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Walker IS, Dini S, Aitken EH, Damelang T, Hasang W, Alemu A, Jensen ATR, Rambhatla JS, Opi DH, Duffy MF, Takashima E, Harawa V, Tsuboi T, Simpson JA, Mandala W, Taylor TE, Seydel KB, Chung AW, Rogerson SJ. A systems serology approach to identifying key antibody correlates of protection from cerebral malaria in Malawian children. BMC Med 2024; 22:388. [PMID: 39267089 PMCID: PMC11396342 DOI: 10.1186/s12916-024-03604-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 09/03/2024] [Indexed: 09/14/2024] Open
Abstract
BACKGROUND Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) proteins are expressed on the surface of infected erythrocytes, mediating parasite sequestration in the vasculature. PfEMP1 is a major target of protective antibodies, but the features of the antibody response are poorly defined. METHODS In Malawian children with cerebral or uncomplicated malaria, we characterized the antibody response to 39 recombinant PfEMP1 Duffy binding like (DBL) domains or cysteine-rich interdomain regions (CIDRs) in detail, including measures of antibody classes, subclasses, and engagement with Fcγ receptors and complement. Using elastic net regularized logistic regression, we identified a combination of seven antibody targets and Fc features that best distinguished between children with cerebral and uncomplicated malaria. To confirm the role of the selected targets and Fc features, we measured antibody-dependent neutrophil and THP-1 cell phagocytosis of intercellular adhesion molecule-1 (ICAM-1) and endothelial protein C (EPCR) co-binding infected erythrocytes. RESULTS The selected features distinguished between children with cerebral and uncomplicated malaria with 87% accuracy (median, 80-96% interquartile range) and included antibody to well-characterized DBLβ3 domains and a less well-characterized CIDRγ12 domain. The abilities of antibodies to engage C1q and FcγRIIIb, rather than levels of IgG, correlated with protection. In line with a role of FcγRIIIb binding antibodies to DBLβ3 domains, antibody-dependent neutrophil phagocytosis of ICAM-1 and EPCR co-binding IE was higher in uncomplicated malaria (15% median, 8-38% interquartile range) compared to cerebral malaria (7%, 30-15%, p < 0.001). CONCLUSIONS Antibodies associated with protection from cerebral malaria target a subset of PfEMP1 domains. The Fc features of protective antibody response include engagement of FcγRIIIb and C1q, and ability to induce antibody-dependent neutrophil phagocytosis of infected erythrocytes. Identifying the targets and Fc features of protective immunity could facilitate the development of PfEMP1-based therapeutics for cerebral malaria.
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Affiliation(s)
- Isobel S Walker
- Department of Medicine, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Saber Dini
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Elizabeth H Aitken
- Department of Infectious Diseases, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Timon Damelang
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Wina Hasang
- Department of Infectious Diseases, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Agersew Alemu
- Department of Infectious Diseases, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Anja T R Jensen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Janavi S Rambhatla
- Department of Medicine, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - D Herbert Opi
- Department of Medicine, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Michael F Duffy
- Department of Medicine, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Visopo Harawa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Takafumi Tsuboi
- Division of Cell-Free Sciences, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Wilson Mandala
- Academy of Medical Sciences, Malawi University of Science and Technology, Thyolo, Malawi
| | - Terrie E Taylor
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
- College of Osteopathic Medicine, Michigan State University, East Lansing, USA
| | - Karl B Seydel
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
- College of Osteopathic Medicine, Michigan State University, East Lansing, USA
| | - Amy W Chung
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Stephen J Rogerson
- Department of Medicine, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia.
- Department of Infectious Diseases, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia.
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2
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Singh A, Boggiano C, Yin DE, Polakowski L, Majji SP, Leitner WW, Levy O, De Paris K. Precision adjuvants for pediatric vaccines. Sci Transl Med 2024; 16:eabq7378. [PMID: 39231242 DOI: 10.1126/scitranslmed.abq7378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 08/06/2024] [Indexed: 09/06/2024]
Abstract
Elucidating optimal vaccine adjuvants for harnessing age-specific immune pathways to enhance magnitude, breadth, and durability of immunogenicity remains a key gap area in pediatric vaccine design. A better understanding of age-specific adjuvants will inform precision discovery and development of safe and effective vaccines for protecting children from preventable infectious diseases.
