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Rittipornlertrak A, Nambooppha B, Muenthaisong A, Apinda N, Koonyosying P, Srisawat W, Chomjit P, Sangkakam K, Punyapornwithaya V, Tiwananthagorn S, Yokoyama N, Sthitmatee N. Immunization of Cattle With Recombinant Structural Ectodomains I and II of Babesia bovis Apical Membrane Antigen 1 [BbAMA-1(I/II)] Induces Strong Th1 Immune Response. Front Vet Sci 2022; 9:917389. [PMID: 35812841 PMCID: PMC9260583 DOI: 10.3389/fvets.2022.917389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/23/2022] [Indexed: 12/04/2022] Open
Abstract
Both strong innate and adaptive immune responses are an important component of protection against intraerythrocytic protozoan parasites. Resistance to bovine babesiosis is associated with interferon (IFN)-γ mediated responses. CD4+ T cells and macrophages have been identified as major effector cells mediating the clearance of pathogens. Previously, the apical membrane antigen 1 (AMA-1) was found to significantly induce the immune response inhibiting B. bovis merozoite growth and invasion. However, a detailed characterization of both humoral and cellular immune responses against the structure of B. bovis AMA-1 (BbAMA-1) has not yet been established. Herein, the present study aimed to express the recombinant BbAMA-1 domain I+II protein [rBbAMA-1(I/II)], which is the most predominant immune response region, and to characterize its immune response. As a result, cattle vaccinated with BbAMA-1(I/II) significantly developed high titters of total immunoglobulin (Ig) G antibodies and a high ratio of IgG2/IgG1 when compared to control groups. Interestingly, the BbAMA-1(I/II)-based formulations produced in our study could elicit CD4+ T cells and CD8+ T cells producing IFN-γ and tumor necrosis factor (TNF)-α. Collectively, the results indicate that immunization of cattle with BbAMA-1(I/II) could induce strong Th1 cell responses. In support of this, we observed the up-regulation of Th1 cytokine mRNA transcripts, including IFN-γ, TNF-α, Interleukin (IL)-2 and IL-12, in contrast to down regulation of IL-4, IL-6 and IL-10, which would be indicative of a Th2 cytokine response. Moreover, the up-regulation of inducible nitric oxide synthase (iNOS) was observed. In conclusion, this is the first report on the in-depth immunological characterization of the response to BbAMA-1. According to our results, BbAMA-1 is recognized as a potential candidate vaccine against B. bovis infection. As evidenced by the Th1 cell response, it could potentially provide protective immunity. However, further challenge-exposure with virulent B. bovis strain in immunized cattle would be needed to determine its protective efficacy.
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Affiliation(s)
- Amarin Rittipornlertrak
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Ruminant Clinic, Department of Food Animal Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Boondarika Nambooppha
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Anucha Muenthaisong
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Nisachon Apinda
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pongpisid Koonyosying
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Wanwisa Srisawat
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Paweena Chomjit
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Kanokwan Sangkakam
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Veerasak Punyapornwithaya
- Ruminant Clinic, Department of Food Animal Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Saruda Tiwananthagorn
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Nattawooti Sthitmatee
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Excellent Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai, Thailand
- *Correspondence: Nattawooti Sthitmatee ;
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Seidel-Greven M, Addai-Mensah O, Spiegel H, Chiegoua Dipah GN, Schmitz S, Breuer G, Frempong M, Reimann A, Klockenbring T, Fischer R, Barth S, Fendel R. Isolation and light chain shuffling of a Plasmodium falciparum AMA1-specific human monoclonal antibody with growth inhibitory activity. Malar J 2021; 20:37. [PMID: 33430886 PMCID: PMC7798374 DOI: 10.1186/s12936-020-03548-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/12/2020] [Indexed: 11/25/2022] Open
Abstract
Background Plasmodium falciparum, the parasite causing malaria, affects populations in many endemic countries threatening mainly individuals with low malaria immunity, especially children. Despite the approval of the first malaria vaccine Mosquirix™ and very promising data using cryopreserved P. falciparum sporozoites (PfSPZ), further research is needed to elucidate the mechanisms of humoral immunity for the development of next-generation vaccines and alternative malaria therapies including antibody therapy. A high prevalence of antibodies against AMA1 in immune individuals has made this antigen one of the major blood-stage vaccine candidates. Material and methods Using antibody phage display, an AMA1-specific growth inhibitory human monoclonal antibody from a malaria-immune Fab library using a set of three AMA1 diversity covering variants (DiCo 1–3), which represents a wide range of AMA1 antigen sequences, was selected. The functionality of the selected clone was tested in vitro using a growth inhibition assay with P. falciparum strain 3D7. To potentially improve affinity and functional activity of the isolated antibody, a phage display mediated light chain shuffling was employed. The parental light chain was replaced with a light chain repertoire derived from the same population of human V genes, these selected antibodies were tested in binding tests and in functionality assays. Results The selected parental antibody achieved a 50% effective concentration (EC50) of 1.25 mg/mL. The subsequent light chain shuffling led to the generation of four derivatives of the parental clone with higher expression levels, similar or increased affinity and improved EC50 against 3D7 of 0.29 mg/mL. Pairwise epitope mapping gave evidence for binding to AMA1 domain II without competing with RON2. Conclusion We have thus shown that a compact immune human phage display library is sufficient for the isolation of potent inhibitory monoclonal antibodies and that minor sequence mutations dramatically increase expression levels in Nicotiana benthamiana. Interestingly, the antibody blocks parasite inhibition independently of binding to RON2, thus having a yet undescribed mode of action.
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Affiliation(s)
- Melanie Seidel-Greven
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany
| | - Otchere Addai-Mensah
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany.,Department of Medical Diagnostics, Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany
| | - Gwladys Nina Chiegoua Dipah
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany
| | - Stefan Schmitz
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany
| | - Gudrun Breuer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany
| | - Margaret Frempong
- Department of Molecular Medicine, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany
| | - Torsten Klockenbring
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany.,Institute of Molecular Biotechnology (Biology VII), RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.,Purdue University, West Lafayette, IN, 47907, USA
| | - Stefan Barth
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany.,Department of Experimental Medicine and Immunotherapy, Institute of Applied Medical Engineering, RWTH Aachen University Clinic, Pauwelsstraße 20, 52074, Aachen, Germany.,South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, and Medical Biotechnology & Immunotherapy Research Unit, Institute of Infectious Disease & Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr.6, 52074, Aachen, Germany. .,Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.
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3
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Bittencourt NC, da Silva ABIE, Virgili NS, Schappo AP, Gervásio JHDB, Pimenta TS, Kujbida Junior MA, Ventura AMRS, Libonati RMF, Silva-Filho JL, dos Santos HG, Lopes SCP, Lacerda MVG, Machado RLD, Costa FTM, Albrecht L. Plasmodium vivax AMA1: Implications of distinct haplotypes for immune response. PLoS Negl Trop Dis 2020; 14:e0008471. [PMID: 32639964 PMCID: PMC7371208 DOI: 10.1371/journal.pntd.0008471] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 07/20/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023] Open
Abstract
In Brazil, Plasmodium vivax infection accounts for around 80% of malaria cases. This infection has a substantial impact on the productivity of the local population as the course of the disease is usually prolonged and the development of acquired immunity in endemic areas takes several years. The recent emergence of drug-resistant strains has intensified research on alternative control methods such as vaccines. There is currently no effective available vaccine against malaria; however, numerous candidates have been studied in the past several years. One of the leading candidates is apical membrane antigen 1 (AMA1). This protein is involved in the invasion of Apicomplexa parasites into host cells, participating in the formation of a moving junction. Understanding how the genetic diversity of an antigen influences the immune response is highly important for vaccine development. In this study, we analyzed the diversity of AMA1 from Brazilian P. vivax isolates and 19 haplotypes of P. vivax were found. Among those sequences, 33 nonsynonymous PvAMA1 amino acid sites were identified, whereas 20 of these sites were determined to be located in predicted B-cell epitopes. Nonsynonymous mutations were evaluated for their influence on the immune recognition of these antigens. Two distinct haplotypes, 5 and 16, were expressed and evaluated for reactivity in individuals from northern Brazil. Both PvAMA1 variants were reactive. Moreover, the IgG antibody response to these two PvAMA1 variants was analyzed in an exposed but noninfected population from a P. vivax endemic area. Interestingly, over 40% of this population had antibodies recognizing both variants. These results have implications for the design of a vaccine based on a polymorphic antigen. Plasmodium vivax is the most abundant Plasmodium species in Brazil. While this species has been neglected for many years, the recent emergence of drug-resistant strains and the absence of a vaccine intensified the efforts for a better control method. Naturally acquired immune response analysis is a useful tool for understanding the antigenicity of Plasmodium proteins and evaluating the potential of a vaccine candidate. In this study, the genetic variability of one of the leading P. vivax vaccine candidates (PvAMA1) was analyzed. Two distinct variants were expressed and the antibody response was evaluated in infected and noninfected individuals in the Brazilian Amazon. This improved understanding of the magnitude and dynamics of the antibody response will contribute to the knowledge of a vaccine candidate and open new perspectives in vivax malaria vaccine development.
