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Kusi KA, Amoah LE, Acquah FK, Ennuson NA, Frempong AF, Ofori EA, Akyea-Mensah K, Kyei-Baafour E, Osei F, Frimpong A, Singh SK, Theisen M, Remarque EJ, Faber BW, Belmonte M, Ganeshan H, Huang J, Villasante E, Sedegah M. Plasmodium falciparum AMA1 and CSP antigen diversity in parasite isolates from southern Ghana. Front Cell Infect Microbiol 2024; 14:1375249. [PMID: 38808064 PMCID: PMC11132687 DOI: 10.3389/fcimb.2024.1375249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/19/2024] [Indexed: 05/30/2024] Open
Abstract
Introduction Diversity in malarial antigens is an immune evasion mechanism that gives malaria parasites an edge over the host. Immune responses against one variant of a polymorphic antigen are usually not fully effective against other variants due to altered epitopes. This study aimed to evaluate diversity in the Plasmodium falciparum antigens apical membrane antigen 1 (PfAMA1) and circumsporozoite protein (PfCSP) from circulating parasites in a malaria-endemic community in southern Ghana and to determine the effects of polymorphisms on antibody response specificity. Methods The study involved 300 subjects, whose P. falciparum infection status was determined by microscopy and PCR. Diversity within the two antigens was evaluated by msp2 gene typing and molecular gene sequencing, while the host plasma levels of antibodies against PfAMA1, PfCSP, and two synthetic 24mer peptides from the conserved central repeat region of PfCSP, were measured by ELISA. Results Of the 300 subjects, 171 (57%) had P. falciparum infection, with 165 of the 171 (96.5%) being positive for either or both of the msp2 allelic families. Gene sequencing of DNA from 55 clonally infected samples identified a total of 56 non-synonymous single nucleotide polymorphisms (SNPs) for the Pfama1 gene and these resulted in 44 polymorphic positions, including two novel positions (363 and 365). Sequencing of the Pfcsp gene from 69 clonal DNA samples identified 50 non-synonymous SNPs that resulted in 42 polymorphic positions, with half (21) of these polymorphic positions being novel. Of the measured antibodies, only anti-PfCSP antibodies varied considerably between PCR parasite-positive and parasite-negative persons. Discussion These data confirm the presence of a considerable amount of unique, previously unreported amino acid changes, especially within PfCSP. Drivers for this diversity in the Pfcsp gene do not immediately seem apparent, as immune pressure will be expected to drive a similar level of diversity in the Pfama1 gene.
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Affiliation(s)
- Kwadwo A. Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Linda E. Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Festus Kojo Acquah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Nana Aba Ennuson
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Abena F. Frempong
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Ebenezer A. Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Kwadwo Akyea-Mensah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Eric Kyei-Baafour
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Frank Osei
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Augustina Frimpong
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Susheel K. Singh
- Center for Medical Parasitology at the Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Congenital Diseases, Statens Serum Institut, Copenhagen, Denmark
| | - Michael Theisen
- Center for Medical Parasitology at the Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Congenital Diseases, Statens Serum Institut, Copenhagen, Denmark
| | - Edmond J. Remarque
- Department of Parasitology, Biomedical Primate Research Center, Rijswijk, Netherlands
| | - Bart W. Faber
- Department of Parasitology, Biomedical Primate Research Center, Rijswijk, Netherlands
| | - Maria Belmonte
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Harini Ganeshan
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Jun Huang
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Eileen Villasante
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
| | - Martha Sedegah
- Malaria Department, Naval Medical Research Command, Silver Spring, MD, United States
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Faber BW, Yeoh LM, Kurtovic L, Mol WEM, Poelert M, Smits E, Rodriguez Garcia R, Mandalawi-Van der Eijk M, van der Werff N, Voorberg-van der Wel A, Remarque EJ, Beeson JG, Kocken CHM. A Diversity Covering (DiCo) Plasmodium vivax apical membrane antigen-1 vaccine adjuvanted with RFASE/RSL10 yields high levels of growth-inhibitory antibodies. Vaccine 2024; 42:1785-1792. [PMID: 38365484 DOI: 10.1016/j.vaccine.2024.02.029] [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: 07/11/2023] [Revised: 01/10/2024] [Accepted: 02/07/2024] [Indexed: 02/18/2024]
Abstract
Plasmodium vivax malaria is increasingly recognized as a major global health problem and the socio-economic impact of P.vivax-induced burden is huge. Vaccine development against P. vivax malaria has been hampered by the lack of an in vitro culture system and poor access to P. vivax sporozoites. The recent generation of Plasmodium falciparum parasites that express a functional P. vivax AMA1 molecule has provided a platform for in vitro evaluation of PvAMA1 as a potential blood stage vaccine. Three so-called PvAMA1 Diversity Covering (DiCo) proteins were designed to assess their potential to induce a functional and broad humoral immune response to the polymorphic PvAMA1 molecule. Rabbits were immunized with the mixture of three, Pichia-produced, PvAMA1 DiCo proteins, as well as with 2 naturally occurring PvAMA1 alleles. For these three groups, the experimental adjuvant raffinose fatty acid sulfate ester (RFASE) was used, while in a fourth group the purified main mono-esterified constituent (RSL10) of this adjuvant was used. Animals immunized with the mixture of the three PvAMA1 DiCo proteins in RFASE showed high anti-PvAMA1 antibody titers against three naturally occurring PvAMA1variants while also high growth-inhibitory capacity was observed against P. falciparum parasites expressing PvAMA1. This supports further clinical development of the PvAMA1 DiCo mixture as a potential malaria vaccine. However, as the single allele PvAMA1 SalI-group showed similar characteristics in antibody titer and inhibition levels as the PvAMA1 DiCo mixture-group, this raises the question whether a mixture is really necessary to overcome the polymorphism in the vaccine candidate. RFASE induced strong humoral responses, as did the animals immunized with the purified component, RSL10. This suggests that RSL10 is the active ingredient. However, one of the RSL10-immunized animal showed a delayed response, necessitating further research into the clinical development of RSL10.
