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Gbaguidi MLE, Adamou R, Edslev S, Hansen A, Domingo ND, Dechavanne C, Massougbodji A, Garcia A, Theisen M, Milet J, Donadi EA, Courtin D. IgG and IgM responses to the Plasmodium falciparum asexual stage antigens reflect respectively protection against malaria during pregnancy and infanthood. Malar J 2024; 23:154. [PMID: 38764069 PMCID: PMC11103834 DOI: 10.1186/s12936-024-04970-7] [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: 12/15/2023] [Accepted: 04/29/2024] [Indexed: 05/21/2024] Open
Abstract
BACKGROUND Plasmodium falciparum malaria is a public health issue mostly seen in tropical countries. Until now, there is no effective malaria vaccine against antigens specific to the blood-stage of P. falciparum infection. Because the pathogenesis of malarial disease results from blood-stage infection, it is essential to identify the most promising blood-stage vaccine candidate antigens under natural exposure to malaria infection. METHODS A cohort of 400 pregnant women and their infants was implemented in South Benin. An active and passive protocol of malaria surveillance was established during pregnancy and infancy to precisely ascertain malaria infections during the follow-up. Twenty-eight antibody (Ab) responses specific to seven malaria candidate vaccine antigens were repeatedly quantified during pregnancy (3 time points) and infancy (6 time points) in order to study the Ab kinetics and their protective role. Abs were quantified by ELISA and logistic, linear and cox-proportional hazard model were performed to analyse the associations between Ab responses and protection against malaria in mothers and infants, taking into account socio-economic factors and for infants an environmental risk of exposure. RESULTS The levels of IgM against MSP1, MSP2 and MSP3 showed an early protective response against the onset of symptomatic malaria infections starting from the 18th month of life, whereas no association was found for IgG responses during infancy. In women, some IgG responses tend to be associated with a protection against malaria risk along pregnancy and at delivery, among them IgG3 against GLURP-R0 and IgG2 against MSP1. CONCLUSION The main finding suggests that IgM should be considered in vaccine designs during infanthood. Investigation of the functional role played by IgM in malaria protection needs further attention.
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Affiliation(s)
- Mahugnon L Erasme Gbaguidi
- Division of Clinical Immunology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- IRD, MERIT, Université Paris Cité, 75006, Paris, France
- Centre d'Etude Et de Recherche Sur Les Pathologies Associées À La Grossesse Et À L'Enfance, Cotonou, Bénin
| | - Rafiou Adamou
- IRD, MERIT, Université Paris Cité, 75006, Paris, France
- Centre d'Etude Et de Recherche Sur Les Pathologies Associées À La Grossesse Et À L'Enfance, Cotonou, Bénin
| | - Sofie Edslev
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Benin
| | - Anita Hansen
- Institut de Recherche Clinique du Bénin, Abomey-Calavi, Benin
| | - Nadia D Domingo
- Centre d'Etude Et de Recherche Sur Les Pathologies Associées À La Grossesse Et À L'Enfance, Cotonou, Bénin
| | | | | | - André Garcia
- IRD, MERIT, Université Paris Cité, 75006, Paris, France
| | - Michael Theisen
- Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | | | - Eduardo A Donadi
- Division of Clinical Immunology, Department of Medicine, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - David Courtin
- IRD, MERIT, Université Paris Cité, 75006, Paris, France.
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2
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Thomson-Luque R, Stabler TC, Fürle K, Silva JC, Daubenberger C. Plasmodium falciparum merozoite surface protein 1 as asexual blood stage malaria vaccine candidate. Expert Rev Vaccines 2024; 23:160-173. [PMID: 38100310 DOI: 10.1080/14760584.2023.2295430] [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: 09/25/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023]
Abstract
INTRODUCTION Malaria represents a public health challenge in tropical and subtropical regions, and currently deployed control strategies are likely insufficient to drive elimination of malaria. Development and improvement of malaria vaccines might be key to reduce disease burden. Vaccines targeting asexual blood stages of the parasite have shown limited efficacy when studied in human trials conducted over the past decades. AREAS COVERED Vaccine candidates based on the merozoite surface protein 1 (MSP1) were initially envisioned as one of the most promising approaches to provide immune protection against asexual blood-stage malaria. Successful immunization studies in monkey involved the use of the full-length MSP1 (MSP1FL) as vaccine construct. Vaccines using MSP1FL for immunization have the potential benefit of including numerous conserved B-cell and T-cell epitopes. This could result in improved parasite strain-transcending, protective immunity in the field. We review outcomes of clinical trials that utilized a variety of MSP1 constructs and formulations, including MSP1FL, either alone or in combination with other antigens, in both animal models and humans. EXPERT OPINION Novel approaches to analyze breadth and magnitude of effector functions of MSP1-targeting antibodies in volunteers undergoing experimental vaccination and controlled human malaria infection will help to define correlates of protective immunity.
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Affiliation(s)
- Richard Thomson-Luque
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
- Sumaya-Biotech GmbH & Co. KG Heidelberg, Germany
| | - Thomas C Stabler
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
| | - Kristin Fürle
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (GHTM IHMT, UNL), Lisbon, Portugal
| | - Claudia Daubenberger
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
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3
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Walker IS, Rogerson SJ. Pathogenicity and virulence of malaria: Sticky problems and tricky solutions. Virulence 2023; 14:2150456. [PMID: 36419237 PMCID: PMC9815252 DOI: 10.1080/21505594.2022.2150456] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/25/2022] Open
Abstract
Infections with Plasmodium falciparum and Plasmodium vivax cause over 600,000 deaths each year, concentrated in Africa and in young children, but much of the world's population remain at risk of infection. In this article, we review the latest developments in the immunogenicity and pathogenesis of malaria, with a particular focus on P. falciparum, the leading malaria killer. Pathogenic factors include parasite-derived toxins and variant surface antigens on infected erythrocytes that mediate sequestration in the deep vasculature. Host response to parasite toxins and to variant antigens is an important determinant of disease severity. Understanding how parasites sequester, and how antibody to variant antigens could prevent sequestration, may lead to new approaches to treat and prevent disease. Difficulties in malaria diagnosis, drug resistance, and specific challenges of treating P. vivax pose challenges to malaria elimination, but vaccines and other preventive strategies may offer improved disease control.
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Affiliation(s)
- Isobel S Walker
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
| | - Stephen J Rogerson
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
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4
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Mortazavi SE, Lugaajju A, Nylander M, Danielsson L, Tijani MK, Beeson JG, Persson KEM. Acquisition of complement fixing antibodies targeting Plasmodium falciparum merozoites in infants and their mothers in Uganda. Front Immunol 2023; 14:1295543. [PMID: 38090561 PMCID: PMC10715273 DOI: 10.3389/fimmu.2023.1295543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 11/10/2023] [Indexed: 12/18/2023] Open
Abstract
Background Antibody-mediated complement fixation has previously been associated with protection against malaria in naturally acquired immunity. However, the process of early-life development of complement-fixing antibodies in infants, both in comparison to their respective mothers and to other immune parameters, remains less clear. Results We measured complement-fixing antibodies in newborns and their mothers in a malaria endemic area over 5 years follow-up and found that infants' complement-fixing antibody levels were highest at birth, decreased until six months, then increased progressively until they were similar to birth at five years. Infants with high levels at birth experienced a faster decay of complement-fixing antibodies but showed similar levels to the low response group of newborns thereafter. No difference was observed in antibody levels between infant cord blood and mothers at delivery. The same result was found when categorized into high and low response groups, indicating placental transfer of antibodies. Complement-fixing antibodies were positively correlated with total schizont-specific IgG and IgM levels in mothers and infants at several time points. At nine months, complement-fixing antibodies were negatively correlated with total B cell frequency and osteopontin concentrations in the infants, while positively correlated with atypical memory B cells and P. falciparum-positive atypical memory B cells. Conclusion This study indicates that complement-fixing antibodies against P. falciparum merozoites are produced in the mothers and placentally-transferred, and they are acquired in infants over time during the first years of life. Understanding early life immune responses is crucial for developing a functional, long lasting malaria vaccine.