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Affiliation(s)
- Anjali Singh
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - César Boggiano
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Dwight E Yin
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Laura Polakowski
- Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Sai P Majji
- Maternal and Pediatric Infectious Disease Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20817, USA
| | - Wolfgang W Leitner
- Division of Allergy, Immunology, and Transplantation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Ofer Levy
- Precision Vaccines Program, Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Kristina De Paris
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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3
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Wang LT, Idris AH, Kisalu NK, Crompton PD, Seder RA. Monoclonal antibodies to the circumsporozoite proteins as an emerging tool for malaria prevention. Nat Immunol 2024; 25:1530-1545. [PMID: 39198635 DOI: 10.1038/s41590-024-01938-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Accepted: 07/17/2024] [Indexed: 09/01/2024]
Abstract
Despite various public health strategies, malaria caused by Plasmodium falciparum parasites remains a major global health challenge that requires development of new interventions. Extended half-life human monoclonal antibodies targeting the P. falciparum circumsporozoite protein on sporozoites, the infective form of malaria parasites, prevent malaria in rodents and humans and have been advanced into clinical development. The protective epitopes on the circumsporozoite protein targeted by monoclonal antibodies have been defined. Cryogenic electron and multiphoton microscopy have enabled mechanistic structural and functional investigations of how antibodies bind to the circumsporozoite protein and neutralize sporozoites. Moreover, innovations in bioinformatics and antibody engineering have facilitated enhancement of antibody potency and durability. Here, we summarize the latest scientific advances in understanding how monoclonal antibodies to the circumsporozoite protein prevent malaria and highlight existing clinical data and future plans for how this emerging intervention can be used alone or alongside existing antimalarial interventions to control malaria across at-risk populations.
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Affiliation(s)
- Lawrence T Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Azza H Idris
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
- The Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA.
| | - Neville K Kisalu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- PATH's Center for Vaccine Innovation and Access, Washington, DC, USA
| | - Peter D Crompton
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Robert A Seder
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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4
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Kurtovic L, Feng G, Hysa A, Haghiri A, O'Flaherty K, Wines BD, Santano R, D'Andrea L, Drummer HE, Hogarth PM, Sacarlal J, Fowkes FJI, Simpson JA, Dobaño C, Beeson JG. Antibody mechanisms of protection against malaria in RTS,S-vaccinated children: a post-hoc serological analysis of phase 2 trial. THE LANCET. MICROBE 2024:100898. [PMID: 39127054 DOI: 10.1016/s2666-5247(24)00130-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 03/25/2024] [Accepted: 05/10/2024] [Indexed: 08/12/2024]
Abstract
BACKGROUND The RTS,S malaria vaccine is currently recommended for children aged 5-6 months in regions with moderate-to-high Plasmodium falciparum transmission. However, vaccination only confers 55% efficacy over 12 months and wanes within 18 months. The immunological mechanisms of RTS,S-mediated immunity are poorly understood; therefore, we aimed to identify antibody response types associated with protection against malaria in children vaccinated with RTS,S. METHODS In this post-hoc analysis, we evaluated antibody responses in 737 children aged 1-4 years vaccinated with RTS,S in a phase 2b clinical trial conducted in Mozambique in 2003. We evaluated all available samples collected from children 30 days after the three-dose vaccination schedule at study month 3 (M3; n=737 available of 803 children allocated to receive RTS,S). For comparison, we tested a subset of samples collected before vaccination at study month 0 (M0; n=50) and from children in the control vaccine group (M0 n=25; M3 n=99). We quantified the induction of antibodies to different regions of the vaccine antigen that function by fixing serum complement proteins and binding to Fcγ receptors (FcγRs; FcγRI, FcγRIIa, and FcγRIII) expressed on immune cells as potential mechanisms of immunity. FINDINGS Functional antibody responses to the C-terminal region of the vaccine