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Affiliation(s)
- Bart W Faber
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, the Netherlands.
| | - Lee M Yeoh
- Burnet Institute, Melbourne, Victoria, Australia; Department of Medicine, The University of Melbourne, Victoria, Australia
| | - Liriye Kurtovic
- Burnet Institute, Melbourne, Victoria, Australia; Central Clinical School and Department of Microbiology, Monash University, Victoria, Australia
| | | | | | | | | | | | - Nicole van der Werff
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, the Netherlands
| | | | - Edmond J Remarque
- Department of Virology, Biomedical Primate Research Centre, Rijswijk, the Netherlands
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, Australia; Central Clinical School and Department of Microbiology, Monash University, Victoria, Australia; Department of Infectious Diseases, University of Melbourne, Victoria, Australia
| | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, the Netherlands
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Patel PN, Dickey TH, Diouf A, Salinas ND, McAleese H, Ouahes T, Long CA, Miura K, Lambert LE, Tolia NH. Structure-based design of a strain transcending AMA1-RON2L malaria vaccine. Nat Commun 2023; 14:5345. [PMID: 37660103 PMCID: PMC10475129 DOI: 10.1038/s41467-023-40878-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/14/2023] [Indexed: 09/04/2023] Open
Abstract
Apical membrane antigen 1 (AMA1) is a key malaria vaccine candidate and target of neutralizing antibodies. AMA1 binds to a loop in rhoptry neck protein 2 (RON2L) to form the moving junction during parasite invasion of host cells, and this complex is conserved among apicomplexan parasites. AMA1-RON2L complex immunization achieves higher growth inhibitory activity than AMA1 alone and protects mice against Plasmodium yoelii challenge. Here, three single-component AMA1-RON2L immunogens were designed that retain the structure of the two-component AMA1-RON2L complex: one structure-based design (SBD1) and two insertion fusions. All immunogens elicited high antibody titers with potent growth inhibitory activity, yet these antibodies did not block RON2L binding to AMA1. The SBD1 immunogen induced significantly more potent strain-transcending neutralizing antibody responses against diverse strains of Plasmodium falciparum than AMA1 or AMA1-RON2L complex vaccination. This indicates that SBD1 directs neutralizing antibody responses to strain-transcending epitopes in AMA1 that are independent of RON2L binding. This work underscores the importance of neutralization mechanisms that are distinct from RON2 blockade. The stable single-component SBD1 immunogen elicits potent strain-transcending protection that may drive the development of next-generation vaccines for improved malaria and apicomplexan parasite control.
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Affiliation(s)
- Palak N Patel
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thayne H Dickey
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Nichole D Salinas
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Holly McAleese
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tarik Ouahes
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Lynn E Lambert
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj H Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Younis S, Faber BW, Kocken CHM, Remarque EJ. Identification of adjuvants for clinical trials performed with Plasmodium falciparum AMA1 in rabbits. BMC Immunol 2019; 20:25. [PMID: 31362695 PMCID: PMC6664700 DOI: 10.1186/s12865-019-0307-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 07/18/2019] [Indexed: 11/20/2022] Open
Abstract
Background In this study, seven adjuvants were compared for use with Plasmodium falciparum DiCo-Apical Membrane Antigen 1 (Pf-DiCo-AMA1), with the aim to identify an ideal adjuvant which yields high antibody titres and potentially broadens the responses in clinical trials. The following adjuvant formulations were evaluated: SE, SE-GLA, Liposomes, Liposomes-GLA, CoVaccine HT™, ImSaVac-P and ImSaVac-P o/w. The study was performed in rabbits, which were immunized with FVO-AMA1 in combination with one of the seven adjuvants. Antibody levels (humoral responses) and functional activity of the antibodies induced against malaria vaccine candidate AMA1 were evaluated. Thus, in this study the ideal adjuvant is expected to induce high functional antibody levels, a long-lived response, and a broad cross-strain activity. Results AMA1 formulated in all adjuvants was immunogenic. However, the magnitude of the immune responses differed between the seven adjuvants. The highest IgG levels were observed for the CoVaccine HT™ group, this was statistically significant for all four AMA1 variants versus all other adjuvant groups. No differences were observed in the breadth of the humoral response, i.e., increased recognition of AMA1 variants. Also, Growth Inhibition Activity (GIA) for both Plasmodium falciparum strains (FCR3 – homologous to FVO AMA1 protein and NF54 – heterologous to FVO AMA1 protein) were significantly higher in the CoVaccine HT™ group as compared to the other adjuvant groups. Conclusions In brief, all seven vaccine – adjuvant formulations were immunogenic. The magnitude of the immune responses differed between the seven adjuvants. No statistically significant differences were observed in the breadth of the humoral response, nor in longevity of the response. Nevertheless, AMA1 formulated in CoVaccine HT™ appeared as the best adjuvant for use in clinical trials. Electronic supplementary material The online version of this article (10.1186/s12865-019-0307-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sumera Younis
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Bart W Faber
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Clemens H M Kocken
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Edmond J Remarque
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands.
