centre for Geographic Medicine, Coast, Kenya Medical Research Institute, Kilifi, Kenya.
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Ivo Mueller
- Walter and Eliza Hall Institute, Melbourne, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia. .,Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Jack S Richards
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, Australia.
| | - James G Beeson
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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Kamuyu G, Bottomley C, Mageto J, Lowe B, Wilkins PP, Noh JC, Nutman TB, Ngugi AK, Odhiambo R, Wagner RG, Kakooza-Mwesige A, Owusu-Agyei S, Ae-Ngibise K, Masanja H, Osier FHA, Odermatt P, Newton CR. Exposure to multiple parasites is associated with the prevalence of active convulsive epilepsy in sub-Saharan Africa. PLoS Negl Trop Dis 2014; 8:e2908. [PMID: 24875312 PMCID: PMC4038481 DOI: 10.1371/journal.pntd.0002908] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 04/16/2014] [Indexed: 11/21/2022] Open
Abstract
Background Epilepsy is common in developing countries, and it is often associated with parasitic infections. We investigated the relationship between exposure to parasitic infections, particularly multiple infections and active convulsive epilepsy (ACE), in five sites across sub-Saharan Africa. Methods and Findings A case-control design that matched on age and location was used. Blood samples were collected from 986 prevalent cases and 1,313 age-matched community controls and tested for presence of antibodies to Onchocerca volvulus, Toxocara canis, Toxoplasma gondii, Plasmodium falciparum, Taenia solium and HIV. Exposure (seropositivity) to Onchocerca volvulus (OR = 1.98; 95%CI: 1.52–2.58, p<0.001), Toxocara canis (OR = 1.52; 95%CI: 1.23–1.87, p<0.001), Toxoplasma gondii (OR = 1.28; 95%CI: 1.04–1.56, p = 0.018) and higher antibody levels (top tertile) to Toxocara canis (OR = 1.70; 95%CI: 1.30–2.24, p<0.001) were associated with an increased prevalence of ACE. Exposure to multiple infections was common (73.8% of cases and 65.5% of controls had been exposed to two or more infections), and for T. gondii and O. volvulus co-infection, their combined effect on the prevalence of ACE, as determined by the relative excess risk due to interaction (RERI), was more than additive (T. gondii and O. volvulus, RERI = 1.19). The prevalence of T. solium antibodies was low (2.8% of cases and 2.2% of controls) and was not associated with ACE in the study areas. Conclusion This study investigates how the degree of exposure to parasites and multiple parasitic infections are associated with ACE and may explain conflicting results obtained when only seropositivity is considered. The findings from this study should be further validated. The prevalence of epilepsy is greater in developing countries compared to developed countries, and parasitic infestations are thought to contribute to this increased burden. We conducted a case-control study across five sites in sub-Saharan Africa to investigate the relationship between epilepsy and exposure to parasitic infections, and the association between epilepsy and multiple co-incidental infections. Exposure to Onchocerca volvulus, Toxocara canis and Toxoplasma gondii as well as high antibody levels (top tertile) to Toxocara canis was positively associated with the prevalence of active convulsive epilepsy (ACE). Multiple co-incidental parasitic infections were common, and the combined effect of T. gondii and O. volvulus co-infection on ACE was greater than the sum of the individual effects. The contribution of each of these parasitic infections on the burden of epilepsy in sub-Saharan Africa should be explored.