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Affiliation(s)
- Susanne E. Mortazavi
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Department of Infectious Diseases, Skåne University Hospital, Lund, Sweden
| | - Allan Lugaajju
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Maria Nylander
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Lena Danielsson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Clinical Chemistry and Pharmacology, Laboratory Medicine, Office for Medical Services, Region Skåne, Lund, Sweden
| | - Muyideen Kolapo Tijani
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Cellular Parasitology Program, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - James G. Beeson
- The Burnet Institute, Melbourne, VIC, Australia
- Department of Infectious Diseases, University of Melbourne, Melbourne, VIC, Australia
- Central Clinical School and Department of Microbiology, Monash University, Melbourne, VIC, Australia
| | - Kristina E. M. Persson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Clinical Chemistry and Pharmacology, Laboratory Medicine, Office for Medical Services, Region Skåne, Lund, Sweden
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5
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Plaza DF, Zerebinski J, Broumou I, Lautenbach MJ, Ngasala B, Sundling C, Färnert A. A genomic platform for surveillance and antigen discovery in Plasmodium spp. using long-read amplicon sequencing. CELL REPORTS METHODS 2023; 3:100574. [PMID: 37751696 PMCID: PMC10545912 DOI: 10.1016/j.crmeth.2023.100574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 06/18/2023] [Accepted: 08/07/2023] [Indexed: 09/28/2023]
Abstract
Many vaccine candidate proteins in the malaria parasite Plasmodium falciparum are under strong immunological pressure and confer antigenic diversity. We present a sequencing and data analysis platform for the genomic surveillance of the insertion or deletion (indel)-rich antigens merozoite surface protein 1 (MSP1), MSP2, glutamate-rich protein (GLURP), and CSP from P. falciparum using long-read circular consensus sequencing (CCS) in multiclonal malaria isolates. Our platform uses 40 PCR primers per gene to asymmetrically barcode and identify multiclonal infections in pools of up to 384 samples. With msp2, we validated the method using 235 mock infections combining 10 synthetic variants at different concentrations and infection complexities. We applied this strategy to P. falciparum isolates from a longitudinal cohort in Tanzania. Finally, we constructed an analysis pipeline that streamlines the processing and interpretation of epidemiological and antigenic diversity data from demultiplexed FASTQ files. This platform can be easily adapted to other polymorphic antigens of interest in Plasmodium or any other human pathogen.
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Affiliation(s)
- David Fernando Plaza
- Division of Infectious Diseases, Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden.
| | - Julia Zerebinski
- Division of Infectious Diseases, Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Ioanna Broumou
- Division of Infectious Diseases, Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Maximilian Julius Lautenbach
- Division of Infectious Diseases, Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Billy Ngasala
- Muhimbili University of Health and Allied Sciences, Dar es Salaam 57RF+V8, Tanzania
| | - Christopher Sundling
- Division of Infectious Diseases, Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, 17176 Stockholm, Sweden
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6
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Rosenkranz M, Fürle K, Hibbert J, Ulmer A, Ali A, Giese T, Blank A, Haefeli WE, Böhnlein E, Lanzer M, Thomson-Luque R. Multifunctional IgG/IgM antibodies and cellular cytotoxicity are elicited by the full-length MSP1 SumayaVac-1 malaria vaccine. NPJ Vaccines 2023; 8:112. [PMID: 37558673 PMCID: PMC10412566 DOI: 10.1038/s41541-023-00701-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 06/27/2023] [Indexed: 08/11/2023] Open
Abstract
Radical control of malaria likely requires a vaccine that targets both the asymptomatic liver stages and the disease-causing blood stages of the human malaria parasite Plasmodium falciparum. While substantial progress has been made towards liver stage vaccines, the development of a blood stage vaccine is lagging behind. We have recently conducted a first-in-human clinical trial to evaluate the safety and immunogenicity of the recombinant, full-length merozoite surface protein 1 (MSP1FL) formulated with GLA-SE as adjuvant. Here, we show that the vaccine, termed SumayaVac-1, elicited both a humoral and cellular immune response as well as a recall T cell memory. The induced IgG and IgM antibodies were able to stimulate various Fc-mediated effector mechanisms associated with protection against malaria, including phagocytosis, release of reactive oxygen species, production of IFN-γ as well as complement activation and fixation. The multifunctional activity of the humoral immune response remained for at least 6 months after vaccination and was comparable to that of naturally acquired anti-MSP1 antibodies from semi-immune adults from Kenya. We further present evidence of SumayaVac-1 eliciting a recallable cellular cytotoxicity by IFN-γ producing CD8+ T cells. Our study revitalizes MSP1FL as a relevant blood stage vaccine candidate and warrants further evaluation of SumayaVac-1 in a phase II efficacy trial.
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Affiliation(s)
- Micha Rosenkranz
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Kristin Fürle
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Julia Hibbert
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Anne Ulmer
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Arin Ali
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Thomas Giese
- Institute for Immunology, Heidelberg University Hospital and German Center for Infection Research (DZIF), Heidelberg, Germany
| | - Antje Blank
- Clinical Pharmacology and Pharmacoepidemiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Walter E Haefeli
- Clinical Pharmacology and Pharmacoepidemiology, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Michael Lanzer
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Richard Thomson-Luque
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany.
- Sumaya-Biotech GmbH & Co. KG, Heidelberg, Germany.