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Affiliation(s)
- Najara Carneiro Bittencourt
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | | | - Natália Silveira Virgili
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Ana Paula Schappo
- Instituto Carlos Chagas, Fundação Oswaldo Cruz–FIOCRUZ. Curitiba, PR, Brazil
| | | | - Tamirys S. Pimenta
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, PA, Brazil
| | | | | | | | - João Luiz Silva-Filho
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | | | - Stefanie C. P. Lopes
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Gerência de Malária, Manaus, AM, Brazil
- Instituto Leônidas & Maria Deane, FIOCRUZ-AMAZONAS, Manaus, AM, Brazil
| | - Marcus V. G. Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Gerência de Malária, Manaus, AM, Brazil
- Instituto Leônidas & Maria Deane, FIOCRUZ-AMAZONAS, Manaus, AM, Brazil
| | - Ricardo L. D. Machado
- Centro de Investigação de Microrganismos, Universidade Federal Fluminense, RJ, Brazil
| | - Fabio T. M. Costa
- Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Letusa Albrecht
- Instituto Carlos Chagas, Fundação Oswaldo Cruz–FIOCRUZ. Curitiba, PR, Brazil
- * E-mail: ,
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Drew DR, Sanders PR, Weiss G, Gilson PR, Crabb BS, Beeson JG. Functional Conservation of the AMA1 Host-Cell Invasion Ligand Between P. falciparum and P. vivax: A Novel Platform to Accelerate Vaccine and Drug Development. J Infect Dis 2019; 217:498-507. [PMID: 29165651 DOI: 10.1093/infdis/jix583] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/17/2017] [Indexed: 01/20/2023] Open
Abstract
Plasmodium vivax and P. falciparum malaria species have diverged significantly in receptor-ligand interactions and host-cell invasion. One protein common to both is the merozoite invasion ligand AMA1. While the general structure of AMA1 is similar between species, their sequences are divergent. Surprisingly, it was possible to genetically replace PfAMA1 with PvAMA1 in P. falciparum parasites. PvAMA1 complemented PfAMA1 function and supported invasion of erythrocytes by P. falciparum. Genetically modified P. falciparum expressing PvAMA1 evaded the invasion inhibitory effects of antibodies to PfAMA1, demonstrating species specificity of functional antibodies. We generated antibodies to recombinant PvAMA1 that effectively inhibited invasion, confirming the function of PvAMA1 in genetically modified parasites. Results indicate significant molecular flexibility in AMA1 enabling conserved function despite substantial sequence divergence across species. This provides powerful new tools to quantify the inhibitory activities of antibodies or drugs targeting PvAMA1, opening new opportunities for vaccine and therapeutic development against P. vivax.
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Affiliation(s)
| | | | | | | | - Brendan S Crabb
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Victoria, Australia.,Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Victoria, Australia.,Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia.,Central Clinical School and Department of Microbiology, Monash University, Victoria, Australia
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5
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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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6
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Molecular cloning, characterization and antigenicity ofBabesiasp. BQ1 (Lintan) (Babesiacf.motasi) apical membrane antigen-1 (AMA-1). Parasitology 2016; 144:641-649. [DOI: 10.1017/s0031182016002304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYApical membrane antigen-1 (AMA-1) has been described as a potential vaccine candidate in apicomplexan parasites. Here we characterize theama-1gene. The full-lengthama-1gene ofBabesiasp. BQ1 (Lintan) (BLTAMA-1) is 1785 bp, which contains an open reading frame (ORF) encoding a 65-kDa protein of 594 amino acid residues; by definition, the 5′ UTR precedes the first methionine of the ORF. Phylogenetic analysis based on AMA-1 amino acid sequences clearly separated Piroplasmida from other Apicomplexa parasites. TheBabesiasp. BQ1 (Lintan) AMA-1 sequence is most closely associated with that ofB. ovataandB. bigemina, with high bootstrap value. A recombinant protein encoding a conserved region and containing ectodomains I and II of BLTAMA-1 was constructed. BLTrAMA-1-DI/DII proteins were tested for reactivity with sera from sheep infected byBabesiasp. BQ1 (Lintan). In Western-blot analysis, nativeBabesiasp. BQ1 (Lintan) AMA-1 proteins were recognized by antibodies raised in rabbits against BLTrAMA-1in vitro. The results of this study are discussed in terms of gene characterization, taxonomy and antigenicity.
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Imboumy-Limoukou RK, Oyegue-Liabagui SL, Ndidi S, Pegha-Moukandja I, Kouna CL, Galaway F, Florent I, Lekana-Douki JB. Comparative Antibody Responses Against three Antimalarial Vaccine Candidate Antigens from Urban and Rural Exposed Individuals in Gabon. Eur J Microbiol Immunol (Bp) 2016; 6:287-297. [PMID: 27980857 PMCID: PMC5146647 DOI: 10.1556/1886.2016.00027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 08/15/2016] [Indexed: 12/12/2022] Open
Abstract
The analysis of immune responses in diverse malaria endemic regions provides more information to understand the host's immune response to Plasmodium falciparum. Several plasmodial antigens have been reported as targets of human immunity. PfAMA1 is one of most studied vaccine candidates; PfRH5 and Pf113 are new promising vaccine candidates. The aim of this study was to evaluate humoral response against these three antigens among children of Lastourville (rural area) and Franceville (urban area). Malaria was diagnosed using rapid diagnosis tests. Plasma samples were tested against these antigens by enzyme-linked immunosorbent assay (ELISA). We found that malaria prevalence was five times higher in the rural area than in the urban area (p < 0.0001). The anti-PfAMA1 and PfRh5 response levels were significantly higher in Lastourville than in Franceville (p < 0.0001; p = 0.005). The anti-AMA1 response was higher than the anti-Pf113 response, which in turn was higher than the anti-PfRh5 response in both sites. Anti-PfAMA1 levels were significantly higher in infected children than those in uninfected children (p = 0.001) in Franceville. Anti-Pf113 and anti-PfRh5 antibody levels were lowest in children presenting severe malarial anemia. These three antigens are targets of immunity in Gabon. Further studies on the role of Pf113 in antimalarial protection against severe anemia are needed.
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Affiliation(s)
- Roméo-Karl Imboumy-Limoukou
- Unité de Parasitologie Médicale (UPARAM), Centre International de Recherches Médicales de Franceville (CIRMF), BP 769 Franceville, Gabon; Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Sorbonne Universités, Muséum National d'Histoire Naturelle, CNRS, CP52, 57 rue Cuvier 75005 Paris, France; Ecole Doctorale Régionale en Infectiologie Tropicale d'Afrique Centrale (ECODRAC), BP 876 Franceville, Gabon
| | - Sandrine Lydie Oyegue-Liabagui
- Laboratoire de Recherches en Immunologie, Parasitologie et Microbiologie, Ecole Doctorale Régionale en Infectiologie Tropicale d'Afrique Centrale (ECODRAC) , BP 876 Franceville, Gabon
| | - Stella Ndidi
- Unité de Parasitologie Médicale (UPARAM), Centre International de Recherches Médicales de Franceville (CIRMF) , BP 769 Franceville, Gabon
| | - Irène Pegha-Moukandja
- Unité de Parasitologie Médicale (UPARAM), Centre International de Recherches Médicales de Franceville (CIRMF), BP 769 Franceville, Gabon; Ecole Doctorale Régionale en Infectiologie Tropicale d'Afrique Centrale (ECODRAC), BP 876 Franceville, Gabon
| | - Charlene Lady Kouna
- Unité de Parasitologie Médicale (UPARAM), Centre International de Recherches Médicales de Franceville (CIRMF) , BP 769 Franceville, Gabon
| | | | - Isabelle Florent
- Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Sorbonne Universités, Muséum National d'Histoire Naturelle, CNRS, CP52 , 57 rue Cuvier 75005 Paris, France
| | - Jean Bernard Lekana-Douki
- Unité de Parasitologie Médicale (UPARAM), Centre International de Recherches Médicales de Franceville (CIRMF), BP 769 Franceville, Gabon; Département de Parasitologie-Mycologie, Université des Sciences de la Santé, BP 4008 Libreville, Gabon
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Graves SF, Kouriba B, Diarra I, Daou M, Niangaly A, Coulibaly D, Keita Y, Laurens MB, Berry AA, Vekemans J, Ripley Ballou W, Lanar DE, Dutta S, Gray Heppner D, Soisson L, Diggs CL, Thera MA, Doumbo OK, Plowe CV, Sztein MB, Lyke KE. Strain-specific Plasmodium falciparum multifunctional CD4+ T cell cytokine expression in Malian children immunized with the FMP2.1/AS02A vaccine candidate. Vaccine 2016; 34:2546-55. [DOI: 10.1016/j.vaccine.2016.04.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 03/24/2016] [Accepted: 04/07/2016] [Indexed: 12/17/2022]
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9
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Salavatifar M, Zakeri S, Hayati Roodbari N, Djadid ND. High-Level Expression, Purification and Characterization of A Recombinant Plasmodium vivax Apical Membrane Antigen 1: Implication for vivax Malaria Vaccine Development. CELL JOURNAL 2015; 17:520-31. [PMID: 26464824 PMCID: PMC4601873 DOI: 10.22074/cellj.2015.12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022]
Abstract
Objective The apical membrane antigen-1 (AMA-1) is considered as a promising candidate for development of a malaria vaccine against Plasmodium parasites. The correct
conformation of this protein appears to be necessary for the stimulation of parasite-inhibitory responses, and these responses, in turn, seem to be antibody-mediated. Therefore, in
the present investigation, we expressed the Plasmodium vivax AMA-1 (PvAMA-1) ectodomain in Escherichia coli (E. coli), purified it using standard procedures and characterized
it to determine its biological activities for it to be used as a potential target for developing
a protective and safe vivax malaria vaccine.