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Cawlfield A, Genito CJ, Beck Z, Bergmann-Leitner ES, Bitzer AA, Soto K, Zou X, Hadiwidjojo SH, Gerbasi RV, Mullins AB, Noe A, Waters NC, Alving CR, Matyas GR, Dutta S. Safety, toxicity and immunogenicity of a malaria vaccine based on the circumsporozoite protein (FMP013) with the adjuvant army liposome formulation containing QS21 (ALFQ). Vaccine 2019; 37:3793-3803. [PMID: 31151801 DOI: 10.1016/j.vaccine.2019.05.059] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 05/16/2019] [Accepted: 05/20/2019] [Indexed: 01/21/2023]
Abstract
Antibodies to Circumsporozoite protein (CSP) confer protection against controlled human malaria infection (CHMI) caused by the parasite Plasmodium falciparum. Although CSP is highly immunogenic, it does not induce long lasting protection and efforts to improve CSP-specific immunological memory and duration of protection are underway. We have previously reported that the clinical grade CSP vaccine FMP013 was immunogenic and protective against malaria challenge in mice when combined with the Army Liposomal Formulation adjuvant containing immune modulators 3D-PHAD™ and QS21 (ALFQ). To move forward with clinical evaluation, we now report the safety, toxicity and immunogenicity of clinical grade FMP013 and ALFQ in Rhesus macaques. Three groups of Rhesus (n = 6) received half or full human dose of FMP013 + ALFQ on a 0-1-2 month schedule, which showed mild local site reactions with no hematologic derangements in red blood cell homeostasis, liver function or kidney function. Immunization induced a transient systemic inflammatory response, including elevated white blood cell counts, mild fever, and a few incidences of elevated creatine kinase, receding to normal range by day 7 post vaccination. Optimal immunogenicity in Rhesus was observed using a 1 mL ALFQ + 20 µg FMP013 dose. Doubling the FMP013 antigen dose to 40 µg had no effect while halving the ALFQ adjuvant dose to 0.5 mL lowered immunogenicity. Similar to data generated in mice, FMP013 + ALFQ induced serum antibodies that reacted to all regions of the CSP molecule and a Th1-biased cytokine response in Rhesus. Rhesus antibody response to FMP013 + ALFQ was found to be non-inferior to historical benchmarks including that of RTS,S + AS01 in humans. A four-dose GLP toxicity study in rabbits confirmed no local site reactions and transient systemic inflammation associated with ALFQ adjuvant administration. These safety and immunogenicity data support the clinical progression and testing of FMP013 + ALFQ in a CHMI trial in the near future.
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Affiliation(s)
- Alicia Cawlfield
- Department of Veterinary Medicine, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Christopher J Genito
- Structural Vaccinology Laboratory, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Zoltan Beck
- Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817, USA
| | - Elke S Bergmann-Leitner
- Flow-cytometeric Center, Malaria Vaccine Branch, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Alexis A Bitzer
- Structural Vaccinology Laboratory, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Kimberly Soto
- Structural Vaccinology Laboratory, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Xiaoyan Zou
- Malaria Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Sri H Hadiwidjojo
- Malaria Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Robert V Gerbasi
- Malaria Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Anna B Mullins
- Department of Veterinary Medicine, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Amy Noe
- Leidos Life Sciences, 5202 Presidents Court, Suite 110, Fredrick, MD 21703, USA
| | - Norman C Waters
- Malaria Vaccine Branch, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Carl R Alving
- Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Gary R Matyas
- Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Sheetij Dutta
- Structural Vaccinology Laboratory, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA.
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Kusi KA, Faber BW, Koopman G, Remarque EJ. EDiP: the Epitope Dilution Phenomenon. Lessons learnt from a malaria vaccine antigen and its applicability to polymorphic antigens. Expert Rev Vaccines 2017; 17:13-21. [PMID: 29224404 DOI: 10.1080/14760584.2018.1411198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Polymorphism in vaccine antigens poses major challenges to vaccinologists. The Plasmodium falciparum Apical Membrane Antigen 1 (AMA1) poses such a challenge. We found that immunization with a mixture of three variants yielded functional antibody levels to all variants comparable to levels induced by monovalent immunization. The mechanism behind the observed broadening was shown to be an increase in the fraction of cross-reactive antibodies, most likely because strain-specific epitopes are present at lower frequency relative to conserved epitopes. Areas covered: We hereby introduce the Epitope Dilution Phenomenon (EDiP) as a practical strategy for the induction of broad, cross-variant antibody responses against polymorphic antigens and discuss the utility and applicability of this phenomenon for the development of vaccines against polymorphic antigens of pathogens like Influenza, HIV, Dengue and Plasmodium. Expert commentary: EDiP can be used to broaden antibody responses by immunizing with a mixture of at least 3 antigenic variants, where the variants included can differ, yet yield broadened responses.