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7
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B-Cell Epitope Mapping of the Plasmodium falciparum Malaria Vaccine Candidate GMZ2.6c in a Naturally Exposed Population of the Brazilian Amazon. Vaccines (Basel) 2023; 11:vaccines11020446. [PMID: 36851323 PMCID: PMC9966924 DOI: 10.3390/vaccines11020446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
The GMZ2.6c malaria vaccine candidate is a multi-stage P. falciparum chimeric protein that contains a fragment of the sexual-stage Pfs48/45-6C protein genetically fused to GMZ2, an asexual-stage vaccine construction consisting of the N-terminal region of the glutamate-rich protein (GLURP) and the C-terminal region of the merozoite surface protein-3 (MSP-3). Previous studies showed that GMZ2.6c is widely recognized by antibodies from Brazilian exposed individuals and that its components are immunogenic in natural infection by P. falciparum. In addition, anti-GMZ2.6c antibodies increase with exposure to infection and may contribute to parasite immunity. Therefore, identifying epitopes of proteins recognized by antibodies may be an important tool for understanding protective immunity. Herein, we identify and validate the B-cell epitopes of GMZ2.6c as immunogenic and immunodominant in individuals exposed to malaria living in endemic areas of the Brazilian Amazon. Specific IgG antibodies and subclasses against MSP-3, GLURP, and Pfs48/45 epitopes were detected by ELISA using synthetic peptides corresponding to B-cell epitopes previously described for MSP-3 and GLURP or identified by BepiPred for Pfs48/45. The results showed that the immunodominant epitopes were P11 from GLURP and MSP-3c and DG210 from MSP-3. The IgG1 and IgG3 subclasses were preferentially induced against these epitopes, supporting previous studies that these proteins are targets for cytophilic antibodies, important for the acquisition of protective immunity. Most individuals presented detectable IgG antibodies against Pfs48/45a and/or Pfs48/45b, validating the prediction of linear B-cell epitopes. The higher frequency and antibody levels against different epitopes from GLURP, MSP-3, and Pfs48/45 provide additional information that may suggest the relevance of GMZ2.6c as a multi-stage malaria vaccine candidate.
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8
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Zhang Y, Li D, Lu S, Zheng B. Toxoplasmosis vaccines: what we have and where to go? NPJ Vaccines 2022; 7:131. [PMID: 36310233 PMCID: PMC9618413 DOI: 10.1038/s41541-022-00563-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 10/17/2022] [Indexed: 11/16/2022] Open
Abstract
Despite recent major advances in developing effective vaccines against toxoplasmosis, finding new protective vaccination strategies remains a challenging and elusive goal as it is critical to prevent the disease. Over the past few years, various experimental approaches have shown that developing an effective vaccine against T. gondii is achievable. However, more remains unknown due to its complicated life cycle, difficulties in clinical translation, and lack of a standardized platform. This minireview summarizes the recent advances in the development of T. gondii vaccines and the main obstacles to developing a safe, effective and durable T. gondii vaccine. The successes and failures in developing and testing vaccine candidates for the T. gondii vaccine are also discussed, which may facilitate the future development of T. gondii vaccines.
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Affiliation(s)
- Yizhuo Zhang
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
| | - Dan Li
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
| | - Shaohong Lu
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Key Laboratory of Bio-tech Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
| | - Bin Zheng
- grid.506977.a0000 0004 1757 7957Institute of Parasitic Diseases, School of Basic Medicine and Forensics, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Engineering Research Center of Novel Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China ,grid.506977.a0000 0004 1757 7957Key Laboratory of Bio-tech Vaccine of Zhejiang Province, Hangzhou Medical College, Hangzhou, China
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9
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Coelho CH, Galson JD, Trück J, Duffy PE. B cell clonal expansion and mutation in the immunoglobulin heavy chain variable domain in response to Pfs230 and Pfs25 malaria vaccines. Int J Parasitol 2022; 52:707-710. [PMID: 34896314 PMCID: PMC9177897 DOI: 10.1016/j.ijpara.2021.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/29/2021] [Accepted: 11/03/2021] [Indexed: 12/26/2022]
Abstract
Malaria transmission-blocking vaccines induce antibodies that target Plasmodium in the mosquito vector. We recently reported that Pfs230 vaccine achieves activity superior to Pfs25 in humans. Here, we describe clonal expansion in the variable region of immunoglobulin heavy chains (VH) of antigen-specific single B cells collected from humans immunised with Pfs230D1-EPA or Pfs25-EPA conjugate vaccines formulated in Alhydrogel®. Based on studies of CD27+ memory B cells following Pfs230 vaccination, clonal expansion and somatic hypermutation was seen in four of five subjects. Pfs25 did not induce sufficient CD27+ cells for sorting; based instead on CD19+ Pfs25-reactive B cells, clonal expansion was only seen in two of five subjects. Clonal expansions and mutations in Pfs230-specific single B cells combined with the enhanced activity of Pfs230 antibodies by complement, might justify the outstanding activity of Pfs230D1 as a TBV candidate.
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Affiliation(s)
- Camila H Coelho
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Jacob D Galson
- Division of Immunology, University Children's Hospital Zurich and Clinical Research Center, University of Zurich, Switzerland; Alchemab Therapeutics Ltd, London, United Kingdom
| | - Johannes Trück
- Division of Immunology, University Children's Hospital Zurich and Clinical Research Center, University of Zurich, Switzerland
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA.
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10
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Chan JA, Loughland JR, de la Parte L, Okano S, Ssewanyana I, Nalubega M, Nankya F, Musinguzi K, Rek J, Arinaitwe E, Tipping P, Bourke P, Andrew D, Dooley N, SheelaNair A, Wines BD, Hogarth PM, Beeson JG, Greenhouse B, Dorsey G, Kamya M, Hartel G, Minigo G, Feeney M, Jagannathan P, Boyle MJ. Age-dependent changes in circulating Tfh cells influence development of functional malaria antibodies in children. Nat Commun 2022; 13:4159. [PMID: 35851033 PMCID: PMC9293980 DOI: 10.1038/s41467-022-31880-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 07/08/2022] [Indexed: 01/29/2023] Open
Abstract
T-follicular helper (Tfh) cells are key drivers of antibodies that protect from malaria. However, little is known regarding the host and parasite factors that influence Tfh and functional antibody development. Here, we use samples from a large cross-sectional study of children residing in an area of high malaria transmission in Uganda to characterize Tfh cells and functional antibodies to multiple parasites stages. We identify a dramatic re-distribution of the Tfh cell compartment with age that is independent of malaria exposure, with Th2-Tfh cells predominating in early childhood, while Th1-Tfh cell gradually increase to adult levels over the first decade of life. Functional antibody acquisition is age-dependent and hierarchical acquired based on parasite stage, with merozoite responses followed by sporozoite and gametocyte antibodies. Antibodies are boosted in children with current infection, and are higher in females. The children with the very highest antibody levels have increased Tfh cell activation and proliferation, consistent with a key role of Tfh cells in antibody development. Together, these data reveal a complex relationship between the circulating Tfh compartment, antibody development and protection from malaria.
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Affiliation(s)
- Jo-Anne Chan
- Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
| | - Jessica R Loughland
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia.,Global and Tropical Health Division, Menzies School of Health Research, Tiwi, Australia
| | | | - Satomi Okano
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Isaac Ssewanyana
- Infectious Diseases Research Collaboration, Kampala, Uganda.,London School of Hygiene and Tropical Medicine, London, UK
| | - Mayimuna Nalubega
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia.,Infectious Diseases Research Collaboration, Kampala, Uganda.,Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia
| | | | | | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Peta Tipping
- Global and Tropical Health Division, Menzies School of Health Research, Tiwi, Australia
| | - Peter Bourke
- Division of Medicine, Cairns Hospital, Manunda, QLD, Australia
| | - Dean Andrew
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Nicholas Dooley
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia.,Griffith University, Brisbane, QLD, Australia
| | - Arya SheelaNair
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Bruce D Wines
- Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Clinical Pathology, The University of Melbourne, Parkville, VIC, Australia
| | - P Mark Hogarth
- Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Department of Clinical Pathology, The University of Melbourne, Parkville, VIC, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia.,Department of Medicine, The University of Melbourne, Parkville, VIC, Australia.,Department of Microbiology, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | | | - Grant Dorsey
- University of California San Francisco, San Francisco, CA, USA
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Gunter Hartel
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Gabriela Minigo
- Global and Tropical Health Division, Menzies School of Health Research, Tiwi, Australia.,College of Health and Human Sciences, Charles Darwin University, Darwin, NT, Australia
| | - Margaret Feeney
- University of California San Francisco, San Francisco, CA, USA
| | | | - Michelle J Boyle
- Burnet Institute, Melbourne, VIC, Australia. .,QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia. .,Global and Tropical Health Division, Menzies School of Health Research, Tiwi, Australia. .,Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia. .,Griffith University, Brisbane, QLD, Australia.