Materials and Methods In this experimental investigation, the ectodomain of PvAMA-1 antigen (GenBank accession no. JX624741) was expressed in the E. coli M15pQE30 expression system and purified with immobilized-metal affinity chromatography. The correct conformation of the recombinant protein was evaluated by Western
blotting and indirect immunofluorescence antibody (IFA) test. In addition, the immunogenic properties of PvAMA-1 were evaluated in BALB/c mice with the purified protein
emulsified in Freund’s adjuvant.
Results In the present study, the PvAMA-1 ectodomain was expressed at a high-level
(65 mg/L) using a bacterial system. Reduced and non-reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) as well as Western blot analysis
confirmed the appropriate conformation and folding of PvAMA-1. The evaluation of
immunogenic properties of PvAMA-1 showed that both T helper-1 and 2 cells (Th1
and Th2) responses were present in mice after three immunizations and persisted up
to one year after the first immunization. Moreover, the antibodies raised against the
recombinant PvAMA-1 in injected mice could recognize the native protein localized on
P. vivax parasites.
Conclusion We demonstrate that our recombinant protein had proper conformation
and folding. Also, there were common epitopes in the recombinant forms corresponding to native proteins. These results; therefore, indicate that the expressed PvAMA-1
has the potential to be used as a vivax malaria vaccine.
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Affiliation(s)
- Maryam Salavatifar
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BCR), Pasteur Institute of Iran, Tehran, Iran
| | - Nasim Hayati Roodbari
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Navid Dinparast Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BCR), Pasteur Institute of Iran, Tehran, Iran
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10
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Reddy SB, Anders RF, Cross N, Mueller I, Senn N, Stanisic DI, Siba PM, Wahlgren M, Kironde F, Beeson JG, Persson KEM. Differences in affinity of monoclonal and naturally acquired polyclonal antibodies against Plasmodium falciparum merozoite antigens. BMC Microbiol 2015; 15:133. [PMID: 26149471 PMCID: PMC4491891 DOI: 10.1186/s12866-015-0461-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 06/03/2015] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major global cause of deaths and a vaccine is urgently needed. Results We have employed the P. falciparum merozoite antigens MSP2-3D7/FC27 and AMA1, used them in ELISA, and coupled them in different ways using surface plasmon resonance (SPR) and estimated affinity (measured as kd) of monoclonal as well as naturally-acquired polyclonal antibodies in human plasma. There were major differences in kd depending on how the antigens were immobilized and where the His-tag was placed. For AMA1 we could see correlations with invasion inhibition. Using different immobilizations of proteins in SPR, we could see only moderate correlations with levels of antibodies in ELISA, indicating that in ELISA the proteins were not uniformly bound and that antibodies with many specificities exist in natural immunisation. The correlations between ELISA and SPR were enhanced when only parasite positive samples were included, which may indicate that high affinity antibodies are difficult to maintain over long periods of time. We found higher kd values for MSP2 (indicating lower affinity) compared to AMA1, which might be partly explained by MSP2 being an intrinsically disordered protein, while AMA1 is globular. Conclusions For future vaccine studies and for understanding immunity, it is important to consider how to present proteins to the immune system to achieve highest antibody affinities. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0461-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sreenivasulu B Reddy
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Robin F Anders
- Department of Biochemistry, La Trobe University, Vic, 3086, Australia
| | - Nadia Cross
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Ivo Mueller
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea
| | - Nicolas Senn
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Danielle I Stanisic
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea.,Institute for Glycomics, Griffith University, Queensland, Australia
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Fred Kironde
- Department of Biochemistry, Makerere University, Kampala, Uganda.,Habib Medical School, IUIU, Kampala, Uganda
| | - James G Beeson
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia.,The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Kristina E M Persson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden. .,Department of Laboratory Medicine, Lund University, 22185, Lund, Sweden.
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11
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Rouhani M, Zakeri S, Mehrizi AA, Djadid ND. Comparative analysis of the profiles of IgG subclass-specific responses to Plasmodium falciparum apical membrane antigen-1 and merozoite surface protein-1 in naturally exposed individuals living in malaria hypoendemic settings, Iran. Malar J 2015; 14:58. [PMID: 25652589 PMCID: PMC4365771 DOI: 10.1186/s12936-015-0547-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/06/2015] [Indexed: 01/27/2023] Open
Abstract
Background Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) and the 19-kDa C-terminal region of merozoite surface protein-1 (PfMSP-119) are candidate malaria vaccine antigens expressed on merozoites and sporozoites. This investigation was performed to evaluate simultaneously the naturally-acquired antibodies to PfAMA-1 and PfMSP-119 and to compare IgG subclass profiles to both antigens in naturally exposed individuals living in malaria hypoendemic areas in Iran to determine which antigen has better ability to detect sero-positive individuals infected with P. falciparum. Methods In this investigation, 101 individuals from the malaria-endemic areas in Iran were examined. PfAMA-1 and PfMSP-119 were expressed in Escherichia coli, and IgG isotype composition of naturally acquired antibodies to the antigens (as single or in combination) was measured by ELISA assay. Results The result showed that 87.1% and 84.2% of the studied individuals had positive anti-PfAMA-1 and -PfMSP-119 IgG antibody responses, respectively, and the prevalence of responders did not differ significantly (P > 0.05). Moreover, IgG1 and IgG3 were predominant over IgG2 and IgG4 antibodies and the prevalence of IgG and its subclasses to two tested antigens had no significant correlation with age and exposure (P > 0.05). The present data confirmed that when recombinant PfAMA-1 and recombinant PfMSP-119 antigens were combined in ELISA at equal ratios of 200 ng (100 ng each antigen/well) and 400 ng (200 ng each antigen/well), 86.1% and 87.1% of positives sera were detected among the examined samples, respectively. Conclusions The two tested recombinant antigens are immunogenic molecules, and individuals in low transmission areas in Iran could develop and maintain equal immune responses to PfAMA-1 and PfMSP-119. Therefore, these results could support the design of a universal PfAMA-1- and PfMSP-119-based vaccine. Also, both recombinant antigens could be used in combination as reliable serology markers to perform immuno-epidemiological studies in malaria-endemic areas of Iran during elimination strategy. The present information could be of use in control and elimination programmes in Iran and other similar malaria settings.
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Affiliation(s)
- Maryam Rouhani
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
| | - Akram A Mehrizi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
| | - Navid D Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Pasteur Avenue, P.O. BOX 1316943551, Tehran, Iran.