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Affiliation(s)
- Kwadwo Asamoah Kusi
- a Immunology Department , Noguchi Memorial Institute for Medical Research, College of Health Sciences University of Ghana , Accra , Ghana
| | - Bart W Faber
- b Department of Parasitology , Biomedical Primate Research Centre , Rijswijk , The Netherlands
| | - Gerrit Koopman
- c Department of Virology , Biomedical Primate Research Centre , Rijswijk , The Netherlands
| | - Edmond Joseph Remarque
- c Department of Virology , Biomedical Primate Research Centre , Rijswijk , The Netherlands
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7
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Kusi KA, Manu EA, Manful Gwira T, Kyei-Baafour E, Dickson EK, Amponsah JA, Remarque EJ, Faber BW, Kocken CHM, Dodoo D, Gyan BA, Awandare GA, Atuguba F, Oduro AR, Koram KA. Variations in the quality of malaria-specific antibodies with transmission intensity in a seasonal malaria transmission area of Northern Ghana. PLoS One 2017; 12:e0185303. [PMID: 28945794 PMCID: PMC5612719 DOI: 10.1371/journal.pone.0185303] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 09/11/2017] [Indexed: 02/07/2023] Open
Abstract
Introduction Plasmodium falciparum induced antibodies are key components of anti-malarial immunity in malaria endemic areas, but their antigen targets can be polymorphic. Induction of a high proportion of strain-specific antibodies will limit the recognition of a broad diversity of parasite strains by these responses. There are indications that circulating parasite diversity varies with malaria transmission intensity, and this may affect the specificity of elicited anti-malarial antibodies. This study therefore assessed the effect of varying malaria transmission patterns on the specificity of elicited antibody responses and to identify possible antibody correlates of naturally acquired immunity to malaria in children in an area of Ghana with seasonal malaria transmission. Methods This retrospective study utilized plasma samples collected longitudinally at six time points from children aged one to five years. Multiplex assays were used to measure antibody levels against four P. falciparum AMA 1 variants (from the 3D7, FVO, HB3 and CAMP parasite strains) and the 3D7 variant of the EBA 175 region II antigen and the levels compared between symptomatic and asymptomatic children. The relative proportions of cross-reactive and strain-specific antibodies against the four AMA 1 variants per sampling time point were assessed by Bland-Altman plots. The levels of antibodies against allelic AMA1 variants, measured by singleplex and multiplex luminex assays, were also compared. Results The data show that increased transmission intensity is associated with higher levels of cross-reactive antibody responses, most likely a result of a greater proportion of multiple parasite clone infections during the high transmission period. Anti-AMA1 antibodies were however associated with a history of infection rather than protection in this age group. Conclusion The data contribute to understanding the underlying mechanism of the acquisition of strain-transcending antibody immunity following repeated exposure to diverse parasite strains.
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Affiliation(s)
- Kwadwo A. Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
- * E-mail:
| | - Emmanuel A. Manu
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Theresa Manful Gwira
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Eric Kyei-Baafour
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Emmanuel K. Dickson
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Jones A. Amponsah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Edmond J. Remarque
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Bart W. Faber
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Clemens H. M. Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Daniel Dodoo
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Ben A. Gyan
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Gordon A. Awandare
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Frank Atuguba
- Navrongo Health Research Centre, Ghana Health Service, Navrongo, Ghana
| | - Abraham R. Oduro
- Navrongo Health Research Centre, Ghana Health Service, Navrongo, Ghana
| | - Kwadwo A. Koram
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
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Tijani MK, Babalola OA, Odaibo AB, Anumudu CI, Asinobi AO, Morenikeji OA, Asuzu MC, Langer C, Reiling L, Beeson JG, Wahlgren M, Nwuba RI, Persson KEM. Acquisition, maintenance and adaptation of invasion inhibitory antibodies against Plasmodium falciparum invasion ligands involved in immune evasion. PLoS One 2017; 12:e0182187. [PMID: 28787025 PMCID: PMC5546579 DOI: 10.1371/journal.pone.0182187] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 07/13/2017] [Indexed: 11/18/2022] Open
Abstract
Erythrocyte-binding antigens (EBAs) and P. falciparum reticulocyte-binding homologue proteins (PfRhs) are two important protein families that can vary in expression and utilization by P. falciparum to evade inhibitory antibodies. We evaluated antibodies at repeated time-points among individuals living in an endemic region in Nigeria over almost one year against these vaccine candidates. Antibody levels against EBA140, EBA175, EBA181, PfRh2, PfRh4, and MSP2, were measured by ELISA. We also used parasites with disrupted EBA140, EBA175 and EBA181 genes to show that all these were targets of invasion inhibitory antibodies. However, antigenic targets of inhibitory antibodies were not stable and changed substantially over time in most individuals, independent of age. Antibodies levels measured by ELISA also varied within and between individuals over time and the antibodies against EBA181, PfRh2 and MSP2 declined more rapidly in younger individuals (≤15 years) compared with older (>15). The breadth of high antibody responses over time was more influenced by age than by the frequency of infection. High antibody levels were associated with a more stable invasion inhibitory response, which could indicate that during the long process of formation of immunity, many changes not only in levels but also in functional responses are needed. This is an important finding in understanding natural immunity against malaria, which is essential for making an efficacious vaccine.