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Affiliation(s)
- Gathoni Kamuyu
- KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research – Coast, Kilifi, Kenya
- Studies of the Epidemiology of Epilepsy in Demographic Surveillance Systems (SEEDS)-INDEPTH Network, Accra, Ghana
- * E-mail:
| | - Christian Bottomley
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- MRC Tropical Epidemiology Group, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - James Mageto
- KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research – Coast, Kilifi, Kenya
- Egerton University, Nakuru, Kenya
| | - Brett Lowe
- KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research – Coast, Kilifi, Kenya
- Studies of the Epidemiology of Epilepsy in Demographic Surveillance Systems (SEEDS)-INDEPTH Network, Accra, Ghana
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Patricia P. Wilkins
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
| | - John C. Noh
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, United States of America
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases. National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Anthony K. Ngugi
- KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research – Coast, Kilifi, Kenya
- Studies of the Epidemiology of Epilepsy in Demographic Surveillance Systems (SEEDS)-INDEPTH Network, Accra, Ghana
- Research Support Unit, Faculty of Health Sciences, Aga Khan University (East Africa), Nairobi, Kenya
| | - Rachael Odhiambo
- KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research – Coast, Kilifi, Kenya
| | - Ryan G. Wagner
- MRC/Wits Rural Public Health & Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Epidemiology and Public Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Angelina Kakooza-Mwesige
- Studies of the Epidemiology of Epilepsy in Demographic Surveillance Systems (SEEDS)-INDEPTH Network, Accra, Ghana
- Iganga-Mayuge Health and Demographic Surveillance System, Iganga, Uganda
- Department of Paediatrics and Child Health, Makerere University College of Health Sciences, Kampala, Uganda
| | | | | | | | - Faith H. A. Osier
- KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research – Coast, Kilifi, Kenya
| | - Peter Odermatt
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Unversity of Basel, Basel, Switzerland
| | - Charles R. Newton
- KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research – Coast, Kilifi, Kenya
- Studies of the Epidemiology of Epilepsy in Demographic Surveillance Systems (SEEDS)-INDEPTH Network, Accra, Ghana
- Neurosciences Unit, UCL Institute of Child Health, London, United Kingdom
- Clinical Research Unit, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
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Rono J, Osier FHA, Olsson D, Montgomery S, Mhoja L, Rooth I, Marsh K, Färnert A. Breadth of anti-merozoite antibody responses is associated with the genetic diversity of asymptomatic Plasmodium falciparum infections and protection against clinical malaria. Clin Infect Dis 2013; 57:1409-16. [PMID: 23983244 DOI: 10.1093/cid/cit556] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Elucidating the mechanisms of naturally acquired immunity to Plasmodium falciparum infections would be highly valuable for malaria vaccine development. Asymptomatic multiclonal infections have been shown to predict protection from clinical malaria in a transmission-dependent manner, but the mechanisms underlying this are unclear. We assessed the breadth of antibody responses to several vaccine candidate merozoite antigens in relation to the infecting parasite population and clinical immunity. METHODS In a cohort study in Tanzania, 320 children aged 1-16 years who were asymptomatic at baseline were included. We genotyped P. falciparum infections by targeting the msp2 gene using polymerase chain reaction and capillary electrophoresis and measured antibodies to 7 merozoite antigens using a multiplex assay. We assessed the correlation between the number of clones and the breadth of the antibody response, and examined their effects on the risk of malaria during 40 weeks of follow-up using age-adjusted multivariate regression models. RESULTS The antibody breadth was positively correlated with the number of clones (RR [risk ratio], 1.63; 95% confidence interval [CI], 1.32-2.02). Multiclonal infections were associated with a nonsignificant reduction in the risk of malaria in the absence of antibodies (RR, 0.83; 95% CI, .29-2.34). The breadth of the antibody response was significantly associated with a reduced risk of malaria in the absence of infections (RR, 0.25; 95% CI, .09-.66). In combination, these factors were associated with a lower risk of malaria than they were individually (RR, 0.14; 95% CI, .04-.48). CONCLUSIONS These data suggest that malaria vaccines mimicking naturally acquired immunity should ideally induce antibody responses that can be boosted by natural infections.
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Affiliation(s)
- Josea Rono
- Infectious Diseases Unit, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
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20
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Murungi LM, Kamuyu G, Lowe B, Bejon P, Theisen M, Kinyanjui SM, Marsh K, Osier FHA. A threshold concentration of anti-merozoite antibodies is required for protection from clinical episodes of malaria. Vaccine 2013; 31:3936-42. [PMID: 23800539 PMCID: PMC3763364 DOI: 10.1016/j.vaccine.2013.06.042] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 05/14/2013] [Accepted: 06/12/2013] [Indexed: 11/03/2022]
Abstract
Antibodies to selected Plasmodium falciparum merozoite antigens are often reported to be associated with protection from malaria in one epidemiological cohort, but not in another. Here, we sought to understand this paradox by exploring the hypothesis that a threshold concentration of antibodies is necessary for protection. We analyzed data from two independent cohorts along the Kenyan coast, one in which antibodies to AMA1, MSP-2 and MSP-3 were associated with protection from malaria (Chonyi) and another in which this association was not observed (Junju). We used a malaria reference reagent to standardize antibody measurements across both cohorts, and applied statistical methods to derive the threshold concentration of antibodies against each antigen that best correlated with a reduced risk of malaria (the protective threshold), in the Chonyi cohort. We then tested whether antibodies in Junju reached the protective threshold concentrations observed in the Chonyi cohort. Except for children under 3 years, the age-matched proportions of children achieving protective threshold concentrations of antibodies against AMA1 and MSP-2 were significantly lower in Junju compared to Chonyi (Fishers exact test, P<0.01). For MSP-3, this difference was significant only among 4-5 year olds. We conclude that although antibodies are commonly detected in malaria endemic populations, they may be present in concentrations that are insufficient for protection. Our results have implications for the analysis and interpretation of similar data from immuno-epidemiological studies.