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12
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Boes A, Spiegel H, Edgue G, Kapelski S, Scheuermayer M, Fendel R, Remarque E, Altmann F, Maresch D, Reimann A, Pradel G, Schillberg S, Fischer R. Detailed functional characterization of glycosylated and nonglycosylated variants of malaria vaccine candidate PfAMA1 produced in Nicotiana benthamiana and analysis of growth inhibitory responses in rabbits. PLANT BIOTECHNOLOGY JOURNAL 2015; 13:222-34. [PMID: 25236489 DOI: 10.1111/pbi.12255] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 08/07/2014] [Accepted: 08/10/2014] [Indexed: 06/03/2023]
Abstract
One of the most promising malaria vaccine candidate antigens is the Plasmodium falciparum apical membrane antigen 1 (PfAMA1). Several studies have shown that this blood-stage antigen can induce strong parasite growth inhibitory antibody responses. PfAMA1 contains up to six recognition sites for N-linked glycosylation, a post-translational modification that is absent in P. falciparum. To prevent any potential negative impact of N-glycosylation, the recognition sites have been knocked out in most PfAMA1 variants expressed in eukaryotic hosts. However, N-linked glycosylation may increase efficacy by improving immunogenicity and/or focusing the response towards relevant epitopes by glycan masking. We describe the production of glycosylated and nonglycosylated PfAMA1 in Nicotiana benthamiana and its detailed characterization in terms of yield, integrity and protective efficacy. Both PfAMA1 variants accumulated to high levels (>510 μg/g fresh leaf weight) after transient expression, and high-mannose-type N-glycans were confirmed for the glycosylated variant. No significant differences between the N. benthamiana and Pichia pastoris PfAMA1 variants were detected in conformation-sensitive ligand-binding studies. Specific titres of >2 × 10(6) were induced in rabbits, and strong reactivity with P. falciparum schizonts was observed in immunofluorescence assays, as well as up to 100% parasite growth inhibition for both variants, with IC₅₀ values of ~35 μg/mL. Competition assays indicated that a number of epitopes were shielded from immune recognition by N-glycans, warranting further studies to determine how glycosylation can be used for the directed targeting of immune responses. These results highlight the potential of plant transient expression systems as a production platform for vaccine candidates.
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Affiliation(s)
- Alexander Boes
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
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13
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Lauron EJ, Oakgrove KS, Tell LA, Biskar K, Roy SW, Sehgal RNM. Transcriptome sequencing and analysis of Plasmodium gallinaceum reveals polymorphisms and selection on the apical membrane antigen-1. Malar J 2014; 13:382. [PMID: 25261185 PMCID: PMC4182871 DOI: 10.1186/1475-2875-13-382] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/17/2014] [Indexed: 11/15/2022] Open
Abstract
Background Plasmodium erythrocyte invasion genes play a key role in malaria parasite transmission, host-specificity and immuno-evasion. However, the evolution of the genes responsible remains understudied. Investigating these genes in avian malaria parasites, where diversity is particularly high, offers new insights into the processes that confer malaria pathogenesis. These parasites can pose a significant threat to birds and since birds play crucial ecological roles they serve as important models for disease dynamics. Comprehensive knowledge of the genetic factors involved in avian malaria parasite invasion is lacking and has been hampered by difficulties in obtaining nuclear data from avian malaria parasites. Thus the first Illumina-based de novo transcriptome sequencing and analysis of the chicken parasite Plasmodium gallinaceum was performed to assess the evolution of essential Plasmodium genes. Methods White leghorn chickens were inoculated intravenously with erythrocytes containing P. gallinaceum. cDNA libraries were prepared from RNA extracts collected from infected chick blood and sequencing was run on the HiSeq2000 platform. Orthologues identified by transcriptome sequencing were characterized using phylogenetic, ab initio protein modelling and comparative and population-based methods. Results Analysis of the transcriptome identified several orthologues required for intra-erythrocytic survival and erythrocyte invasion, including the rhoptry neck protein 2 (RON2) and the apical membrane antigen-1 (AMA-1). Ama-1 of avian malaria parasites exhibits high levels of genetic diversity and evolves under positive diversifying selection, ostensibly due to protective host immune responses. Conclusion Erythrocyte invasion by Plasmodium parasites require AMA-1 and RON2 interactions. AMA-1 and RON2 of P. gallinaceum are evolutionarily and structurally conserved, suggesting that these proteins may play essential roles for avian malaria parasites to invade host erythrocytes. In addition, host-driven selection presumably results in the high levels of genetic variation found in ama-1 of avian Plasmodium species. These findings have implications for investigating avian malaria epidemiology and population dynamics. Moreover, this work highlights the P. gallinaceum transcriptome as an important public resource for investigating the diversity and evolution of essential Plasmodium genes. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-382) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elvin J Lauron
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA.
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14
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Bargieri DY, Andenmatten N, Lagal V, Thiberge S, Whitelaw JA, Tardieux I, Meissner M, Ménard R. Apical membrane antigen 1 mediates apicomplexan parasite attachment but is dispensable for host cell invasion. Nat Commun 2014; 4:2552. [PMID: 24108241 PMCID: PMC3826631 DOI: 10.1038/ncomms3552] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 09/03/2013] [Indexed: 11/19/2022] Open
Abstract
Apicomplexan parasites invade host cells by forming a ring-like junction with the cell surface and actively sliding through the junction inside an intracellular vacuole. Apical membrane antigen 1 is conserved in apicomplexans and a long-standing malaria vaccine candidate. It is considered to have multiple important roles during host cell penetration, primarily in structuring the junction by interacting with the rhoptry neck 2 protein and transducing the force generated by the parasite motor during internalization. Here, we generate Plasmodium sporozoites and merozoites and Toxoplasma tachyzoites lacking apical membrane antigen 1, and find that the latter two are impaired in host cell attachment but the three display normal host cell penetration through the junction. Therefore, apical membrane antigen 1, rather than an essential invasin, is a dispensable adhesin of apicomplexan zoites. These genetic data have implications on the use of apical membrane antigen 1 or the apical membrane antigen 1–rhoptry neck 2 interaction as targets of intervention strategies against malaria or other diseases caused by apicomplexans. Plasmodium and Toxoplasma apical membrane antigen 1 (AMA1) is believed to be actively involved in host cell invasion by these parasites. Bargieri et al. now demonstrate that although AMA1 facilitates adhesion, invasion can proceed in the absence of the protein.
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Affiliation(s)
- Daniel Y Bargieri
- 1] Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, 28 Rue du Dr Roux, Paris, France [2]
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15
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Kuesap J, Chaijaroenkul W, Ketprathum K, Tattiyapong P, Na-Bangchang K. Evolution of genetic polymorphisms of Plasmodium falciparum merozoite surface protein (PfMSP) in Thailand. THE KOREAN JOURNAL OF PARASITOLOGY 2014; 52:105-9. [PMID: 24623892 PMCID: PMC3948986 DOI: 10.3347/kjp.2014.52.1.105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/30/2013] [Accepted: 11/12/2013] [Indexed: 11/23/2022]
Abstract
Plasmodium falciparum malaria is a major public health problem in Thailand due to the emergence of multidrug resistance. The understanding of genetic diversity of malaria parasites is essential for developing effective drugs and vaccines. The genetic diversity of the merozoite surface protein-1 (PfMSP-1) and merozoite surface protein-2 (PfMSP-2) genes was investigated in a total of 145 P. falciparum isolates collected from Mae Sot District, Tak Province, Thailand during 3 different periods (1997-1999, 2005-2007, and 2009-2010). Analysis of genetic polymorphisms was performed to track the evolution of genetic change of P. falciparum using PCR. Both individual genes and their combination patterns showed marked genetic diversity during the 3 study periods. The results strongly support that P. falciparum isolates in Thailand are markedly diverse and patterns changed with time. These 2 polymorphic genes could be used as molecular markers to detect multiple clone infections and differentiate recrudescence from reinfection in P. falciparum isolates in Thailand.
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Affiliation(s)
- Jiraporn Kuesap
- Faculty of Allied Health Sciences, Thammasat University, Pathumthani, 12121, Thailand
| | - Wanna Chaijaroenkul
- Faculty of Allied Health Sciences, Thammasat University, Pathumthani, 12121, Thailand
| | - Kanchanok Ketprathum
- Faculty of Allied Health Sciences, Thammasat University, Pathumthani, 12121, Thailand
| | - Puntanat Tattiyapong
- Faculty of Allied Health Sciences, Thammasat University, Pathumthani, 12121, Thailand
| | - Kesara Na-Bangchang
- Chulabhorn International College of Medicine, Thammasat University, Pathumthani, 12121, Thailand
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16
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Immunization with apical membrane antigen 1 confers sterile infection-blocking immunity against Plasmodium sporozoite challenge in a rodent model. Infect Immun 2013; 81:3586-99. [PMID: 23836827 DOI: 10.1128/iai.00544-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Apical membrane antigen 1 (AMA-1) is a leading blood-stage malaria vaccine candidate. Consistent with a key role in erythrocytic invasion, AMA-1-specific antibodies have been implicated in AMA-1-induced protective immunity. AMA-1 is also expressed in sporozoites and in mature liver schizonts where it may be a target of protective cell-mediated immunity. Here, we demonstrate for the first time that immunization with AMA-1 can induce sterile infection-blocking immunity against Plasmodium sporozoite challenge in 80% of immunized mice. Significantly higher levels of gamma interferon (IFN-γ)/interleukin-2 (IL-2)/tumor necrosis factor (TNF) multifunctional T cells were noted in immunized mice than in control mice. We also report the first identification of minimal CD8(+) and CD4(+) T cell epitopes on Plasmodium yoelii AMA-1. These data establish AMA-1 as a target of both preerythrocytic- and erythrocytic-stage protective immune responses and validate vaccine approaches designed to induce both cellular and humoral immunity.