antigen, circumsporozoite protein (CSP), were associated with a reduced risk of malaria (C1q p=0·0060, FcγRIIa p=0·014, and FcγRIII p=0·019). These associations remained significant in male participants when the analyses were stratified by sex (C1q p=0·012, FcγRI p=0·023, FcγRIIa p=0·0070, and FcγRIII p=0·0080). IgA to the central repeat (p=0·0010) and C-terminal (p=0·0040) regions of CSP were also associated with protection. We show that IgA can bind FcαRI and mediate opsonic phagocytosis using a serum pool and monoclonal antibodies. Multiparameter analysis using machine-learning methods suggest that IgA, complement fixation, and FcγRI binding were most predictive of protection against malaria (hazard ratio <1) and suggested that associations differed between male and female participants. INTERPRETATION We provide evidence that functional antibody responses mediated by IgG and IgA are associated with protection against malaria in young children vaccinated with RTS,S, and suggest potential differences in the correlates of immunity between males and females. These findings reveal new avenues that could be used to achieve malaria vaccines with higher efficacy. FUNDING National Health and Medical Research Council, Australia, and Thrasher Research Fund.
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Affiliation(s)
- Liriye Kurtovic
- Burnet Institute, Melbourne, VIC, Australia; Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Gaoqian Feng
- Burnet Institute, Melbourne, VIC, Australia; Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
| | - Alessia Hysa
- Burnet Institute, Melbourne, VIC, Australia; Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
| | - Ali Haghiri
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia; School of Engineering, University of Leicester, Leicester, UK
| | | | - Bruce D Wines
- Burnet Institute, Melbourne, VIC, Australia; Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia; Department of Clinical Pathology, The University of Melbourne, Melbourne, VIC, Australia
| | - Rebeca Santano
- ISGlobal, Hospital Clínic Universitat de Barcelona, Barcelona, Catalonia, Spain; CIBER Enfermedades Infecciosas, Barcelona, Spain
| | | | - Heidi E Drummer
- Burnet Institute, Melbourne, VIC, Australia; Department of Microbiology, Monash University, Melbourne, VIC, Australia; Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia
| | - P Mark Hogarth
- Burnet Institute, Melbourne, VIC, Australia; Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia; Department of Clinical Pathology, The University of Melbourne, Melbourne, VIC, Australia
| | - Jahit Sacarlal
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique; Faculdade de Medicina, Universidade Eduardo Mondlane, Maputo, Mozambique
| | - Freya J I Fowkes
- Burnet Institute, Melbourne, VIC, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Carlota Dobaño
- ISGlobal, Hospital Clínic Universitat de Barcelona, Barcelona, Catalonia, Spain; CIBER Enfermedades Infecciosas, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia; Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia; Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia; Department of Microbiology and Immunology, The University of Melbourne, Melbourne, VIC, Australia.
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5
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Duffy PE, Gorres JP, Healy SA, Fried M. Malaria vaccines: a new era of prevention and control. Nat Rev Microbiol 2024:10.1038/s41579-024-01065-7. [PMID: 39025972 DOI: 10.1038/s41579-024-01065-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2024] [Indexed: 07/20/2024]
Abstract
Malaria killed over 600,000 people in 2022, a death toll that has not improved since 2015. Additionally, parasites and mosquitoes resistant to existing interventions are spreading across Africa and other regions. Vaccines offer hope to reduce the mortality burden: the first licensed malaria vaccines, RTS,S and R21, will be widely deployed in 2024 and should substantially reduce childhood deaths. In this Review, we provide an overview of the malaria problem and the Plasmodium parasite, then describe the RTS,S and R21 vaccines (the first vaccines for any human parasitic disease), summarizing their benefits and limitations. We explore next-generation vaccines designed using new knowledge of malaria pathogenesis and protective immunity, which incorporate antigens and platforms to elicit effective immune responses against different parasite stages in human or mosquito hosts. We describe a decision-making process that prioritizes malaria vaccine candidates for development in a resource-constrained environment. Future vaccines might improve upon the protective efficacy of RTS,S or R21 for children, or address the wider malaria scourge by preventing pregnancy malaria, reducing the burden of Plasmodium vivax or accelerating malaria elimination.