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11
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Kurtovic L, Drew DR, Dent AE, Kazura JW, Beeson JG. Antibody Targets and Properties for Complement-Fixation Against the Circumsporozoite Protein in Malaria Immunity. Front Immunol 2021; 12:775659. [PMID: 34925347 PMCID: PMC8671933 DOI: 10.3389/fimmu.2021.775659] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/15/2021] [Indexed: 01/02/2023] Open
Abstract
The Plasmodium falciparum circumsporozoite protein (CSP) forms the basis of leading subunit malaria vaccine candidates. However, the mechanisms and specific targets of immunity are poorly defined. Recent findings suggest that antibody-mediated complement-fixation and activation play an important role in immunity. Here, we investigated the regions of CSP targeted by functional complement-fixing antibodies and the antibody properties associated with this activity. We quantified IgG, IgM, and functional complement-fixing antibody responses to different regions of CSP among Kenyan adults naturally exposed to malaria (n=102) and using a series of rabbit vaccination studies. Individuals who acquired functional complement-fixing antibodies had higher IgG, IgM and IgG1 and IgG3 to CSP. Acquired complement-fixing antibodies targeted the N-terminal, central-repeat, and C-terminal regions of CSP, and positive responders had greater antibody breadth compared to those who were negative for complement-fixing antibodies (p<0.05). Using rabbit vaccinations as a model, we confirmed that IgG specific to the central-repeat and non-repeat regions of CSP could effectively fix complement. However, vaccination with near full length CSP in rabbits poorly induced antibodies to the N-terminal region compared to naturally-acquired immunity in humans. Poor induction of N-terminal antibodies was also observed in a vaccination study performed in mice. IgG and IgM to all three regions of CSP play a role in mediating complement-fixation, which has important implications for malaria vaccine development.
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Affiliation(s)
- Liriye Kurtovic
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Damien R. Drew
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
| | - Arlene E. Dent
- Center for Global Health and Diseases, Case Western University, Cleveland, OH, United States
| | - James W. Kazura
- Center for Global Health and Diseases, Case Western University, Cleveland, OH, United States
| | - James G. Beeson
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
- Department of Microbiology, Monash University, Clayton, VIC, Australia
- Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
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12
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Opi DH, Kurtovic L, Chan JA, Horton JL, Feng G, Beeson JG. Multi-functional antibody profiling for malaria vaccine development and evaluation. Expert Rev Vaccines 2021; 20:1257-1272. [PMID: 34530671 DOI: 10.1080/14760584.2021.1981864] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION A vaccine would greatly accelerate current global efforts toward malaria elimination. While a partially efficacious vaccine has been achieved for Plasmodium falciparum, a major bottleneck in developing highly efficacious vaccines is a lack of reliable correlates of protection, and the limited application of assays that quantify functional immune responses to evaluate and down-select vaccine candidates in pre-clinical studies and clinical trials. AREAS COVERED In this review, we describe the important role of antibodies in immunity against malaria and detail the nature and functional activities of antibodies against the malaria-causing parasite. We highlight the growing understanding of antibody effector functions against malaria and in vitro assays to measure these functional antibody responses. We discuss the application of these assays to quantify antibody functions in vaccine development and evaluation. EXPERT OPINION It is becoming increasingly clear that multiple antibody effector functions are involved in immunity to malaria. Therefore, we propose that evaluating vaccine candidates needs to move beyond individual assays or measuring IgG magnitude alone. Instead, vaccine evaluation should incorporate the full breadth of antibody response types and harness a wider range of assays measuring functional antibody responses. We propose a 3-tier approach to implementing assays to inform vaccine evaluation.
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Affiliation(s)
- D Herbert Opi
- Life Sciences, Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia.,Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Liriye Kurtovic
- Life Sciences, Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Jo-Anne Chan
- Life Sciences, Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia.,Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Jessica L Horton
- Life Sciences, Burnet Institute, Melbourne, Australia.,Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Gaoqian Feng
- Life Sciences, Burnet Institute, Melbourne, Australia.,Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - James G Beeson
- Life Sciences, Burnet Institute, Melbourne, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, Australia.,Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, Australia.,Department of Microbiology, Monash University, Clayton, Australia
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13
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Rathnayake D, Aitken EH, Rogerson SJ. Beyond Binding: The Outcomes of Antibody-Dependent Complement Activation in Human Malaria. Front Immunol 2021; 12:683404. [PMID: 34168652 PMCID: PMC8217965 DOI: 10.3389/fimmu.2021.683404] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
Antibody immunity against malaria is effective but non-sterile. In addition to antibody-mediated inhibition, neutralisation or opsonisation of malaria parasites, antibody-mediated complement activation is also important in defense against infection. Antibodies form immune complexes with parasite-derived antigens that can activate the classical complement pathway. The complement system provides efficient surveillance for infection, and its activation leads to parasite lysis or parasite opsonisation for phagocytosis. The induction of complement-fixing antibodies contributes significantly to the development of protective immunity against clinical malaria. These complement-fixing antibodies can form immune complexes that are recognised by complement receptors on innate cells of the immune system. The efficient clearance of immune complexes is accompanied by complement receptor internalisation, abrogating the detrimental consequences of excess complement activation. Here, we review the mechanisms of activation of complement by alternative, classical, and lectin pathways in human malaria at different stages of the Plasmodium life cycle with special emphasis on how complement-fixing antibodies contribute to protective immunity. We briefly touch upon the action of anaphylatoxins, the assembly of membrane attack complex, and the possible reasons underlying the resistance of infected erythrocytes towards antibody-mediated complement lysis, relevant to their prolonged survival in the blood of the human host. We make suggestions for further research on effector functions of antibody-mediated complement activation that would guide future researchers in deploying complement-fixing antibodies in preventive or therapeutic strategies against malaria.