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17
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Drew DR, Hodder AN, Wilson DW, Foley M, Mueller I, Siba PM, Dent AE, Cowman AF, Beeson JG. Defining the antigenic diversity of Plasmodium falciparum apical membrane antigen 1 and the requirements for a multi-allele vaccine against malaria. PLoS One 2012; 7:e51023. [PMID: 23227229 PMCID: PMC3515520 DOI: 10.1371/journal.pone.0051023] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 10/29/2012] [Indexed: 11/19/2022] Open
Abstract
Apical Membrane Antigen 1 (AMA1) is a leading malaria vaccine candidate and a target of naturally-acquired human immunity. Plasmodium falciparum AMA1 is polymorphic and in vaccine trials it induces strain-specific protection. This antigenic diversity is a major roadblock to development of AMA1 as a malaria vaccine and understanding how to overcome it is essential. To assess how AMA1 antigenic diversity limits cross-strain growth inhibition, we assembled a panel of 18 different P. falciparum isolates which are broadly representative of global AMA1 sequence diversity. Antibodies raised against four well studied AMA1 alleles (W2Mef, 3D7, HB3 and FVO) were tested for growth inhibition of the 18 different P. falciparum isolates in growth inhibition assays (GIA). All antibodies demonstrated substantial cross-inhibitory activity against different isolates and a mixture of the four different AMA1 antibodies inhibited all 18 isolates tested, suggesting significant antigenic overlap between AMA1 alleles and limited antigenic diversity of AMA1. Cross-strain inhibition by antibodies was only moderately and inconsistently correlated with the level of sequence diversity between AMA1 alleles, suggesting that sequence differences are not a strong predictor of antigenic differences or the cross-inhibitory activity of anti-allele antibodies. The importance of the highly polymorphic C1-L region for inhibitory antibodies and potential vaccine escape was assessed by generating novel transgenic P. falciparum lines for testing in GIA. While the polymorphic C1-L epitope was identified as a significant target of some growth-inhibitory antibodies, these antibodies only constituted a minor proportion of the total inhibitory antibody repertoire, suggesting that the antigenic diversity of inhibitory epitopes is limited. Our findings support the concept that a multi-allele AMA1 vaccine would give broad coverage against the diversity of AMA1 alleles and establish new tools to define polymorphisms important for vaccine escape.
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Affiliation(s)
- Damien R. Drew
- The Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Anthony N. Hodder
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Danny W. Wilson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | | | - Ivo Mueller
- The Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Peter M. Siba
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Arlene E. Dent
- Centre for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Alan F. Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - James G. Beeson
- The Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Microbiology, Monash University, Victoria, Australia
- * E-mail:
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18
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Dreyer AM, Matile H, Papastogiannidis P, Kamber J, Favuzza P, Voss TS, Wittlin S, Pluschke G. Passive Immunoprotection ofPlasmodium falciparum-Infected Mice Designates the CyRPA as Candidate Malaria Vaccine Antigen. THE JOURNAL OF IMMUNOLOGY 2012; 188:6225-37. [DOI: 10.4049/jimmunol.1103177] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Evidence for an increased risk of transmission of simian immunodeficiency virus and malaria in a rhesus macaque coinfection model. J Virol 2011; 85:11655-63. [PMID: 21917966 DOI: 10.1128/jvi.05644-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In sub-Saharan Africa, HIV-1 infection frequently occurs in the context of other coinfecting pathogens, most importantly, Mycobacterium tuberculosis and malaria parasites. The consequences are often devastating, resulting in enhanced morbidity and mortality. Due to the large number of confounding factors influencing pathogenesis in coinfected people, we sought to develop a nonhuman primate model of simian immunodeficiency virus (SIV)-malaria coinfection. In sub-Saharan Africa, Plasmodium falciparum is the most common malaria parasite and is responsible for most malaria-induced deaths. The simian malaria parasite Plasmodium fragile can induce clinical symptoms, including cerebral malaria in rhesus macaques, that resemble those of P. falciparum infection in humans. Thus, based on the well-characterized rhesus macaque model of SIV infection, this study reports the development of a novel rhesus macaque SIV-P. fragile coinfection model to study human HIV-P. falciparum coinfection. Using this model, we show that coinfection is associated with an increased, although transient, risk of both HIV and malaria transmission. Specifically, SIV-P. fragile coinfected macaques experienced an increase in SIV viremia that was temporarily associated with an increase in potential SIV target cells and systemic immune activation during acute parasitemia. Conversely, primary parasitemia in SIV-P. fragile coinfected animals resulted in higher gametocytemia that subsequently translated into higher oocyst development in mosquitoes. To our knowledge, this is the first animal model able to recapitulate the increased transmission risk of both HIV and malaria in coinfected humans. Therefore, this model could serve as an essential tool to elucidate distinct immunological, virological, and/or parasitological parameters underlying disease exacerbation in HIV-malaria coinfected people.
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20
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Bouillet LÉM, Dias MO, Dorigo NA, Moura AD, Russell B, Nosten F, Renia L, Braga ÉM, Gazzinelli RT, Rodrigues MM, Soares IS, Bruna-Romero O. Long-term humoral and cellular immune responses elicited by a heterologous Plasmodium vivax apical membrane antigen 1 protein prime/adenovirus boost immunization protocol. Infect Immun 2011; 79:3642-52. [PMID: 21730090 PMCID: PMC3165491 DOI: 10.1128/iai.05048-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 06/10/2011] [Indexed: 12/26/2022] Open
Abstract
Apical membrane antigen 1 (AMA-1) is an invasion-related Plasmodium antigen that is expressed during both intracellular and extracellular asexual stages of the parasite's life cycle, making it an ideal target for induction of humoral and cellular immune responses that can protect against malaria. We show here that when it is administered as a recombinant protein (P) in Montanide ISA720 adjuvant, followed by a recombinant human type 5 adenovirus (Ad), intense and long-lasting Plasmodium vivax AMA-1-specific antibody responses (including both IgG1 and IgG2a), as well as proliferative memory T cell responses, can be detected in immunized mice. Memory T cells displayed both central (CD44(hi) CD62L(hi)) and effector (CD44(hi) CD62L(lo)) phenotypes, with the central memory phenotype prevailing (56% of AMA-1-specific proliferating cells). Considering the main traits of the memory immune responses induced against AMA-1, this particular sequence of immunogens (P followed by Ad), but no others (Ad/Ad, Ad/P, or P/P), displayed an optimal synergistic effect. These results give further support to the need for preclinical studies of P. vivax vaccine candidate AMA-1 administered in prime/boost protocols that include recombinant proteins and adenoviral vectors.