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Affiliation(s)
- Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - J Patrick Gorres
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sara A Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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6
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Lv Y, Wu S, Nie Q, Liu S, Xu W, Chen G, Du Y, Chen J. Extracellular vesicles derived from plasmodium-infected red blood cells alleviate cerebral malaria in plasmodium berghei ANKA-infected C57BL/6J mice. Int Immunopharmacol 2024; 132:111982. [PMID: 38569430 DOI: 10.1016/j.intimp.2024.111982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 03/15/2024] [Accepted: 03/28/2024] [Indexed: 04/05/2024]
Abstract
RTS,S is the first malaria vaccine recommended for implementation among young children at risk. However, vaccine efficacy is modest and short-lived. To mitigate the risk of cerebral malaria (CM) among children under the age of 5, it is imperative to develop new vaccines. EVs are potential vaccine candidates as they obtain the ability of brain-targeted delivery and transfer plasmodium antigens and immunomodulators during infections. This study extracted EVs from BALB/c mice infected with Plasmodium yoelii 17XNL (P.y17XNL). C57BL/6J mice were intravenously immunized with EVs (EV-I.V. + CM group) or subcutaneously vaccinated with the combination of EVs and CpG ODN-1826 (EV + CPG ODN-S.C. + CM group) on days 0 and 20, followed by infection with Plasmodium berghei ANKA (P.bANKA) on day 20 post-second immunization. We monitored Parasitemia and survival rate. The integrity of the Blood-brain barrier (BBB) was examined using Evans blue staining.The levels of cytokines and adhesion molecules were evaluated using Luminex, RT-qPCR, and WB. Brain pathology was evaluated by hematoxylin and eosin and immunohistochemical staining. The serum levels of IgG, IgG1, and IgG2a were analyzed by enzyme-linked immunosorbent assay. Compared with those in the P.bANKA-infected group, parasitemia increased slowly, death was delayed (day 10 post-infection), and the survival rate reached 75 %-83.3 % in the EV-I.V. + ECM and EV + CPG ODN-S.C. + ECM groups. Meanwhile, compared with the EV + CPG ODN-S.C. + ECM group, although parasitemia was almost the same, the survival rate increased in the EV-I.V. + ECM group.Additionally, EVs immunization markedly downregulated inflammatory responses in the spleen and brain and ameliorated brain pathological changes, including BBB disruption and infected red blood cell (iRBC) sequestration. Furthermore, the EVs immunization group exhibited enhanced antibody responses (upregulation of IgG1 and IgG2a production) compared to the normal control group. EV immunization exerted protective effects, improving the integrity of the BBB, downregulating inflammation response of brain tissue, result in reduces the incidence of CM. The protective effects were determined by immunological pathways and brain targets elicited by EVs. Intravenous immunization exhibited better performance than subcutaneous immunization, which perhaps correlated with EVs, which can naturally cross BBB to play a better role in brain protection.
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Affiliation(s)
- Yinyi Lv
- Taizhou Central Hospital (Taizhou University Hospital), Taizhou University, No 1139 Shifu Road, Jiaojiang District, Taizhou 318000, China
| | - Shuang Wu
- Taizhou Central Hospital (Taizhou University Hospital), Taizhou University, No 1139 Shifu Road, Jiaojiang District, Taizhou 318000, China
| | - Qing Nie
- Weifang Centers for Disease Control and Prevention, No 4801 Huixian Road, Gaoxin Distric, Weifang 261061, Shandong Province, China
| | - Shuangchun Liu
- Municipal Hospital Affiliated to Medical School of Taizhou University, No 381, Zhongshan East Road, Jiaojiang District, Taizhou 318000, China
| | - Wenxin Xu
- Taizhou Central Hospital (Taizhou University Hospital), Taizhou University, No 1139 Shifu Road, Jiaojiang District, Taizhou 318000, China
| | - Guang Chen
- Taizhou Central Hospital (Taizhou University Hospital), Taizhou University, No 1139 Shifu Road, Jiaojiang District, Taizhou 318000, China.