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Affiliation(s)
- Muyideen K. Tijani
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Oluwatoyin A. Babalola
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Alex B. Odaibo
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Chiaka I. Anumudu
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Adanze O. Asinobi
- Department of Paediatrics, University College Hospital, University of Ibadan, Ibadan, Nigeria
| | - Olajumoke A. Morenikeji
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Michael C. Asuzu
- Department of Preventive Medicine and Primary Care, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Christine Langer
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Linda Reiling
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - James G. Beeson
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Roseangela I. Nwuba
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Kristina E. M. Persson
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
- Department of Laboratory Medicine, University Hospital, Lund University, Lund, Sweden
- * E-mail:
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9
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Spiegel H, Boes A, Fendel R, Reimann A, Schillberg S, Fischer R. Immunization with the Malaria Diversity-Covering Blood-Stage Vaccine Candidate Plasmodium falciparum Apical Membrane Antigen 1 DiCo in Complex with Its Natural Ligand PfRon2 Does Not Improve the In Vitro Efficacy. Front Immunol 2017; 8:743. [PMID: 28702028 PMCID: PMC5484772 DOI: 10.3389/fimmu.2017.00743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/12/2017] [Indexed: 01/05/2023] Open
Abstract
The blood-stage malaria vaccine candidate Plasmodium falciparum apical membrane antigen 1 (PfAMA1) can induce strong parasite growth-inhibitory antibody responses in animals but has not achieved the anticipated efficacy in clinical trials. Possible explanations in humans are the insufficient potency of the elicited antibody responses, as well as the high degree of sequence polymorphisms found in the field. Several strategies have been developed to improve the cross-strain coverage of PfAMA1-based vaccines, whereas innovative concepts to increase the potency of PfAMA1-specific IgG responses have received little attention even though this may be an essential requirement for protective efficacy. A previous study has demonstrated that immunization with a complex of PyAMA1 and PyRON2, a ligand with an essential functional role in erythrocyte invasion, leads to protection from lethal Plasmodium yoelli challenge in an animal model and suggested to extend this strategy toward improved strain coverage by using multiple PfAMA1 alleles in combination with PfRon2L. As an alternative approach along this line, we decided to use PfRon2L in combination with three PfAMA1 diversity covering variants (DiCo) to investigate the potential of this complex to induce more potent parasite growth inhibitory immune response in combination with better cross-strain-specific efficacy. Within the limits of the study design, the ability of the PfAMA1 DiCo-Mix to induce cross-strain-specific antibodies was not affected in all immunization groups, but the DiCo-PfRon2L complexes did not improve the potency of PfAMA1-specific IgG responses.
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Affiliation(s)
- Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Alexander Boes
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.,Institute for Phytopathology and Applied Zoology, Justus-Liebig University Giessen, Giessen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.,RWTH Aachen University, Institute for Molecular Biotechnology, Aachen, Germany.,Indiana Biosciences Research Institute (IBRI), Indianapolis, IN, United States
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10
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Abstract
There have been significant decreases in malaria mortality and morbidity in the last 10-15 years, and the most advanced pre-erythrocytic malaria vaccine, RTS,S, received a positive opinion from European regulators in July 2015. However, no blood-stage vaccine has reached a phase III trial. The first part of this review summarizes the pros and cons of various assays and models that have been and will be used to predict the efficacy of blood-stage vaccines. In the second part, blood-stage vaccine candidates that showed some efficacy in human clinical trials or controlled human malaria infection models are discussed. Then, candidates under clinical investigation are described in the third part, and other novel candidates and strategies are reviewed in the last part.
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Affiliation(s)
- Kazutoyo Miura
- a Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases , National Institutes of Health , Rockville , MD , USA
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11
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Spiegel H, Boes A, Kastilan R, Kapelski S, Edgue G, Beiss V, Chubodova I, Scheuermayer M, Pradel G, Schillberg S, Reimann A, Fischer R. The stage-specific in vitro efficacy of a malaria antigen cocktail provides valuable insights into the development of effective multi-stage vaccines. Biotechnol J 2015; 10:1651-9. [PMID: 25913888 DOI: 10.1002/biot.201500055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 03/18/2015] [Accepted: 04/21/2015] [Indexed: 11/06/2022]
Abstract
Multicomponent vaccines targeting different stages of Plasmodium falciparum represent a promising, holistic concept towards better malaria vaccines. Additionally, an effective vaccine candidate should demonstrate cross-strain specificity because many antigens are polymorphic, which can reduce vaccine efficacy. A cocktail of recombinant fusion proteins (VAMAX-Mix) featuring three diversity-covering variants of the blood-stage antigen PfAMA1, each combined with the conserved sexual-stage antigen Pfs25 and one of the pre-erythrocytic-stage antigens PfCSP_TSR or PfCelTOS, or the additional blood-stage antigen PfMSP1_19, was produced in Pichia pastoris and used to immunize rabbits. The immune sera and purified IgG were used to perform various assays determining antigen specific titers and in vitro efficacy against different parasite stages and strains. In functional in vitro assays we observed robust inhibition of blood-stage (up to 90%), and sexual-stage parasites (up to 100%) and biased inhibition of pre-erythrocytic parasites (0-40%). Cross-strain blood-stage efficacy was observed in erythrocyte invasion assays using four different P. falciparum strains. The quantification of antigen-specific IgGs allowed the determination of specific IC50 values. The significant difference in antigen-specific IC50 requirements, the direct correlation between antigen-specific IgG and the relative quantitative representation of antigens within the cocktail, provide valuable implementations for future multi-stage, multi-component vaccine designs.