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MESH Headings
- Adenoviridae
- Adjuvants, Immunologic
- Animals
- Antibodies, Protozoan/biosynthesis
- Antibodies, Protozoan/immunology
- Antigens, Protozoan/immunology
- Cytokines/biosynthesis
- Enzyme-Linked Immunosorbent Assay
- Female
- Hyaluronan Receptors/biosynthesis
- Immunity, Cellular
- Immunity, Humoral
- Immunization
- Immunization, Secondary
- Immunologic Memory
- L-Selectin/biosynthesis
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/immunology
- Malaria, Vivax/immunology
- Malaria, Vivax/prevention & control
- Mannitol/administration & dosage
- Mannitol/analogs & derivatives
- Mannitol/immunology
- Mice
- Mice, Inbred BALB C
- Oleic Acids/administration & dosage
- Oleic Acids/immunology
- Plasmodium vivax/immunology
- Protozoan Proteins/immunology
- Recombinant Proteins/administration & dosage
- Recombinant Proteins/immunology
- T-Lymphocytes/immunology
- Vaccines, Synthetic/immunology
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Affiliation(s)
| | | | | | | | - Bruce Russell
- Singapore Immunology Network, Biopolis, Agency for Science Technology and Research, Singapore
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mae Sot, Tak, Thailand
- Center for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, United Kingdom
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Laurent Renia
- Singapore Immunology Network, Biopolis, Agency for Science Technology and Research, Singapore
| | | | - Ricardo Tostes Gazzinelli
- Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil
- René Rachou Research Center, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | - Maurício M. Rodrigues
- Department of Clinical Analyses and Toxicology, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Irene S. Soares
- Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo, São Paulo, Brazil
| | - Oscar Bruna-Romero
- Departments of Microbiology
- René Rachou Research Center, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
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21
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Kusi KA, Remarque EJ, Riasat V, Walraven V, Thomas AW, Faber BW, Kocken CHM. Safety and immunogenicity of multi-antigen AMA1-based vaccines formulated with CoVaccine HT™ and Montanide ISA 51 in rhesus macaques. Malar J 2011; 10:182. [PMID: 21726452 PMCID: PMC3142537 DOI: 10.1186/1475-2875-10-182] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 07/04/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Increasing the breadth of the functional antibody response through immunization with Plasmodium falciparum apical membrane antigen 1 (PfAMA1) multi-allele vaccine formulations has been demonstrated in several rodent and rabbit studies. This study assesses the safety and immunogenicity of three PfAMA1 Diversity-Covering (DiCo) vaccine candidates formulated as an equimolar mixture (DiCo mix) in CoVaccine HT™ or Montanide ISA 51, as well as that of a PfAMA1-MSP1₁₉ fusion protein formulated in Montanide ISA 51. METHODS Vaccine safety in rhesus macaques was monitored by animal behaviour observation and assessment of organ and systemic functions through clinical chemistry and haematology measurements. The immunogenicity of vaccine formulations was assessed by enzyme-linked immunosorbent assays and in vitro parasite growth inhibition assays with three culture-adapted P. falciparum strains. RESULTS These data show that both adjuvants were well tolerated with only transient changes in a few of the chemical and haematological parameters measured. DiCo mix formulated in CoVaccine HT™ proved immunologically and functionally superior to the same candidate formulated in Montanide ISA 51. Immunological data from the fusion protein candidate was however difficult to interpret as four out of six immunized animals were non-responsive for unknown reasons. CONCLUSIONS The study highlights the safety and immunological benefits of DiCo mix as a potential human vaccine against blood stage malaria, especially when formulated in CoVaccine HT™, and adds to the accumulating data on the specificity broadening effects of DiCo mix.
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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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Identification of a highly antigenic linear B cell epitope within Plasmodium vivax apical membrane antigen 1 (AMA-1). PLoS One 2011; 6:e21289. [PMID: 21713006 PMCID: PMC3119695 DOI: 10.1371/journal.pone.0021289] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/25/2011] [Indexed: 12/21/2022] Open
Abstract
Apical membrane antigen 1 (AMA-1) is considered to be a major candidate antigen for a malaria vaccine. Previous immunoepidemiological studies of naturally acquired immunity to Plasmodium vivax AMA-1 (PvAMA-1) have shown a higher prevalence of specific antibodies to domain II (DII) of AMA-1. In the present study, we confirmed that specific antibody responses from naturally infected individuals were highly reactive to both full-length AMA-1 and DII. Also, we demonstrated a strong association between AMA-1 and DII IgG and IgG subclass responses. We analyzed the primary sequence of PvAMA-1 for B cell linear epitopes co-occurring with intrinsically unstructured/disordered regions (IURs). The B cell epitope comprising the amino acid sequence 290–307 of PvAMA-1 (SASDQPTQYEEEMTDYQK), with the highest prediction scores, was identified in domain II and further selected for chemical synthesis and immunological testing. The antigenicity of the synthetic peptide was identified by serological analysis using sera from P. vivax-infected individuals who were knowingly reactive to the PvAMA-1 ectodomain only, domain II only, or reactive to both antigens. Although the synthetic peptide was recognized by all serum samples specific to domain II, serum with reactivity only to the full-length protein presented 58.3% positivity. Moreover, IgG reactivity against PvAMA-1 and domain II after depletion of specific synthetic peptide antibodies was reduced by 18% and 33% (P = 0.0001 for both), respectively. These results suggest that the linear epitope SASDQPTQYEEEMTDYQK is highly antigenic during natural human infections and is an important antigenic region of the domain II of PvAMA-1, suggesting its possible future use in pre-clinical studies.
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Mahdi Abdel Hamid M, Remarque EJ, van Duivenvoorde LM, van der Werff N, Walraven V, Faber BW, Kocken CHM, Thomas AW. Vaccination with Plasmodium knowlesi AMA1 formulated in the novel adjuvant co-vaccine HT™ protects against blood-stage challenge in rhesus macaques. PLoS One 2011; 6:e20547. [PMID: 21655233 PMCID: PMC3105089 DOI: 10.1371/journal.pone.0020547] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 05/03/2011] [Indexed: 02/03/2023] Open
Abstract
Plasmodium falciparum apical membrane antigen 1 (PfAMA1) is a leading blood stage vaccine candidate. Plasmodium knowlesi AMA1 (PkAMA1) was produced and purified using similar methodology as for clinical grade PfAMA1 yielding a pure, conformational intact protein. Combined with the adjuvant CoVaccine HT™, PkAMA1 was found to be highly immunogenic in rabbits and the efficacy of the PkAMA1 was subsequently tested in a rhesus macaque blood-stage challenge model. Six rhesus monkeys were vaccinated with PkAMA1 and a control group of 6 were vaccinated with PfAMA1. A total of 50 µg AMA1 was administered intramuscularly three times at 4 week intervals. One of six rhesus monkeys vaccinated with PkAMA1 was able to control parasitaemia, upon blood stage challenge with P. knowlesi H-strain. Four out of the remaining five showed a delay in parasite onset that correlated with functional antibody titres. In the PfAMA1 vaccinated control group, five out of six animals had to be treated with antimalarials 8 days after challenge; one animal did not become patent during the challenge period. Following a rest period, animals were boosted and challenged again. Four of the six rhesus monkeys vaccinated with PkAMA1 were able to control the parasitaemia, one had a delayed onset of parasitaemia and one animal was not protected, while all control animals required treatment. To confirm that the control of parasitaemia was AMA1-related, animals were allowed to recover, boosted and re-challenged with P. knowlesi Nuri strain. All control animals had to be treated with antimalarials by day 8, while five out of six PkAMA1 vaccinated animals were able to control parasitaemia. This study shows that: i) Yeast-expressed PkAMA1 can protect against blood stage challenge; ii) Functional antibody levels as measured by GIA correlated inversely with the day of onset and iii) GIA IC50 values correlated with estimated in vivo growth rates.
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Affiliation(s)
| | - Edmond J. Remarque
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
- * E-mail:
| | | | - Nicole van der Werff
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Vanessa Walraven
- 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
| | - Alan W. Thomas
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
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Lee EF, Yao S, Sabo JK, Fairlie WD, Stevenson RA, Harris KS, Anders RF, Foley M, Norton RS. Peptide inhibitors of the malaria surface protein, apical membrane antigen 1: identification of key binding residues. Biopolymers 2011; 95:354-64. [PMID: 21213258 DOI: 10.1002/bip.21582] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Revised: 12/16/2010] [Accepted: 12/20/2010] [Indexed: 11/10/2022]
Abstract
Apical membrane antigen 1 (AMA1) is essential for malaria parasite invasion of erythrocytes and is therefore an attractive target for drug development. Peptides that bind AMA1 have been identified from random peptide libraries expressed on the surface of phage. Of these, R1, which binds to a hydrophobic ligand binding site on AMA1, was a particularly potent inhibitor of parasite invasion of erythrocytes in vitro. The solution structure of R1 contains a turn-like conformation between residues 5-10. Here the importance of residues in this turn-like structure for binding to AMA1 was examined by site-directed mutagenesis and NMR spectroscopy. The peptide was expressed as a fusion protein following replacement of Met16 by Leu in order to accommodate cyanogen bromide cleavage. This modified peptide (R2) displayed the same affinity for AMA1 as R1, showing that the identity of the side chain at position 16 was not critical for binding. Substitution of Phe5, Pro7, Leu8, and Phe9 with alanine led to significant (7.5- to >350-fold) decreases in affinity for AMA1. Comparison of backbone amide and C(α) H chemical shifts for these R2 analogues with corresponding values for R2 showed no significant changes, with the exception of R2(P7A), where slightly larger differences were observed, particularly for residues flanking position 7. The absence of significant changes in the secondary chemical shifts suggests that these mutations had little effect on the solution conformation of R2. The identification of a nonpolar region of these peptides containing residues essential for AMA1 binding establishes a basis for the design of anti-malarial drugs based on R1 mimetics.