| | - Yunting Du
- Department of Laboratory Medicine, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, NO. 44 Xiaoheyan Road, Dadong District, Shenyang 110042, China.
| | - Jinguang Chen
- Taizhou Central Hospital (Taizhou University Hospital), Taizhou University, No 1139 Shifu Road, Jiaojiang District, Taizhou 318000, China.
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7
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Dobbs KR, Atieli HE, Valim C, Beeson JG. Previous Malaria Exposures and Immune Dysregulation: Developing Strategies To Improve Malaria Vaccine Efficacy in Young Children. Am J Trop Med Hyg 2024; 110:627-630. [PMID: 38442424 PMCID: PMC10993830 DOI: 10.4269/ajtmh.23-0696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/06/2023] [Indexed: 03/07/2024] Open
Abstract
After several decades in development, two malaria vaccines based on the same antigen and with very similar constructs and adjuvants, RTS,S/AS01 (RTS,S) and R21/Matrix-M (R21), were recommended by the WHO for widespread vaccination of children. These vaccines are much-needed additions to malaria control programs that, when used in conjunction with other control measures, will help to accelerate reductions in malaria morbidity and mortality. Although R21 is not yet available, RTS,S is currently being integrated into routine vaccine schedules in some areas. However, the efficacy of RTS,S is partial, short-lived, and varies widely according to age and geographic location. It is not clear why RTS,S induces protection in some individuals and not others, what the immune mechanisms are that favor protective immunity with RTS,S, and how immune mechanisms are influenced by host and environmental factors. Several studies suggest that higher levels of previous malaria exposure negatively impact RTS,S clinical efficacy. In this article, we summarize data suggesting that previous malaria exposures negatively impact the efficacy of RTS,S and other malaria vaccine candidates. We highlight recent evidence suggesting that increasing malaria exposure impairs the generation of functional antibody responses to RTS,S. Finally, we discuss how investigation of clinical and immune factors associated with suboptimal responses to RTS,S can be used to develop strategies to optimize RTS,S, which will remain relevant to R21 and next-generation vaccines.
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Affiliation(s)
| | | | - Clarissa Valim
- Boston University School of Public Health, Boston, Massachusetts
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8
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Palacpac NMQ, Ishii KJ, Arisue N, Tougan T, Horii T. Immune tolerance caused by repeated P. falciparum infection against SE36 malaria vaccine candidate antigen and the resulting limited polymorphism. Parasitol Int 2024; 99:102845. [PMID: 38101534 DOI: 10.1016/j.parint.2023.102845] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/27/2023] [Accepted: 12/10/2023] [Indexed: 12/17/2023]
Abstract
The call for second generation malaria vaccines needs not only the identification of novel candidate antigens or adjuvants but also a better understanding of immune responses and the underlying protective processes. Plasmodium parasites have evolved a range of strategies to manipulate the host immune system to guarantee survival and establish parasitism. These immune evasion strategies hamper efforts to develop effective malaria vaccines. In the case of a malaria vaccine targeting the N-terminal domain of P. falciparum serine repeat antigen 5 (SE36), now in clinical trials, we observed reduced responsiveness (lowered immunogenicity) which may be attributed to immune tolerance/immune suppression. Here, immunogenicity data and insights into the immune responses to SE36 antigen from epidemiological studies and clinical trials are summarized. Documenting these observations is important to help identify gaps for SE36 continued development and engender hope that highly effective blood-stage/multi-stage vaccines can be achieved.