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Affiliation(s)
- Linda M Murungi
- KEMRI Centre for Geographic Medicine Research, Coast, P.O. Box 230-80108, Kilifi, Kenya.
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21
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Osier FHA, Murungi LM, Fegan G, Tuju J, Tetteh KK, Bull PC, Conway DJ, Marsh K. Allele-specific antibodies to Plasmodium falciparum merozoite surface protein-2 and protection against clinical malaria. Parasite Immunol 2010; 32:193-201. [PMID: 20398182 PMCID: PMC2847195 DOI: 10.1111/j.1365-3024.2009.01178.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
IgG and IgG3 antibodies to merozoite surface protein-2 (MSP-2) of Plasmodium falciparum have been associated with protection from clinical malaria in independent studies. We determined whether this protection was allele-specific by testing whether children who developed clinical malaria lacked IgG/IgG3 antibodies specific to the dominant msp2 parasite genotypes detected during clinical episodes. We analysed pre-existing IgG and IgG1/IgG3 antibodies to antigens representing the major dimorphic types of MSP-2 by ELISA. We used quantitative real-time PCR to determine the dominant msp2 alleles in parasites detected in clinical episodes. Over half (55%, 80/146) of infections contained both allelic types. Single or dominant IC1- and FC27-like alleles were detected in 46% and 42% of infections respectively, and both types were equally dominant in 12%. High levels of IgG/IgG3 antibodies to the FC27-like antigen were not significantly associated with a lower likelihood of clinical episodes caused by parasites bearing FC27-like compared to IC1-like alleles, and vice versa for IgG/IgG3 antibodies to the IC1-like antigen. These findings were supported by competition ELISAs which demonstrated the presence of IgG antibodies to allele-specific epitopes within both antigens. Thus, even for this well-studied antigen, the importance of an allele-specific component of naturally acquired protective immunity to malaria remains to be confirmed.
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Affiliation(s)
- F H A Osier
- KEMRI-Centre for Geographic Medicine Research, Coast, Kilifi, Kenya.
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22
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Bejon P, Williams TN, Liljander A, Noor AM, Wambua J, Ogada E, Olotu A, Osier FHA, Hay SI, Färnert A, Marsh K. Stable and unstable malaria hotspots in longitudinal cohort studies in Kenya. PLoS Med 2010; 7:e1000304. [PMID: 20625549 PMCID: PMC2897769 DOI: 10.1371/journal.pmed.1000304] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/27/2010] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Infectious diseases often demonstrate heterogeneity of transmission among host populations. This heterogeneity reduces the efficacy of control strategies, but also implies that focusing control strategies on "hotspots" of transmission could be highly effective. METHODS AND FINDINGS In order to identify hotspots of malaria transmission, we analysed longitudinal data on febrile malaria episodes, asymptomatic parasitaemia, and antibody titres over 12 y from 256 homesteads in three study areas in Kilifi District on the Kenyan coast. We examined heterogeneity by homestead, and identified groups of homesteads that formed hotspots using a spatial scan statistic. Two types of statistically significant hotspots were detected; stable hotspots of asymptomatic parasitaemia and unstable hotspots of febrile malaria. The stable hotspots were associated with higher average AMA-1 antibody titres than the unstable clusters (optical density [OD] = 1.24, 95% confidence interval [CI] 1.02-1.47 versus OD = 1.1, 95% CI 0.88-1.33) and lower mean ages of febrile malaria episodes (5.8 y, 95% CI 5.6-6.0 versus 5.91 y, 95% CI 5.7-6.1). A falling gradient of febrile malaria incidence was identified in the penumbrae of both hotspots. Hotspots were associated with AMA-1 titres, but not seroconversion rates. In order to target control measures, homesteads at risk of febrile malaria could be predicted by identifying the 20% of homesteads that experienced an episode of febrile malaria during one month in the dry season. That 20% subsequently experienced 65% of all febrile malaria episodes during the following year. A definition based on remote sensing data was 81% sensitive and 63% specific for the stable hotspots of asymptomatic malaria. CONCLUSIONS Hotspots of asymptomatic parasitaemia are stable over time, but hotspots of febrile malaria are unstable. This finding may be because immunity offsets the high rate of febrile malaria that might otherwise result in stable hotspots, whereas unstable hotspots necessarily affect a population with less prior exposure to malaria.