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Affiliation(s)
- Erinna F Lee
- Structural Biology Division, The Walter & Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
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Kusi KA, Faber BW, Riasat V, Thomas AW, Kocken CHM, Remarque EJ. Generation of humoral immune responses to multi-allele PfAMA1 vaccines; effect of adjuvant and number of component alleles on the breadth of response. PLoS One 2010; 5:e15391. [PMID: 21082025 PMCID: PMC2972715 DOI: 10.1371/journal.pone.0015391] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 08/31/2010] [Indexed: 12/20/2022] Open
Abstract
There is increasing interest in multi-allele vaccines to overcome strain-specificity against polymorphic vaccine targets such as Apical Membrane Antigen 1 (AMA1). These have been shown to induce broad inhibitory antibodies in vitro and formed the basis for the design of three Diversity-Covering (DiCo) proteins with similar immunological effects. The antibodies produced are to epitopes that are shared between vaccine alleles and theoretically, increasing the number of component AMA1 alleles is expected to broaden the antibody response. A plateau effect could however impose a limit on the number of alleles needed to achieve the broadest specificity. Moreover, production cost and the vaccine formulation process would limit the number of component alleles. In this paper, we compare rabbit antibody responses elicited with multi-allele vaccines incorporating seven (three DiCos and four natural AMA1 alleles) and three (DiCo mix) antigens for gains in broadened specificity. We also investigate the effect of three adjuvant platforms on antigen specificity and antibody functionality. Our data confirms a broadened response after immunisation with DiCo mix in all three adjuvants. Higher antibody titres were elicited with either CoVaccine HT™ or Montanide ISA 51, resulting in similar in vitro inhibition (65–82%) of five out of six culture-adapted P. falciparum strains. The antigen binding specificities of elicited antibodies were also similar and independent of the adjuvant used or the number of vaccine component alleles. Thus neither the four extra antigens nor adjuvant had any observable benefits with respect to specificity broadening, although adjuvant choice influenced the absolute antibody levels and thus the extent of parasite inhibition. Our data confirms the feasibility and potential of multi-allele PfAMA1 formulations, and highlights the need for adjuvants with improved antibody potentiation properties for AMA1-based vaccines.
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Affiliation(s)
- Kwadwo A. Kusi
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Bart W. Faber
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Vanessa Riasat
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Alan W. Thomas
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Clemens H. M. Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Edmond J. Remarque
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
- * E-mail:
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Peng H, Hu Y, Zhou A, Jin C, Pan W. Solution structure of a Plasmodium falciparum AMA-1/MSP 1 chimeric protein vaccine candidate (PfCP-2.9) for malaria. Malar J 2010; 9:76. [PMID: 20236549 PMCID: PMC2850360 DOI: 10.1186/1475-2875-9-76] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 03/18/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Plasmodium falciparum chimeric protein PfCP-2.9 is a promising asexual-stage malaria vaccine evaluated in clinical trials. This chimeric protein consists of two cysteine-rich domains: domain III of the apical membrane antigen 1 (AMA-1 [III]) and the C-terminal region of the merozoite surface protein 1 (MSP1-19). It has been reported that the fusion of these two antigens enhanced their immunogenicity and antibody-mediated inhibition of parasite growth in vitro. METHODS The 15N-labeled and 13C/15N-labeled PfCP-2.9 was produced in Pichia pastoris for nuclear magnetic resonance (NMR) structure analysis. The chemical shift assignments of PfCP-2.9 were compared with those previously reported for the individual domains (i.e., PfAMA-1(III) or PfMSP 1-19). The two-dimensional spectra and transverse relaxation rates (R2) of the PfMSP1-19 alone were compared with that of the PfCP-2.9. RESULTS Confident backbone assignments were obtained for 122 out of 241 residues of PfCP-2.9. The assigned residues in PfCP-2.9 were very similar to those previously reported for the individual domains. The conformation of the PfMSP1-19 in different constructs is essentially the same. Comparison of transverse relaxation rates (R2) strongly suggests no weak interaction between the domains. CONCLUSIONS These data indicate that the fusion of AMA-1(III) and MSP1-19 as chimeric protein did not change their structures, supporting the use of the chimeric protein as a potential malaria vaccine.
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Affiliation(s)
- Heng Peng
- Department of Pathogenic Biology, State Key Laboratory of Medical Immunology, Second Military Medical University, Shanghai 200433, China
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Dutta S, Sullivan JS, Grady KK, Haynes JD, Komisar J, Batchelor AH, Soisson L, Diggs CL, Heppner DG, Lanar DE, Collins WE, Barnwell JW. High antibody titer against apical membrane antigen-1 is required to protect against malaria in the Aotus model. PLoS One 2009; 4:e8138. [PMID: 19997632 PMCID: PMC2780715 DOI: 10.1371/journal.pone.0008138] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 10/23/2009] [Indexed: 11/19/2022] Open
Abstract
A Plasmodium falciparum 3D7 strain Apical Membrane Antigen-1 (AMA1) vaccine, formulated with AS02A adjuvant, slowed parasite growth in a recent Phase 1/2a trial, however sterile protection was not observed. We tested this AS02A, and a Montanide ISA720 (ISA) formulation of 3D7 AMA1 in Aotus monkeys. The 3D7 parasite does not invade Aotus erythrocytes, hence two heterologous strains, FCH/4 and FVO, were used for challenge, FCH/4 AMA1 being more homologous to 3D7 than FVO AMA1. Following three vaccinations, the monkeys were challenged with 50,000 FCH/4 or 10,000 FVO parasites. Three of the six animals in the AMA+ISA group were protected against FCH/4 challenge. One monkey did not become parasitemic, another showed only a short period of low level parasitemia that self-cured, and a third animal showed a delay before exhibiting its parasitemic phase. This is the first protection shown in primates with a recombinant P. falciparum AMA1 without formulation in Freund's complete adjuvant. No animals in the AMA+AS02A group were protected, but this group exhibited a trend towards reduced growth rate. A second group of monkeys vaccinated with AMA+ISA vaccine was not protected against FVO challenge, suggesting strain-specificity of AMA1-based protection. Protection against FCH/4 strain correlated with the quantity of induced antibodies, as the protected animals were the only ones to have in vitro parasite growth inhibitory activity of >70% at 1∶10 serum dilution; immuno-fluorescence titers >8,000; ELISA titers against full-length AMA1 >300,000 and ELISA titer against AMA1 domains1+2 >100,000. A negative correlation between log ELISA titer and day 11 cumulative parasitemia (Spearman rank r = −0.780, p value = 0.0001), further confirmed the relationship between antibody titer and protection. High titers of cross-strain inhibitory antibodies against AMA1 are therefore critical to confer solid protection, and the Aotus model can be used to down-select future AMA1 formulations, prior to advanced human trials.
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Affiliation(s)
- Sheetij Dutta
- Department of Epitope Mapping, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- * E-mail: (SD); (JWB)
| | - JoAnn S. Sullivan
- Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Katharine K. Grady
- Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - J. David Haynes
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Jack Komisar
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Adrian H. Batchelor
- Department of Epitope Mapping, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Lorraine Soisson
- Malaria Vaccine Development Program, United States Agency for International Development, Washington, D. C., United States of America
| | - Carter L. Diggs
- Malaria Vaccine Development Program, United States Agency for International Development, Washington, D. C., United States of America
| | - D. Gray Heppner
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - David E. Lanar
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - William E. Collins
- Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - John W. Barnwell
- Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail: (SD); (JWB)
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Humoral immune response to mixed PfAMA1 alleles; multivalent PfAMA1 vaccines induce broad specificity. PLoS One 2009; 4:e8110. [PMID: 19956619 PMCID: PMC2779588 DOI: 10.1371/journal.pone.0008110] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 11/04/2009] [Indexed: 11/19/2022] Open
Abstract
Apical Membrane Antigen 1 (AMA1), a merozoite protein essential for red cell invasion, is a candidate malaria vaccine component. Immune responses to AMA1 can protect in experimental animal models and antibodies isolated from AMA1-vaccinated or malaria-exposed humans can inhibit parasite multiplication in vitro. The parasite is haploid in the vertebrate host and the genome contains a single copy of AMA1, yet on a population basis a number of AMA1 molecular surface residues are polymorphic, a property thought to be primarily as a result of selective immune pressure. After immunisation with AMA1, antibodies more effectively inhibit strains carrying homologous AMA1 genes, suggesting that polymorphism may compromise vaccine efficacy. Here, we analyse induction of broad strain inhibitory antibodies with a multi-allele Plasmodium falciparum AMA1 (PfAMA1) vaccine, and determine the relative importance of cross-reactive and strain-specific IgG fractions by competition ELISA and in vitro parasite growth inhibition assays. Immunisation of rabbits with a PfAMA1 allele mixture yielded an increased proportion of antibodies to epitopes common to all vaccine alleles, compared to single allele immunisation. Competition ELISA with the anti-PfAMA1 antibody fraction that is cross-reactive between FVO and 3D7 AMA1 alleles showed that over 80% of these common antibodies were shared with other PfAMA1 alleles. Furthermore, growth inhibition assays revealed that for any PfAMA1 allele (FVO or 3D7), the cross-reactive fraction alone, on basis of weight, had the same functional capacity on homologous parasites as the total affinity-purified IgGs (cross-reactive+strain-specific). By contrast, the strain-specific IgG fraction of either PfAMA1 allele showed slightly less inhibition of red cell invasion by homologous strains. Thus multi-allele immunisation relatively increases the levels of antibodies to common allele epitopes. This explains the broadened cross inhibition of diverse malaria parasites, and suggests multi-allele approaches warrant further clinical investigation.