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Affiliation(s)
- Nirianne Marie Q Palacpac
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Ken J Ishii
- Center for Vaccine and Adjuvant Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Osaka 567-0085, Japan; Laboratory of Vaccine Science, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan; Division of Vaccine Science, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan.
| | - Nobuko Arisue
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Takahiro Tougan
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
| | - Toshihiro Horii
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
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9
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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] [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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10
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Powell TJ, Tang J, Mitchell R, DeRome ME, Jacobs A, Palath N, Cardenas E, Yorke M, Boyd JG, Kaba SA, Nardin E. Immunogenicity, Efficacy, and Safety of a Novel Synthetic Microparticle Pre-Erythrocytic Malaria Vaccine in Multiple Host Species. Vaccines (Basel) 2023; 11:1789. [PMID: 38140193 PMCID: PMC10748200 DOI: 10.3390/vaccines11121789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023] Open
Abstract
We previously reported a protective antibody response in mice immunized with synthetic microparticle vaccines made using layer-by-layer fabrication (LbL-MP) and containing the conserved T1BT* epitopes from the P. falciparum circumsporozoite protein. To further optimize the vaccine candidate, a benchtop tangential flow filtration method (LbL-by-TFF) was developed and utilized to produce vaccine candidates that differed in the status of base layer crosslinking, inclusion of a TLR2 ligand in the antigenic peptide, and substitution of serine or alanine for an unpaired cysteine residue in the T* epitope. Studies in mice revealed consistent superiority of the Pam3Cys-modified candidates and a modest benefit of base layer crosslinking, as evidenced by higher and more persistent antibody titers (up to 18 months post-immunization), a qualitative improvement of T-cell responses toward a Th1 phenotype, and greater protection from live parasite challenges compared to the unmodified prototype candidate. Immunogenicity was also tested in a non-human primate model, the rhesus macaque. Base layer-crosslinked LbL-MP loaded with T1BT* peptide with or without covalently linked Pam3Cys elicited T1B-specific antibody responses and T1BT*-specific T-cell responses dominated by IFNγ secretion with lower levels of IL-5 secretion. The Pam3Cys-modified construct was more potent, generating antibody responses that neutralized wild-type P. falciparum in an in vitro hepatocyte invasion assay. IgG purified from individual macaques immunized with Pam3Cys.T1BT* LbL-MP protected naïve mice from challenges with transgenic P. berghei sporozoites that expressed the full-length PfCS protein, with 50-88% of passively immunized mice parasite-free for ≥15 days. Substitution of serine for an unpaired cysteine in the T* region of the T1BT* subunit did not adversely impact immune potency in the mouse while simplifying the manufacture of the antigenic peptide. In a Good Laboratory Practices compliant rabbit toxicology study, the base layer-crosslinked, Pam3Cys-modified, serine-substituted candidate was shown to be safe and immunogenic, eliciting parasite-neutralizing antibody responses and establishing the dose/route/regimen for a clinical evaluation of this novel synthetic microparticle pre-erythrocytic malaria vaccine candidate.
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Affiliation(s)
- Thomas J. Powell
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
| | - Jie Tang
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
| | - Robert Mitchell
- Department of Microbiology, School of Medicine, New York University, New York, NY 10010, USA; (R.M.); (E.N.)
| | - Mary E. DeRome
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
- Multiple Myeloma Research Foundation, 383 Main Avenue, 5th Floor, Norwalk, CT 06851, USA
| | - Andrea Jacobs
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
| | - Naveen Palath
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
- Pfizer, Inc., Andover, MA 01810, USA
| | - Edwin Cardenas
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
| | - Michelle Yorke
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
| | - James G. Boyd
- Artificial Cell Technologies, Inc., 5 Science Park, Suite 13, New Haven, CT 06511, USA; (J.T.); (M.E.D.); (A.J.); (N.P.); (E.C.); (M.Y.); (J.G.B.)
| | - Stephen A. Kaba
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA;
- GreenLight Biosciences, Inc., Lexington, MA 02421, USA
| | - Elizabeth Nardin
- Department of Microbiology, School of Medicine, New York University, New York, NY 10010, USA; (R.M.); (E.N.)