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Affiliation(s)
- Philip Bejon
- Kilifi KEMRI-Wellcome Trust Collaborative Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya.
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Verra F, Simpore J, Warimwe GM, Tetteh KK, Howard T, Osier FHA, Bancone G, Avellino P, Blot I, Fegan G, Bull PC, Williams TN, Conway DJ, Marsh K, Modiano D. Haemoglobin C and S role in acquired immunity against Plasmodium falciparum malaria. PLoS One 2007; 2:e978. [PMID: 17912355 PMCID: PMC1991593 DOI: 10.1371/journal.pone.0000978] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Accepted: 09/13/2007] [Indexed: 11/19/2022] Open
Abstract
A recently proposed mechanism of protection for haemoglobin C (HbC; β6Glu→Lys) links an abnormal display of PfEMP1, an antigen involved in malaria pathogenesis, on the surface of HbC infected erythrocytes together with the observation of reduced cytoadhesion of parasitized erythrocytes and impaired rosetting in vitro. We investigated the impact of this hypothesis on the development of acquired immunity against Plasmodium falciparum variant surface antigens (VSA) encoding PfEMP1 in HbC in comparison with HbA and HbS carriers of Burkina Faso. We measured: i) total IgG against a single VSA, A4U, and against a panel of VSA from severe malaria cases in human sera from urban and rural areas of Burkina Faso of different haemoglobin genotypes (CC, AC, AS, SC, SS); ii) total IgG against recombinant proteins of P. falciparum asexual sporozoite, blood stage antigens, and parasite schizont extract; iii) total IgG against tetanus toxoid. Results showed that the reported abnormal cell-surface display of PfEMP1 on HbC infected erythrocytes observed in vitro is not associated to lower anti- PfEMP1 response in vivo. Higher immune response against the VSA panel and malaria antigens were observed in all adaptive genotypes containing at least one allelic variant HbC or HbS in the low transmission urban area whereas no differences were detected in the high transmission rural area. In both contexts the response against tetanus toxoid was not influenced by the β-globin genotype. These findings suggest that both HbC and HbS affect the early development of naturally acquired immunity against malaria. The enhanced immune reactivity in both HbC and HbS carriers supports the hypothesis that the protection against malaria of these adaptive genotypes might be at least partially mediated by acquired immunity against malaria.
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Affiliation(s)
- Federica Verra
- Dipartimento di Scienze di Sanità Pubblica, Sezione di Parassitologia, University of Rome-La Sapienza, Rome, Italy.
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Osier FHA, Polley SD, Mwangi T, Lowe B, Conway DJ, Marsh K. Naturally acquired antibodies to polymorphic and conserved epitopes of Plasmodium falciparum merozoite surface protein 3. Parasite Immunol 2007; 29:387-94. [PMID: 17650180 PMCID: PMC1976398 DOI: 10.1111/j.1365-3024.2007.00951.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many studies on the role of merozoite surface protein 3 (MSP3) in immunity against malaria have focused on a conserved section of MSP3. New evidence suggests that polymorphic sequences within MSP3 are under immune selection. We report a detailed analysis of naturally-acquired antibodies to allele-specific and conserved parts of MSP3 in a Kenyan cohort. Indirect and competition ELISA to heterologous recombinant MSP3 proteins were used for antibody assays, and parasites were genotyped for msp3 alleles. Antibody reactivity to allele-specific and conserved epitopes of MSP3 was heterogenous between individuals. Overall, the prevalence of allele-specific antibody reactivity was significantly higher (3D7-specific 54%, K1-specific 41%) than that to a recombinant protein representing a conserved portion of C-terminal MSP3 (24%, P < 0·01). The most abundant IgG subclass was IgG3, followed by IgG1. Allele-specific reactivity to the K1-type of MSP3 was associated with a lower risk of clinical malaria episodes during a 6-month follow-up in individuals who were parasitized at the start of the malaria transmission season (Relative risk 0·41 with 95% confidence interval 0·20–0·81, P = 0·011). The potential importance of allele-specific immunity to MSP3 should be considered in addition to immunity to conserved epitopes, in the development of an MSP3 malaria vaccine.