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Affiliation(s)
| | | | - Stephen J. Rogerson
- Department of Infectious Diseases, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
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14
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Soon MSF, Nalubega M, Boyle MJ. T-follicular helper cells in malaria infection and roles in antibody induction. OXFORD OPEN IMMUNOLOGY 2021; 2:iqab008. [PMID: 36845571 PMCID: PMC9914587 DOI: 10.1093/oxfimm/iqab008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 01/29/2023] Open
Abstract
Immunity to malaria is mediated by antibodies that block parasite replication to limit parasite burden and prevent disease. Cytophilic antibodies have been consistently shown to be associated with protection, and recent work has improved our understanding of the direct and Fc-mediated mechanisms of protective antibodies. Antibodies also have important roles in vaccine-mediated immunity. Antibody induction is driven by the specialized CD4+ T cells, T-follicular helper (Tfh) cells, which function within the germinal centre to drive B-cell activation and antibody induction. In humans, circulating Tfh cells can be identified in peripheral blood and are differentiated into subsets that appear to have pathogen/vaccination-specific roles in antibody induction. Tfh cell responses are essential for protective immunity from Plasmodium infection in murine models of malaria. Our understanding of the activation of Tfh cells during human malaria infection and the importance of different Tfh cell subsets in antibody development is still emerging. This review will discuss our current knowledge of Tfh cell activation and development in malaria, and the potential avenues and pitfalls of targeting Tfh cells to improve malaria vaccines.
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Affiliation(s)
- Megan S F Soon
- Department of Infectious Diseases, QIMR-Berghofer, 300 Herston Road, Herston, QLD, 4006, Australia
| | - Mayimuna Nalubega
- Infectious Diseases Research Collaboration, Tororo District Hospital, Tororo, Uganda
| | - Michelle J Boyle
- Department of Infectious Diseases, QIMR-Berghofer, 300 Herston Road, Herston, QLD, 4006, Australia,Correspondence address. QIMR Berghofer Medical Research Institute, Brisbane, Australia. E-mail:
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15
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Feng G, Wines BD, Kurtovic L, Chan JA, Boeuf P, Mollard V, Cozijnsen A, Drew DR, Center RJ, Marshall DL, Chishimba S, McFadden GI, Dent AE, Chelimo K, Boyle MJ, Kazura JW, Hogarth PM, Beeson JG. Mechanisms and targets of Fcγ-receptor mediated immunity to malaria sporozoites. Nat Commun 2021; 12:1742. [PMID: 33741975 PMCID: PMC7979888 DOI: 10.1038/s41467-021-21998-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 02/24/2021] [Indexed: 12/19/2022] Open
Abstract
A highly protective vaccine will greatly facilitate achieving and sustaining malaria elimination. Understanding mechanisms of antibody-mediated immunity is crucial for developing vaccines with high efficacy. Here, we identify key roles in humoral immunity for Fcγ-receptor (FcγR) interactions and opsonic phagocytosis of sporozoites. We identify a major role for neutrophils in mediating phagocytic clearance of sporozoites in peripheral blood, whereas monocytes contribute a minor role. Antibodies also promote natural killer cell activity. Mechanistically, antibody interactions with FcγRIII appear essential, with FcγRIIa also required for maximum activity. All regions of the circumsporozoite protein are targets of functional antibodies against sporozoites, and N-terminal antibodies have more activity in some assays. Functional antibodies are slowly acquired following natural exposure to malaria, being present among some exposed adults, but uncommon among children. Our findings reveal targets and mechanisms of immunity that could be exploited in vaccine design to maximize efficacy.
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Affiliation(s)
- Gaoqian Feng
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Department of Medicine and Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Bruce D Wines
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Clinical Pathology, The University of Melbourne, Melbourne, VIC, Australia
| | - Liriye Kurtovic
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Jo-Anne Chan
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Philippe Boeuf
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Department of Medicine and Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Vanessa Mollard
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Anton Cozijnsen
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Damien R Drew
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - Rob J Center
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Department of Medicine and Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Daniel L Marshall
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Sandra Chishimba
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Department of Medicine and Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Geoffrey I McFadden
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Arlene E Dent
- Centre for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Kiprotich Chelimo
- Department of Biomedical Science and Technology, Maseno University, Kisumu, Kenya
| | - Michelle J Boyle
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Department of Immunology, IMR-Berghofer Institute, Herston, QLD, Australia
| | - James W Kazura
- Centre for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - P Mark Hogarth
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
- Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Clinical Pathology, The University of Melbourne, Melbourne, VIC, Australia
| | - James G Beeson
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia.
- Department of Medicine and Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia.
- Central Clinical School, Monash University, Melbourne, VIC, Australia.
- Department of Microbiology, Monash University, Melbourne, VIC, Australia.
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16
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Abstract
Introduction: An effective vaccine against malaria forms a global health priority. Both naturally acquired immunity and sterile protection induced by irradiated sporozoite immunization were described decades ago. Still no vaccine exists that sufficiently protects children in endemic areas. Identifying immunological correlates of vaccine efficacy can inform rational vaccine design and potentially accelerate clinical development.Areas covered: We discuss recent research on immunological correlates of malaria vaccine efficacy, including: insights from state-of-the-art omics platforms and systems vaccinology analyses; functional anti-parasitic assays; pre-immunization predictors of vaccine efficacy; and comparison of correlates of vaccine efficacy against controlled human malaria infections (CHMI) and against naturally acquired infections.Expert Opinion: Effective vaccination may be achievable without necessarily understanding immunological correlates, but the relatively disappointing efficacy of malaria vaccine candidates in target populations is concerning. Hypothesis-generating omics and systems vaccinology analyses, alongside assessment of pre-immunization correlates, have the potential to bring about paradigm-shifts in malaria vaccinology. Functional assays may represent in vivo effector mechanisms, but have scarcely been formally assessed as correlates. Crucially, evidence is still meager that correlates of vaccine efficacy against CHMI correspond with those against naturally acquired infections in target populations. Finally, the diversity of immunological assays and efficacy endpoints across malaria vaccine trials remains a major confounder.
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Affiliation(s)
| | - Matthew B B McCall
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands.,Institut für Tropenmedizin, Universitätsklinikum Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
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17
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Liposome engraftment and antigen combination potentiate the immune response towards conserved epitopes of the malaria vaccine candidate MSP2. Vaccine 2021; 39:1746-1757. [PMID: 33618946 DOI: 10.1016/j.vaccine.2021.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/30/2021] [Accepted: 02/06/2021] [Indexed: 11/23/2022]
Abstract
Merozoite surface protein 2 (MSP2) is a highly abundant, GPI-anchored surface antigen on merozoites of the malaria parasite Plasmodium falciparum. It consists of highly conserved N- and C-terminal domains, and a central polymorphic region that allows all MSP2 alleles to be categorized into the 3D7 or FC27 family. Previously it has been shown that epitope accessibility differs between lipid-bound and lipid-free MSP2, suggesting that lipid interactions modulate the conformation and antigenicity in a way that may better mimic native MSP2 on the merozoite surface. Therefore, we have immunised mice with MSP2 engrafted onto liposomes using a C-terminal tether that mimics the native GPI anchor. To improve the immunogenicity of the formulated antigen, liposomes were supplemented with Pathogen Associated Molecular Pattern molecules, specifically agonists of the Toll-like receptor 4 (TLR4) or TLR2. Induced antibodies were directed mostly towards conserved epitopes, predominantly in the conserved C-terminal region of MSP2. We also found that immunisation with a combination of 3D7 and FC27 MSP2 enhanced antibody responses to conserved epitopes, and that the overall responses of mice immunised with MSP2-engrafted liposomes were comparable in magnitude to those of mice immunised with MSP2 formulated in Montanide ISA720. The antibodies elicited in mice by immunising with MSP2-engrafted liposomes recognised the native form of parasite MSP2 on western blots and were found to be cross-reactive with isolated 3D7 and FC27 merozoites when investigated by ELISA. The liposome-tethered MSP2 induced higher titres of complement-fixing antibodies to 3D7 and FC27 MSP2 than did MSP2 formulated in Montanide ISA720. Our results indicate that liposomal formulation represents a viable strategy for eliciting a strong immune response that favours conserved epitopes in MSP2 and thus a strain-transcendent immune response.