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11
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Abstract
Malaria is a mosquito-borne disease caused by protozoan parasites of the genus Plasmodium. Despite significant declines in malaria-attributable morbidity and mortality over the last two decades, it remains a major public health burden in many countries. This underscores the critical need for improved strategies to prevent, treat and control malaria if we are to ultimately progress towards the eradication of this disease. Ideally, this will include the development and deployment of a highly effective malaria vaccine that is able to induce long-lasting protective immunity. There are many malaria vaccine candidates in development, with more than a dozen of these in clinical development. RTS,S/AS01 (also known as Mosquirix) is the most advanced malaria vaccine and was shown to have modest efficacy against clinical malaria in phase III trials in 5- to 17-month-old infants. Following pilot implementation trials, the World Health Organisation has recommended it for use in Africa in young children who are most at risk of infection with P. falciparum, the deadliest of the human malaria parasites. It is well recognised that more effective malaria vaccines are needed. In this review, we discuss malaria vaccine candidates that have progressed into clinical evaluation and highlight the most advanced candidates: Sanaria's irradiated sporozoite vaccine (PfSPZ Vaccine), the chemoattenuated sporozoite vaccine (PfSPZ-CVac), RTS,S/AS01 and the novel malaria vaccine candidate, R21, which displayed promising, high-level efficacy in a recent small phase IIb trial in Africa.
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Affiliation(s)
- Danielle I Stanisic
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia.
| | - Michael F Good
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, QLD, Australia.
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12
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Bell GJ, Gyaase S, Goel V, Adu B, Mensah B, Essone P, Dosoo D, Osei M, Niare K, Wiru K, Brandt K, Emch M, Ghansah A, Asante KP, Mvalo T, Agnandji ST, Juliano JJ, Bailey JA. Background malaria incidence and parasitemia during the three-dose RTS,S/AS01 vaccination series do not reduce magnitude of antibody response nor efficacy against the first case of malaria. BMC Infect Dis 2023; 23:716. [PMID: 37872492 PMCID: PMC10594884 DOI: 10.1186/s12879-023-08699-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/11/2023] [Indexed: 10/25/2023] Open
Abstract
BACKGROUND RTS,S/AS01 has been recommended by WHO for widespread implementation in medium to high malaria transmission settings. Previous analyses have noted lower vaccine efficacies in higher transmission settings, possibly due to the more rapid development of naturally acquired immunity in the control group. METHODS To investigate a reduced immune response to vaccination as a potential mechanism behind lower efficacy in high transmission areas, we examine initial vaccine antibody (anti-CSP IgG) response and vaccine efficacy against the first case of malaria (to exclude the effect of naturally acquired immunity) using data from three study areas (Kintampo, Ghana; Lilongwe, Malawi; Lambaréné, Gabon) from the 2009-2014 phase III trial (NCT00866619). Our key exposures are parasitemia during the vaccination series and background malaria incidence. We calculate vaccine efficacy (one minus hazard ratio) using a cox-proportional hazards model and allowing for the time-varying effect of RTS,S/AS01. RESULTS We find that antibody responses to the primary three-dose vaccination series were higher in Ghana than in Malawi and Gabon, but that neither antibody levels nor vaccine efficacy against the first case of malaria varied by background incidence or parasitemia during the primary vaccination series. CONCLUSIONS We find that vaccine efficacy is unrelated to infections during vaccination. Contributing to a conflicting literature, our results suggest that vaccine efficacy is also unrelated to infections before vaccination, meaning that control-group immunity is likely a major reason for lower efficacy in high transmission settings, not reduced immune responses to RTS,S/AS01. This may be reassuring for implementation in high transmission settings, though further studies are needed.