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Affiliation(s)
- Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
| | - Alexander Boes
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Robin Kastilan
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Stephanie Kapelski
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Güven Edgue
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Veronique Beiss
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Ivana Chubodova
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | | | - Gabriele Pradel
- RWTH Aachen University, Institute of Molecular Biotechnology, Aachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.,RWTH Aachen University, Institute of Molecular Biotechnology, Aachen, Germany
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12
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Faber BW, Abdul Kadir K, Rodriguez-Garcia R, Remarque EJ, Saul FA, Vulliez-Le Normand B, Bentley GA, Kocken CHM, Singh B. Low levels of polymorphisms and no evidence for diversifying selection on the Plasmodium knowlesi Apical Membrane Antigen 1 gene. PLoS One 2015; 10:e0124400. [PMID: 25881166 PMCID: PMC4400157 DOI: 10.1371/journal.pone.0124400] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/03/2015] [Indexed: 11/19/2022] Open
Abstract
Infection with Plasmodium knowlesi, a zoonotic primate malaria, is a growing human health problem in Southeast Asia. P. knowlesi is being used in malaria vaccine studies, and a number of proteins are being considered as candidate malaria vaccine antigens, including the Apical Membrane Antigen 1 (AMA1). In order to determine genetic diversity of the ama1 gene and to identify epitopes of AMA1 under strongest immune selection, the ama1 gene of 52 P. knowlesi isolates derived from human infections was sequenced. Sequence analysis of isolates from two geographically isolated regions in Sarawak showed that polymorphism in the protein is low compared to that of AMA1 of the major human malaria parasites, P. falciparum and P. vivax. Although the number of haplotypes was 27, the frequency of mutations at the majority of the polymorphic positions was low, and only six positions had a variance frequency higher than 10%. Only two positions had more than one alternative amino acid. Interestingly, three of the high-frequency polymorphic sites correspond to invariant sites in PfAMA1 or PvAMA1. Statistically significant differences in the quantity of three of the six high frequency mutations were observed between the two regions. These analyses suggest that the pkama1 gene is not under balancing selection, as observed for pfama1 and pvama1, and that the PkAMA1 protein is not a primary target for protective humoral immune responses in their reservoir macaque hosts, unlike PfAMA1 and PvAMA1 in humans. The low level of polymorphism justifies the development of a single allele PkAMA1-based vaccine.
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Affiliation(s)
- Bart W. Faber
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
- * E-mail: (BWF); (BS)
| | - Khamisah Abdul Kadir
- Malaria Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kuching, Sarawak, Malaysia
| | | | - Edmond J Remarque
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Frederick A. Saul
- Institut Pasteur, Unité d’Immunologie Structurale, Département de Biologie Structurale et Chimie, Paris, France
- CNRS URA 2185, Paris, France
| | - Brigitte Vulliez-Le Normand
- Institut Pasteur, Unité d’Immunologie Structurale, Département de Biologie Structurale et Chimie, Paris, France
- CNRS URA 2185, Paris, France
| | - Graham A. Bentley
- Institut Pasteur, Unité d’Immunologie Structurale, Département de Biologie Structurale et Chimie, Paris, France
- CNRS URA 2185, Paris, France
| | - Clemens H. M. Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Balbir Singh
- Malaria Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kuching, Sarawak, Malaysia
- * E-mail: (BWF); (BS)
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13
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Dutta S, Dlugosz LS, Drew DR, Ge X, Ababacar D, Rovira YI, Moch JK, Shi M, Long CA, Foley M, Beeson JG, Anders RF, Miura K, Haynes JD, Batchelor AH. Overcoming antigenic diversity by enhancing the immunogenicity of conserved epitopes on the malaria vaccine candidate apical membrane antigen-1. PLoS Pathog 2013; 9:e1003840. [PMID: 24385910 PMCID: PMC3873463 DOI: 10.1371/journal.ppat.1003840] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 11/04/2013] [Indexed: 12/16/2022] Open
Abstract
Malaria vaccine candidate Apical Membrane Antigen-1 (AMA1) induces protection, but only against parasite strains that are closely related to the vaccine. Overcoming the AMA1 diversity problem will require an understanding of the structural basis of cross-strain invasion inhibition. A vaccine containing four diverse allelic proteins 3D7, FVO, HB3 and W2mef (AMA1 Quadvax or QV) elicited polyclonal rabbit antibodies that similarly inhibited the invasion of four vaccine and 22 non-vaccine strains of P. falciparum. Comparing polyclonal anti-QV with antibodies against a strain-specific, monovalent, 3D7 AMA1 vaccine revealed that QV induced higher levels of broadly inhibitory antibodies which were associated with increased conserved face and domain-3 responses and reduced domain-2 response. Inhibitory monoclonal antibodies (mAb) raised against the QV reacted with a novel cross-reactive epitope at the rim of the hydrophobic trough on domain-1; this epitope mapped to the conserved face of AMA1 and it encompassed the 1e-loop. MAbs binding to the 1e-loop region (1B10, 4E8 and 4E11) were ∼10-fold more potent than previously characterized AMA1-inhibitory mAbs and a mode of action of these 1e-loop mAbs was the inhibition of AMA1 binding to its ligand RON2. Unlike the epitope of a previously characterized 3D7-specific mAb, 1F9, the 1e-loop inhibitory epitope was partially conserved across