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18
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Ssewanyana I, Rek J, Rodriguez I, Wu L, Arinaitwe E, Nankabirwa JI, Beeson JG, Mayanja-Kizza H, Rosenthal PJ, Dorsey G, Kamya MR, Drakeley C, Greenhouse B, Tetteh KKA. Impact of a Rapid Decline in Malaria Transmission on Antimalarial IgG Subclasses and Avidity. Front Immunol 2021; 11:576663. [PMID: 33584643 PMCID: PMC7873448 DOI: 10.3389/fimmu.2020.576663] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/17/2020] [Indexed: 11/19/2022] Open
Abstract
Understanding how immunity to malaria is affected by declining transmission is important to aid vaccine design and understand disease resurgence. Both IgG subclasses and avidity of antigen-specific responses are important components of an effective immune response. Using a multiplex bead array assay, we measured the total IgG, IgG subclasses, and avidity profiles of responses to 18 P. falciparum blood stage antigens in samples from 160 Ugandans collected at two time points during high malaria transmission and two time points following a dramatic reduction in transmission. Results demonstrated that, for the antigens tested, (i) the rate of decay of total IgG following infection declined with age and was driven consistently by the decrease in IgG3 and occasionally the decrease in IgG1; (ii) the proportion of IgG3 relative to IgG1 in the absence of infection increased with age; (iii) the increase in avidity index (the strength of association between the antibody and antigen) following infection was largely due to a rapid loss of non-avid compared to avid total IgG; and (iv) both avid and non-avid total IgG in the absence of infection increased with age. Further studies are required to understand the functional differences between IgG1 and IgG3 in order to determine their contribution to the longevity of protective immunity to malaria. Measuring changes in antibody avidity may be a better approach of detecting affinity maturation compared to avidity index due to the differential expansion and contraction of high and low avidity total IgG.
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Affiliation(s)
- Isaac Ssewanyana
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Isabel Rodriguez
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Lindsey Wu
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emmanuel Arinaitwe
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University, Kampala, Uganda
| | - 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
| | | | - Philip J Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University, Kampala, Uganda
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States.,Chan Zuckerberg Biohub, San Francisco, CA, United States
| | - Kevin K A Tetteh
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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19
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Th2-like T Follicular Helper Cells Promote Functional Antibody Production during Plasmodium falciparum Infection. CELL REPORTS MEDICINE 2020; 1:100157. [PMID: 33377128 PMCID: PMC7762767 DOI: 10.1016/j.xcrm.2020.100157] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/08/2020] [Accepted: 11/19/2020] [Indexed: 01/10/2023]
Abstract
CD4+ T follicular helper cells (Tfh) are key drivers of antibody development. During Plasmodium falciparum malaria in children, the activation of Tfh is restricted to the Th1 subset and not associated with antibody levels. To identify Tfh subsets that are associated with antibody development in malaria, we assess Tfh and antibodies longitudinally in human volunteers with experimental P. falciparum infection. Tfh cells activate during infection, with distinct dynamics in different Tfh subsets. Th2-Tfh cells activate early, during peak infection, while Th1-Tfh cells activate 1 week after peak infection and treatment. Th2-Tfh cell activation is associated with the functional breadth and magnitude of parasite antibodies. In contrast, Th1-Tfh activation is not associated with antibody development but instead with plasma cells, which have previously been shown to play a detrimental role in the development of long-lived immunity. Thus, our study identifies the contrasting roles of Th2 and Th1-Tfh cells during experimental P. falciparum malaria.
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20
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Subdominance in Antibody Responses: Implications for Vaccine Development. Microbiol Mol Biol Rev 2020; 85:85/1/e00078-20. [PMID: 33239435 DOI: 10.1128/mmbr.00078-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Vaccines work primarily by eliciting antibodies, even when recovery from natural infection depends on cellular immunity. Large efforts have therefore been made to identify microbial antigens that elicit protective antibodies, but these endeavors have encountered major difficulties, as witnessed by the lack of vaccines against many pathogens. This review summarizes accumulating evidence that subdominant protein regions, i.e., surface-exposed regions that elicit relatively weak antibody responses, are of particular interest for vaccine development. This concept may seem counterintuitive, but subdominance may represent an immune evasion mechanism, implying that the corresponding region potentially is a key target for protective immunity. Following a presentation of the concepts of immunodominance and subdominance, the review will present work on subdominant regions in several major human pathogens: the protozoan Plasmodium falciparum, two species of pathogenic streptococci, and the dengue and influenza viruses. Later sections are devoted to the molecular basis of subdominance, its potential role in immune evasion, and general implications for vaccine development. Special emphasis will be placed on the fact that a whole surface-exposed protein domain can be subdominant, as demonstrated for all of the pathogens described here. Overall, the available data indicate that subdominant protein regions are of much interest for vaccine development, not least in bacterial and protozoal systems, for which antibody subdominance remains largely unexplored.
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21
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Kiyuka PK, Meri S, Khattab A. Complement in malaria: immune evasion strategies and role in protective immunity. FEBS Lett 2020; 594:2502-2517. [PMID: 32181490 PMCID: PMC8653895 DOI: 10.1002/1873-3468.13772] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/03/2020] [Accepted: 03/03/2020] [Indexed: 12/12/2022]
Abstract
The malaria parasite has for long been thought to escape host complement attack as a survival strategy. However, it was only recently that complement evasion mechanisms of the parasite were described. Simultaneously, the role of complement in antibody-mediated naturally acquired and vaccine-induced protection against malaria has also been reported. Such findings should be considered in future vaccine design, given the current need to develop more efficacious vaccines against malaria. Parasite antigens derived from molecules mediating functions crucial for parasite survival, such as complement evasion, or parasite antigens against which antibody responses lead to an efficient complement attack could present new candidates for vaccines. In this review, we discuss recent findings on complement evasion by the malaria parasites and the emerging role of complement in antibody-mediated protection against malaria. We emphasize that immune responses to vaccines based on complement inhibitors should not only induce complement-activating antibodies but also neutralize the escape mechanisms of the parasite.