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Affiliation(s)
- Griffin J Bell
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA.
| | | | - Varun Goel
- Carolina Population Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Bright Adu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Benedicta Mensah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Paulin Essone
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - David Dosoo
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Musah Osei
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Karamoko Niare
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, 02912, USA
| | - Kenneth Wiru
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Katerina Brandt
- Carolina Population Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA
- Carolina Population Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Anita Ghansah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | - Tisungane Mvalo
- University of North Carolina Project, Lilongwe, Malawi
- Department of Pediatrics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Jonathan J Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, 02912, USA
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13
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Bell GJ, Gyaase S, Goel V, Adu B, Mensah B, Essone P, Dosoo D, Osei M, Niare K, Wiru K, Brandt K, Emch M, Ghansah A, Asante KP, Mvalo T, Agnandji ST, Juliano JJ, Bailey JA. Malaria Transmission Intensity and Parasitemia during the Three-Dose RTS,S/AS01 Vaccination Series do not Reduce Magnitude of Antibody Response nor Efficacy Against the First Case of Malaria. RESEARCH SQUARE 2023:rs.3.rs-2960373. [PMID: 37292711 PMCID: PMC10246269 DOI: 10.21203/rs.3.rs-2960373/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background RTS,S/AS01 has been recommended by WHO for widespread implementation in medium to high malaria transmission settings. Previous analyses have noted lower vaccine efficacies in higher transmission settings, possibly due to the more rapid development of naturally acquired immunity in the control group. Methods To investigate a reduced immune response to vaccination as a potential mechanism behind lower efficacy in high transmission areas, we examine initial vaccine antibody (anti-CSP IgG) response and vaccine efficacy against the first case of malaria to exclude the delayed malaria effect using data from three study areas (Kintampo, Ghana; Lilongwe, Malawi; Lambaréné, Gabon) from the 2009-2014 phase III trial (NCT00866619). Our key exposures are parasitemia during the vaccination series and malaria transmission intensity. We calculate vaccine efficacy (one minus hazard ratio) using a cox-proportional hazards model and allowing for the time-varying effect of RTS,S/AS01. Results We find that antibody responses to the primary three-dose vaccination series were higher in Ghana than in Malawi and Gabon, but that neither antibody levels nor vaccine efficacy against the first case of malaria varied by transmission intensity or parasitemia during the primary vaccination series. Conclusions We find that vaccine efficacy is unrelated to infections during vaccination. Contributing to a conflicting literature, our results suggest that vaccine efficacy is also unrelated to infections before vaccination, meaning that delayed malaria is likely the main reason for lower efficacy in high transmission settings, not reduced immune responses. This may be reassuring for implementation in high transmission settings, though further studies are needed.
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14
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Beeson JG, Kurtovic L, Valim C, Asante KP, Boyle MJ, Mathanga D, Dobano C, Moncunill G. The RTS,S malaria vaccine: Current impact and foundation for the future. Sci Transl Med 2022; 14:eabo6646. [DOI: 10.1126/scitranslmed.abo6646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The RTS,S vaccine has recently been recommended for implementation as a childhood vaccine in regions with moderate-to-high malaria transmission. We discuss mechanisms of vaccine protection and longevity, implementation considerations, and future research needed to increase the vaccine’s health impact, including vaccine modifications for higher efficacy and longevity of protection.
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Affiliation(s)
- James G. Beeson
- Burnet Institute, Melbourne 3004, Victoria, Australia
- Department of Infectious Diseases, University of Melbourne, Victoria, Australia
- Monash University, Central Clinical School and Department of Microbiology, Victoria, Australia
| | - Liriye Kurtovic
- Burnet Institute, Melbourne 3004, Victoria, Australia
- Monash University, Central Clinical School and Department of Microbiology, Victoria, Australia
| | - Clarissa Valim
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
| | - Kwaku Poku Asante
- Kintampo Health Research Centre, Kintampo North Municipality, Bono East Region, Ghana
| | - Michelle J. Boyle
- QIMR Berghofer Institute, Herston, Queensland, Australia
- University of Queensland, School of Biomedical Sciences, St Lucia, Queensland, Australia
- Griffith University, Brisbane, Queensland, Australia
| | - Don Mathanga
- Malaria Alert Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Carlota Dobano
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia, Spain
- CIBER Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Gemma Moncunill
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Catalonia, Spain
- CIBER Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
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