strains. Another novel mAb, 1E10, which bound to domain-3, was broadly inhibitory and it blocked the proteolytic processing of AMA1. By itself mAb 1E10 was weakly inhibitory but it synergized with a previously characterized, strain-transcending mAb, 4G2, which binds close to the hydrophobic trough on the conserved face and inhibits RON2 binding to AMA1. Novel inhibition susceptible regions and epitopes, identified here, can form the basis for improving the antigenic breadth and inhibitory response of AMA1 vaccines. Vaccination with a few diverse antigenic proteins could provide universal coverage by redirecting the immune response towards conserved epitopes. Numerous reports of vaccine failure are attributed to a mismatch between the genotype of the vaccine and the circulating target strains. This observation is congruent to the view that polyvalent vaccines protect broadly by inducing a multitude of type-specific antibodies. Polyvalent vaccines that can overcome antigenic diversity by refocusing antibody responses towards conserved functional epitopes are highly desirable. Development of an Apical Membrane Antigen-1 (AMA1) malaria vaccine has been impeded by extreme antigenic diversity in the field. We present here a solution to the AMA1 diversity problem. Antibodies against a mixture of only four naturally occurring AMA1 allelic proteins “Quadvax” inhibited invasion of red blood cells by a diverse panel of malaria parasites that represented the global diversity of AMA1 in the field. Competition experiments suggested that in addition to improving the diversity of strain-specific antibodies, the mechanism of broadened inhibition involved an increase in responses against conserved inhibitory epitopes. Monoclonal antibodies against the Quadvax inhibited invasion either by blocking the binding of AMA1 to its receptor RON2 or by blocking a crucial proteolytic processing event. Some mixtures of these antibodies were much more effective than expected and were shown to act synergistically. Together these two classes of functional invasion inhibitory epitopes can be targeted to engineer a more potent AMA1 vaccine.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antigenic Variation/genetics
- Antigenic Variation/immunology
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Cells, Cultured
- Conserved Sequence/immunology
- Epitope Mapping
- Epitopes/genetics
- Epitopes/immunology
- Immunity, Humoral
- Malaria Vaccines/chemistry
- Malaria Vaccines/immunology
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/immunology
- Mice
- Mice, Nude
- Models, Molecular
- Plasmodium berghei/genetics
- Plasmodium berghei/immunology
- Plasmodium falciparum/immunology
- Protein Structure, Tertiary
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Rabbits
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/immunology
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Affiliation(s)
- Sheetij Dutta
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- * E-mail:
| | - Lisa S. Dlugosz
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | | | - Xiopeng Ge
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Diouf Ababacar
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yazmin I. Rovira
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - J. Kathleen Moch
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Meng Shi
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Michael Foley
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | | | - Robin F. Anders
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - J. David Haynes
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Adrian H. Batchelor
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
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14
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Faber BW, Younis S, Remarque EJ, Rodriguez Garcia R, Riasat V, Walraven V, van der Werff N, van der Eijk M, Cavanagh DR, Holder AA, Thomas AW, Kocken CHM. Diversity covering AMA1-MSP119 fusion proteins as malaria vaccines. Infect Immun 2013; 81:1479-90. [PMID: 23429538 PMCID: PMC3648017 DOI: 10.1128/iai.01267-12] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 02/13/2013] [Indexed: 11/20/2022] Open
Abstract
To overcome polymorphism in the malaria vaccine candidate Plasmodium falciparum apical membrane antigen 1 (PfAMA1), fusion protein chimeras comprised of three diversity-covering (DiCo) PfAMA1 molecules (D1, D2, and D3) and two allelic variants of the C-terminal 19-kDa region of merozoite surface protein 1 (MSP119) (variants M1 and M2) were generated. A mixture of fusion proteins (D1M1/D2M2D3) and the D1M1D2M2D3 fusion were compared to a single-unit mixture (D1/D2/D3/M1) in an immunological study in groups of rabbits. Following immunization, titers of antibodies (Abs) against four naturally occurring PfAMA1 alleles were high for all groups, as were growth inhibition assay (GIA) levels against two antigenically distinct laboratory parasite strains. Fusion of AMA1 to MSP119 did not suppress levels of antibodies against the AMA1 component. In addition, the breadth of antibody responses was unaffected. Anti-AMA1 antibodies were largely responsible for parasite growth inhibition, as shown in reversal-of-inhibition experiments by adding competing AMA1 antigen. For all groups, titration of the MSP119 antigen into the GIA led to only a small decrease in parasite inhibition, although titers of antibodies against MSP119 were increased 15-fold for the groups immunized with fusion proteins. GIA with affinity-purified anti-MSP119 antibodies showed that the 50% inhibitory concentrations of the anti-MSP119 antibody preparations were in the same order of magnitude for all animals tested, leading to the conclusion that fusing MSP119 to PfAMA1 leads to a small but significant increase in functional antibody levels. This study shows that combination of multiple vaccine candidates in fusion proteins may lead to improved characteristics of the vaccine.