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Affiliation(s)
- Patience Kerubo Kiyuka
- Department of Bacteriology and Immunology, Translational Immunology Research Program, Haartman Institute, University of Helsinki, Finland
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Seppo Meri
- Department of Bacteriology and Immunology, Translational Immunology Research Program, Haartman Institute, University of Helsinki, Finland
- Helsinki University Central Hospital, Finland
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
| | - Ayman Khattab
- Department of Bacteriology and Immunology, Translational Immunology Research Program, Haartman Institute, University of Helsinki, Finland
- Department of Nucleic Acid Research, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, Alexandria, Egypt
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22
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Aitken EH, Mahanty S, Rogerson SJ. Antibody effector functions in malaria and other parasitic diseases: a few needles and many haystacks. Immunol Cell Biol 2020; 98:264-275. [DOI: 10.1111/imcb.12320] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/02/2020] [Accepted: 01/28/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Elizabeth H Aitken
- Department of Medicine The Doherty Institute The University of Melbourne 792 Elizabeth Street Melbourne VIC 3000 Australia
| | - Siddhartha Mahanty
- Department of Medicine The Doherty Institute The University of Melbourne 792 Elizabeth Street Melbourne VIC 3000 Australia
| | - Stephen J Rogerson
- Department of Medicine The Doherty Institute The University of Melbourne 792 Elizabeth Street Melbourne VIC 3000 Australia
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23
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Immunization with full-length Plasmodium falciparum merozoite surface protein 1 is safe and elicits functional cytophilic antibodies in a randomized first-in-human trial. NPJ Vaccines 2020; 5:10. [PMID: 32025341 PMCID: PMC6994672 DOI: 10.1038/s41541-020-0160-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/14/2020] [Indexed: 12/20/2022] Open
Abstract
A vaccine remains a priority in the global fight against malaria. Here, we report on a single-center, randomized, double-blind, placebo and adjuvant-controlled, dose escalation phase 1a safety and immunogenicity clinical trial of full-length Plasmodium falciparum merozoite surface protein 1 (MSP1) in combination with GLA-SE adjuvant. Thirty-two healthy volunteers were vaccinated at least three times with MSP1 plus adjuvant, adjuvant alone, or placebo (24:4:4) to evaluate the safety and immunogenicity. MSP1 was safe, well tolerated and immunogenic, with all vaccinees sero-converting independent of the dose. The MSP1-specific IgG and IgM titers persisted above levels found in malaria semi-immune humans for at least 6 months after the last immunization. The antibodies were variant- and strain-transcending and stimulated respiratory activity in granulocytes. Furthermore, full-length MSP1 induced memory T-cells. Our findings encourage challenge studies as the next step to evaluate the efficacy of full-length MSP1 as a vaccine candidate against falciparum malaria (EudraCT 2016-002463-33).
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24
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Kurtovic L, Boyle MJ, Opi DH, Kennedy AT, Tham WH, Reiling L, Chan JA, Beeson JG. Complement in malaria immunity and vaccines. Immunol Rev 2019; 293:38-56. [PMID: 31556468 PMCID: PMC6972673 DOI: 10.1111/imr.12802] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/03/2019] [Indexed: 12/20/2022]
Abstract
Developing efficacious vaccines for human malaria caused by Plasmodium falciparum is a major global health priority, although this has proven to be immensely challenging over the decades. One major hindrance is the incomplete understanding of specific immune responses that confer protection against disease and/or infection. While antibodies to play a crucial role in malaria immunity, the functional mechanisms of these antibodies remain unclear as most research has primarily focused on the direct inhibitory or neutralizing activity of antibodies. Recently, there is a growing body of evidence that antibodies can also mediate effector functions through activating the complement system against multiple developmental stages of the parasite life cycle. These antibody‐complement interactions can have detrimental consequences to parasite function and viability, and have been significantly associated with protection against clinical malaria in naturally acquired immunity, and emerging findings suggest these mechanisms could contribute to vaccine‐induced immunity. In order to develop highly efficacious vaccines, strategies are needed that prioritize the induction of antibodies with enhanced functional activity, including the ability to activate complement. Here we review the role of complement in acquired immunity to malaria, and provide insights into how this knowledge could be used to harness complement in malaria vaccine development.
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Affiliation(s)
- Liriye Kurtovic
- Burnet Institute, Melbourne, Vic., Australia.,Central Clinical School, Monash University, Melbourne, Vic., Australia
| | | | | | - Alexander T Kennedy
- Walter and Eliza Hall Institute, Melbourne, Vic., Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Vic., Australia
| | - Wai-Hong Tham
- Walter and Eliza Hall Institute, Melbourne, Vic., Australia
| | | | - Jo-Anne Chan
- Burnet Institute, Melbourne, Vic., Australia.,Central Clinical School, Monash University, Melbourne, Vic., Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Vic., Australia.,Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Microbiology, Monash University, Clayton, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
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25
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Characterization of drug resistance and genetic diversity of Plasmodium falciparum parasites from Tripura, Northeast India. Sci Rep 2019; 9:13704. [PMID: 31548652 PMCID: PMC6757058 DOI: 10.1038/s41598-019-50152-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 09/06/2019] [Indexed: 01/23/2023] Open
Abstract
Monitoring of anti-malarial drug resistance is vital in Northeast India as this region shares its international border with Southeast Asia. Genetic diversity of Plasmodium parasites regulates transmission dynamics, disease severity and vaccine efficacy. P. falciparum chloroquine resistance transporter (Pfcrt), multidrug resistance-1 (Pfmdr-1) and kelch 13 propeller (PfK-13) genes which govern antimalarial drug resistance and three genetic diversity markers, merozoite surface protein 1 and 2 (Pfmsp-1, Pfmsp-2) and glutamate rich protein (Pfglurp) were evaluated from Tripura, Northeast India using molecular tools. In the Pfcrt gene, 87% isolates showed triple mutations at codons M74I, N75E and K76T. 12.5% isolates in Pfmdr-1 gene showed mutation at N86Y. No polymorphism in PfK-13 propeller was found. Polyclonal infections were observed in 53.85% isolates and more commonly in adults (p = 0.0494). In the Pfmsp-1 locus, the K1 allelic family was predominant (71.2%) followed by the 3D7/IC family (69.2%) in the Pfmsp-2 locus. RII region of Pfglurp exhibited nine alleles with expected heterozygosity of 0.85. The multiplicity of infection for Pfmsp-1, Pfmsp-2 and Pfglurp were 1.56, 1.31 and 1.06 respectively. Overall, the study demonstrated a high level of chloroquine resistance and extensive parasite diversity in the region, necessitating regular surveillance in this population group.
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26
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Eacret JS, Gonzales DM, Franks RG, Burns JM. Immunization with merozoite surface protein 2 fused to a Plasmodium-specific carrier protein elicits strain-specific and strain-transcending, opsonizing antibody. Sci Rep 2019; 9:9022. [PMID: 31227760 PMCID: PMC6588637 DOI: 10.1038/s41598-019-45440-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 06/06/2019] [Indexed: 11/21/2022] Open
Abstract
Vaccine trials and cohort studies in Plasmodium falciparum endemic areas indicate that naturally-acquired and vaccine-induced antibodies to merozoite surface protein 2 (MSP2) are associated with resistance to malaria. These data indicate that PfMSP2 has significant potential as a component of a multi-antigen malaria vaccine. To overcome challenges encountered with subunit malaria vaccines, we established that the use of highly immunogenic rPfMSP8 as a carrier protein for leading vaccine candidates rPfMSP119 and rPfs25 facilitated antigen production, minimized antigenic competition and enhanced induction of functional antibodies. We applied this strategy to optimize a rPfMSP2 (3D7)-based subunit vaccine by producing unfused rPfMSP2 or chimeric rPfMSP2/8 in Escherichia coli. rPfMSP2 formed fibrils, which induced splenocyte proliferation in an antigen receptor-independent, TLR2-dependent manner. However, fusion to rPfMSP8 prevented rPfMSP2 amyloid-like fibril formation. Immunization of rabbits elicited high-titer anti-PfMSP2 antibodies that recognized rPfMSP2 of the 3D7 and FC27 alleles, as well as native PfMSP2. Competition assays revealed a difference in the specificity of antibodies induced by the two rPfMSP2-based vaccines, with evidence of epitope masking by rPfMSP2-associated fibrils. Rabbit anti-PfMSP2/8 was superior to rPfMSP2-elicited antibody at opsonizing P. falciparum merozoites for phagocytosis. These data establish rPfMSP8 as an effective carrier for a PfMSP2-based subunit malaria vaccine.