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Affiliation(s)
- F H A Osier
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.
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Osier FHA, Berkley JA, Ross A, Sanderson F, Mohammed S, Newton CRJC. Abnormal blood glucose concentrations on admission to a rural Kenyan district hospital: prevalence and outcome. Arch Dis Child 2003; 88:621-5. [PMID: 12818911 PMCID: PMC1763181 DOI: 10.1136/adc.88.7.621] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS To determine the prevalence, clinical characteristics, and outcome of hypoglycaemia on admission in children at a rural Kenyan district hospital. METHODS Observational study of 3742 children (including 280 neonates) in Kilifi District Hospital, Kenya. MAIN OUTCOME MEASURES hypoglycaemia (blood glucose <2.2 mmol/l) and hyperglycaemia (blood glucose >10.0 mmol/l). RESULTS Non-neonates: the prevalence of hypoglycaemia on admission was 7.3%. Severe illness, malnutrition, last meal >12 hours ago, and a positive malaria slide were independently associated with hypoglycaemia. Overall, mortality in hypoglycaemic children was 20.2% compared to 3.8% in normoglycaemic children (p < 0.001). The brunt of mortality in hypoglycaemic children was borne by those who were severely ill or malnourished (31.8%) as opposed to those who were neither severely ill nor malnourished (9.0%). Neonates: 23.0% of neonates were hypoglycaemic on admission. Inability to breast feed and weight <2500 g were independently associated with hypoglycaemia. Mortality was 45.2% compared to 19.6% in normoglycaemic neonates (p < 0.001). Hyperglycaemia was present in 2.7% of children and was associated with a higher mortality than normoglycaemia, 14.0% versus 3.8% respectively (p < 0.001). CONCLUSIONS Hypoglycaemia is common in children admitted to a rural Kenyan district hospital and is associated with an increased mortality. Apart from features of severe illness and poor feeding, clinical signs have a low sensitivity and specificity for hypoglycaemia. Where diagnostic facilities are lacking, presumptive treatment of severely ill children is recommended. For other children, the continuation of feeding (by nasogastric tube if necessary) should be part of standard management.
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Affiliation(s)
- F H A Osier
- Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine Research, Coast, Kilifi District Hospital, PO Box 230, Kilifi, Kenya.
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Berkley JA, Ross A, Mwangi I, Osier FHA, Mohammed M, Shebbe M, Lowe BS, Marsh K, Newton CRJC. Prognostic indicators of early and late death in children admitted to district hospital in Kenya: cohort study. BMJ 2003; 326:361. [PMID: 12586667 PMCID: PMC148891 DOI: 10.1136/bmj.326.7385.361] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES To identify clinical indicators of immediate, early, and late mortality in children at admission to a sub-Saharan district hospital and to develop prognostic scores. DESIGN Prospective cohort study. SETTING One district hospital in Kenya. PARTICIPANTS Children aged over 90 days admitted to hospital from 1 July 1998 to 30 June 2001. MAIN OUTCOME MEASURES Prognostic indicators of mortality. RESULTS Of 8091 children admitted up to 1 June 2000, 436 (5%) died. Sixty (14%) died within four hours after admission (immediate), 193 (44%) after 4-48 hours (early), and 183 (42%) after 48 hours (late). There were marked differences in the clinical features associated with immediate, early, and late death. Seven indicators (neurological status, respiratory distress (subcostal indrawing or deep breathing), nutritional status (wasting or kwashiorkor), severe anaemia, jaundice, axillary temperature, and length of history) were included in simplified prognostic scores. Data from 4802 children admitted from 1 July 2000 to 30 June 2001 were used to validate the scores. For simplified prognostic scores the areas under the receiver operating characteristic curves were 0.93 (95% confidence interval 0.92 to 0.94), 0.82 (0.80 to 0.83), and 0.82 (0.81 to 0.84) for immediate, early, and late death, respectively. CONCLUSION In children admitted to a sub-Saharan hospital, the prognostic indicators of early and late deaths differ but a small number of simple clinical signs predict outcome well.
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Affiliation(s)
- J A Berkley
- KEMRI Centre for Geographic Medicine Research (Coast), PO Box 230, Kilifi, Kenya.
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