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Affiliation(s)
- Bart W. Faber
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Sumera Younis
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Edmond J. Remarque
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | | | - Vanessa Riasat
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Vanessa Walraven
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Nicole van der Werff
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Marjolein van der Eijk
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - David R. Cavanagh
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Anthony A. Holder
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Alan W. Thomas
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Clemens H. M. Kocken
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
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15
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Ouattara A, Takala-Harrison S, Thera MA, Coulibaly D, Niangaly A, Saye R, Tolo Y, Dutta S, Heppner DG, Soisson L, Diggs CL, Vekemans J, Cohen J, Blackwelder WC, Dube T, Laurens MB, Doumbo OK, Plowe CV. Molecular basis of allele-specific efficacy of a blood-stage malaria vaccine: vaccine development implications. J Infect Dis 2012. [PMID: 23204168 DOI: 10.1093/infdis/jis709] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The disappointing efficacy of blood-stage malaria vaccines may be explained in part by allele-specific immune responses that are directed against polymorphic epitopes on blood-stage antigens. FMP2.1/AS02(A), a blood-stage candidate vaccine based on apical membrane antigen 1 (AMA1) from the 3D7 strain of Plasmodium falciparum, had allele-specific efficacy against clinical malaria in a phase II trial in Malian children. We assessed the cross-protective efficacy of the malaria vaccine and inferred which polymorphic amino acid positions in AMA1 were the targets of protective allele-specific immune responses. FMP2.1/AS02(A) had the highest efficacy against AMA1 alleles that were identical to the 3D7 vaccine-type allele at 8 highly polymorphic amino acid positions in the cluster 1 loop (c1L) but differed from 3D7 elsewhere in the molecule. Comparison of the incidence of vaccine-type alleles before and after vaccination in the malaria vaccine and control groups and examination of the patterns of allele change at polymorphic positions in consecutive malaria episodes suggest that the highly polymorphic amino acid position 197 in c1L was the most critical determinant of allele-specific efficacy. These results indicate that a multivalent AMA1 vaccine with broad efficacy could include only a limited set of key alleles of this extremely polymorphic antigen.
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Affiliation(s)
- Amed Ouattara
- Malaria Research and Training Center, University of Sciences, Techniques and Technology, Bamako, Mali
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16
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Remarque EJ, Roestenberg M, Younis S, Walraven V, van der Werff N, Faber BW, Leroy O, Sauerwein R, Kocken CHM, Thomas AW. Humoral immune responses to a single allele PfAMA1 vaccine in healthy malaria-naïve adults. PLoS One 2012; 7:e38898. [PMID: 22768052 PMCID: PMC3387192 DOI: 10.1371/journal.pone.0038898] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 05/14/2012] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Plasmodium falciparum: apical membrane antigen 1 (AMA1) is a candidate malaria vaccine antigen expressed on merozoites and sporozoites. The polymorphic nature of AMA1 may compromise vaccine induced protection. The humoral response induced by two dosages (10 and 50 µg) of a single allele AMA1 antigen (FVO) formulated with Alhydrogel, Montanide ISA 720 or AS02 was investigated in 47 malaria-naïve adult volunteers. Volunteers were vaccinated 3 times at 4 weekly intervals and serum samples obtained four weeks after the third immunization were analysed for (i) Antibody responses to various allelic variants, (ii) Domain specificity, (iii) Avidity, (iv) IgG subclass levels, by ELISA and (v) functionality of antibody responses by Growth Inhibition Assay (GIA). About half of the antibodies induced by vaccination cross reacted with heterologous AMA1 alleles. The choice of adjuvant determined the magnitude of the antibody response, but had only a marginal influence on specificity, avidity, domain recognition or subclass responses. The highest antibody responses were observed for AMA1 formulated with AS02. The Growth Inhibition Assay activity of the antibodies was proportional to the amount of antigen specific IgG and the functional capacity of the antibodies was similar for heterologous AMA1-expressing laboratory strains. TRIAL REGISTRATION ClinicalTrials.gov NCT00730782.
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17
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Kusi KA, Dodoo D, Bosomprah S, van der Eijk M, Faber BW, Kocken CHM, Remarque EJ. Measurement of the plasma levels of antibodies against the polymorphic vaccine candidate apical membrane antigen 1 in a malaria-exposed population. BMC Infect Dis 2012; 12:32. [PMID: 22299616 PMCID: PMC3317819 DOI: 10.1186/1471-2334-12-32] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 02/02/2012] [Indexed: 11/24/2022] Open
Abstract
Background Establishing antibody correlates of protection against malaria in human field studies and clinical trials requires, amongst others, an accurate estimation of antibody levels. For polymorphic antigens such as apical membrane antigen 1 (AMA1), this may be confounded by the occurrence of a large number of allelic variants in nature. Methods To test this hypothesis, plasma antibody levels in an age-stratified cohort of naturally exposed children from a malaria-endemic area in Southern Ghana were determined by indirect ELISA. Titres against four single PfAMA1 alleles were compared with those against three different allele mixtures presumed to have a wider repertoire of epitope specificities. Associations of antibody levels with the incidence of clinical malaria as well as with previous exposure to parasites were also examined. Results Antibody titres against PfAMA1 alleles generally increased with age/exposure while antibody specificity for PfAMA1 variants decreased, implying that younger children (≤ 5 years) elicit a more strain-specific antibody response compared to older children. Antibody titre measurements against the FVO and 3D7 AMA1 alleles gave the best titre estimates as these varied least in pair-wise comparisons with titres against all PfAMA1 allele mixtures. There was no association between antibody levels against any capture antigen and either clinical malaria incidence or parasite density. Conclusions The current data shows that levels of naturally acquired antigen-specific antibodies, especially in infants and young children, are dependent on the antigenic allele used for measurement. This may be relevant to the interpretation of antibody titre data from measurements against single PfAMA1 alleles, especially in studies involving infants and young children who have experienced fewer infections.
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Affiliation(s)
- Kwadwo A Kusi
- Department of Parasitology, Biomedical Primate Research Centre, Postbox 3306, 2280, GH Rijswijk, The Netherlands.
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