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Affiliation(s)
- Jacqueline S Eacret
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Donna M Gonzales
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - Raymond G Franks
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA
| | - James M Burns
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA, 19129, USA.
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27
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Moormann AM, Nixon CE, Forconi CS. Immune effector mechanisms in malaria: An update focusing on human immunity. Parasite Immunol 2019; 41:e12628. [PMID: 30972776 DOI: 10.1111/pim.12628] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 04/02/2019] [Accepted: 04/08/2019] [Indexed: 12/12/2022]
Abstract
The past decade has witnessed dramatic decreases in malaria-associated mortality and morbidity around the world. This progress has largely been due to intensified malaria control measures, implementation of rapid diagnostics and establishing a network to anticipate and mitigate antimalarial drug resistance. However, the ultimate tool for malaria prevention is the development and implementation of an effective vaccine. To date, malaria vaccine efforts have focused on determining which of the thousands of antigens expressed by Plasmodium falciparum are instrumental targets of protective immunity. The antigenic variation and antigenic polymorphisms arising in parasite genes under immune selection present a daunting challenge for target antigen selection and prioritization, and is a given caveat when interpreting immune recall responses or results from monovalent vaccine trials. Other immune evasion strategies executed by the parasite highlight the myriad of ways in which it can become a recurrent infection. This review provides an update on immune effector mechanisms in malaria and focuses on our improved ability to interrogate the complexity of human immune system, accelerated by recent methodological advances. Appreciating how the human immune landscape influences the effectiveness and longevity of antimalarial immunity will help explain which conditions are necessary for immune effector mechanisms to prevail.
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Affiliation(s)
- Ann M Moormann
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Christina E Nixon
- Department of Pathology and Lab Medicine, Brown University, Providence, Rhode Island
| | - Catherine S Forconi
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
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28
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Targets of complement-fixing antibodies in protective immunity against malaria in children. Nat Commun 2019; 10:610. [PMID: 30723225 PMCID: PMC6363798 DOI: 10.1038/s41467-019-08528-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/07/2019] [Indexed: 12/31/2022] Open
Abstract
Antibodies against P. falciparum merozoites fix complement to inhibit blood-stage replication in naturally-acquired and vaccine-induced immunity; however, specific targets of these functional antibodies and their importance in protective immunity are unknown. Among malaria-exposed individuals, we show that complement-fixing antibodies to merozoites are more strongly correlated with protective immunity than antibodies that inhibit growth quantified using the current reference assay for merozoite vaccine evaluation. We identify merozoite targets of complement-fixing antibodies and identify antigen-specific complement-fixing antibodies that are strongly associated with protection from malaria in a longitudinal study of children. Using statistical modelling, combining three different antigens targeted by complement-fixing antibodies could increase the potential protective effect to over 95%, and we identify antigens that were common in the most protective combinations. Our findings support antibody-complement interactions against merozoite antigens as important anti-malaria immune mechanisms, and identify specific merozoite antigens for further evaluation as vaccine candidates. Antibodies against Plasmodium falciparum merozoites that fix complement can inhibit blood-stage replication. Here, Reiling et al. show that complement-fixing antibodies strongly correlate with protective immunity in children, identify the merozoite targets, and predict antigen combinations that should result in strong protection.
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29
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Beeson JG, Kurtovic L, Dobaño C, Opi DH, Chan JA, Feng G, Good MF, Reiling L, Boyle MJ. Challenges and strategies for developing efficacious and long-lasting malaria vaccines. Sci Transl Med 2019; 11:11/474/eaau1458. [DOI: 10.1126/scitranslmed.aau1458] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/05/2018] [Accepted: 11/02/2018] [Indexed: 12/24/2022]
Abstract
Although there has been major recent progress in malaria vaccine development, substantial challenges remain for achieving highly efficacious and durable vaccines against Plasmodium falciparum and Plasmodium vivax malaria. Greater knowledge of mechanisms and key targets of immunity are needed to accomplish this goal, together with new strategies for generating potent, long-lasting, functional immunity against multiple antigens. Implementation considerations in endemic areas will ultimately affect vaccine effectiveness, so innovations to simplify and enhance delivery are also needed. Whereas challenges remain, recent exciting progress and emerging knowledge promise hope for the future of malaria vaccines.
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30
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Oyong DA, Kenangalem E, Poespoprodjo JR, Beeson JG, Anstey NM, Price RN, Boyle MJ. Loss of complement regulatory proteins on uninfected erythrocytes in vivax and falciparum malaria anemia. JCI Insight 2018; 3:124854. [PMID: 30429373 PMCID: PMC6303009 DOI: 10.1172/jci.insight.124854] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 10/16/2018] [Indexed: 01/12/2023] Open
Abstract
Anemia is a major complication of malaria, driven largely by loss of uninfected RBCs during infection. RBC clearance through loss of complement regulatory proteins (CRPs) is a significant contributor to anemia in Plasmodium falciparum infection, but its role in Plasmodium vivax infection is unknown. CRP loss increases RBC susceptibility to macrophage clearance, a process that is also regulated by CD47. We compared CRPs and CD47 expression on infected and uninfected RBCs in adult patients with vivax and falciparum malaria and different anemia severities from Papua, Indonesia. Complement activation and parasite-specific complement-fixing antibodies were measured by ELISA. Levels of CR1 and CD55 were reduced in severe anemia in both falciparum and vivax malaria. Loss of CRPs and CD47 was restricted to uninfected RBCs, with infected RBCs having higher expression. There was no association among complement-fixing antibodies, complement activation, and CRP loss. Our findings demonstrate that CRP loss is a pan-species, age-independent mechanism of malarial anemia. Higher levels of CRP and CD47 expression on infected RBCs suggest that parasites are protected from complement-mediated destruction and macrophage clearance. Lack of associations between protective antibodies and CRP loss highlight that complement pathogenic and protective pathways are distinct mechanisms during infection.
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Affiliation(s)
- Damian A. Oyong
- Menzies School of Health Research and,Charles Darwin University, Darwin, North Territory, Australia
| | - Enny Kenangalem
- Mimika District Health Authority and,Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | - Jeanne R. Poespoprodjo
- Mimika District Health Authority and,Papuan Health and Community Development Foundation, Timika, Papua, Indonesia.,Department of Paediatrics, Faculty of Medicine, Gadjah Mada University, Yogyakarta, Central Java, Indonesia
| | - James G. Beeson
- Burnet Institute, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia.,Department of Microbiology and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | | | - Ric N. Price
- Menzies School of Health Research and,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Michelle J. Boyle
- Menzies School of Health Research and,Burnet Institute, Melbourne, Victoria, Australia
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