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Takeo S, Arumugam TU, Torii M, Tsuboi T. Wheat germ cell-free technology for accelerating the malaria vaccine research. Expert Opin Drug Discov 2009; 4:1191-9. [DOI: 10.1517/17460440903369813] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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A randomized and controlled Phase 1 study of the safety and immunogenicity of the AMA1-C1/Alhydrogel + CPG 7909 vaccine for Plasmodium falciparum malaria in semi-immune Malian adults. Vaccine 2009; 27:7292-8. [PMID: 19874925 DOI: 10.1016/j.vaccine.2009.10.087] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 10/09/2009] [Accepted: 10/15/2009] [Indexed: 11/23/2022]
Abstract
A double blind, randomized and controlled Phase 1 clinical trial was conducted to assess the safety and immunogenicity in malaria-exposed adults of the Plasmodium falciparum blood stage vaccine candidate Apical Membrane Antigen 1-Combination 1 (AMA1-C1)/Alhydrogel with and without the novel adjuvant CPG 7909. Participants were healthy adults 18-45 years old living in the village of Donéguébougou, Mali. A total of 24 participants received 2 doses one month apart of either 80 microg AMA1-C1/Alhydrogel or 80 microg AMA1-C1/Alhydrogel + 564 microg CPG 7909. The study started in October 2007 and completed follow up in May 2008. Both vaccines were well tolerated, with only mild local adverse events and no systemic adverse events judged related to vaccination. The difference in antibody responses were over 2-fold higher in the group receiving CPG 7909 for all time points after second vaccination and the differences are statistically significant (all p<0.05). This is the first use of the novel adjuvant CPG 7909 in a malaria-exposed population.
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Bhat AA, Seth RK, Babu J, Biswas S, Rao DN. Induction of mucosal and systemic humoral immune responses in murine system by intranasal immunization with peptide antigens of P. vivax and CpG oligodeoxynucleotide (ODN) in microparticle delivery. Int Immunopharmacol 2009; 9:1197-208. [PMID: 19595793 DOI: 10.1016/j.intimp.2009.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 06/19/2009] [Accepted: 06/25/2009] [Indexed: 01/19/2023]
Abstract
In the present study we have investigated the immunomodulatory effects of two adjuvants, CpG 1826 (two copies of CpG motifs) and CpG 2006 (three copies of CpG motifs) to the five peptide antigens of Plasmodium vivax derived from circumsporozoite protein (CSP), merozoite surface protein-1 (MSP1#1, MSP1#23), apical membrane antigen-1 (AMA-1) and gametocyte surface antigen (Pvs24) in alum and microparticle formulations, using intramuscular and intranasal routes of immunization. Alum formulation without CpG ODN generated low serum IgG and IgA antibody titers and the predominant IgG isotypes were IgG1 but with the addition of CpG ODN (1826 or 2006), the antibody titers were increased by four fold with the predominance of IgG2a/2b isotypes. The SIgA peak titers in lung and intestinal washes were significantly increased with the intranasal mode of administration. Specific activity measurement was done to calculate for the accurate amounts of total serum IgG, IgA and SIgA in washes and showed direct correlation between antibody titer and its concentration. High titer anti-Pvs24 antibodies have significant inhibitory effects on parasite development in the mosquito midgut when tested in membrane feeding assays. The immunofluorescence results show that the peptide specific antisera reacted with the air-dried parasite antigens isolated from P. vivax patients. The present study demonstrates that intranasal route of immunization appears to be an alternate mode of inducing protective immunity in P. vivax malaria.
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Affiliation(s)
- Ajaz A Bhat
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
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Sagara I, Dicko A, Ellis RD, Fay MP, Diawara SI, Assadou MH, Sissoko MS, Kone M, Diallo AI, Saye R, Guindo MA, Kante O, Niambele MB, Miura K, Mullen GED, Pierce M, Martin LB, Dolo A, Diallo DA, Doumbo OK, Miller LH, Saul A. A randomized controlled phase 2 trial of the blood stage AMA1-C1/Alhydrogel malaria vaccine in children in Mali. Vaccine 2009; 27:3090-8. [PMID: 19428923 DOI: 10.1016/j.vaccine.2009.03.014] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 02/26/2009] [Accepted: 03/05/2009] [Indexed: 11/18/2022]
Abstract
A double blind, randomized, controlled Phase 2 clinical trial was conducted to assess the safety, immunogenicity, and biologic impact of the vaccine candidate Apical Membrane Antigen 1-Combination 1 (AMA1-C1), adjuvanted with Alhydrogel. Participants were healthy children 2-3 years old living in or near the village of Bancoumana, Mali. A total of 300 children received either the study vaccine or the comparator. No impact of vaccination was seen on the primary endpoint, the frequency of parasitemia measured as episodes >3000/microL/day at risk. There was a negative impact of vaccination on the hemoglobin level during clinical malaria, and mean incidence of hemoglobin <8.5 g/dL, in the direction of lower hemoglobin in the children who received AMA1-C1, although these differences were not significant after correction for multiple tests. These differences were not seen in the second year of transmission.
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Affiliation(s)
- Issaka Sagara
- Malaria Research and Training Center, Faculty of Medicine Pharmacy and Dentistry BP 1805 Bamako, University of Bamako, Mali, Malaysia.
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Reed ZH, Kieny MP, Engers H, Friede M, Chang S, Longacre S, Malhotra P, Pan W, Long C. Comparison of immunogenicity of five MSP1-based malaria vaccine candidate antigens in rabbits. Vaccine 2009; 27:1651-60. [DOI: 10.1016/j.vaccine.2008.10.093] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 10/21/2008] [Accepted: 10/27/2008] [Indexed: 10/21/2022]
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Lyke KE, Daou M, Diarra I, Kone A, Kouriba B, Thera MA, Dutta S, Lanar DE, Heppner DG, Doumbo OK, Plowe CV, Sztein MB. Cell-mediated immunity elicited by the blood stage malaria vaccine apical membrane antigen 1 in Malian adults: results of a Phase I randomized trial. Vaccine 2009; 27:2171-6. [PMID: 19356621 DOI: 10.1016/j.vaccine.2009.01.097] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 01/19/2009] [Accepted: 01/22/2009] [Indexed: 10/21/2022]
Abstract
The development of a safe and effective malaria vaccine is impeded by the complexity of the Plasmodium life cycle. A vaccine that elicits both cell-mediated and humoral immune responses might be needed for protection against this multistage parasitic infection. Apical membrane antigen 1 (AMA-1) plays a key role in erythrocytic invasion but is also expressed in sporozoites and in late stage liver schizonts, where it may provide a target of protective cell-mediated immunity (CMI). A Phase 1 trial of a vaccine consisting of recombinant AMA-1 protein and the Adjuvant system AS02A was conducted in 60 Malian adults aged 18-55 years who were randomized to receive either half-dose (25 microg/0.25 ml) or full dose (50 microg/0.5 ml) FMP2.1/AS02A or a control rabies vaccine. Interleukin 5 (IL-5) and interferon-gamma (IFN-gamma) production as evaluated by ELISpot and lymphocyte proliferation were measured after in vitro AMA-1 stimulation of peripheral blood mononuclear cells (PBMCs) collected on Days 0 and 90. Post-FMP2.1/AS02A immunization mean stimulation indices were significantly elevated as were the number of IL-5 spot forming cells (SFC)/10(6) PBMC, but no difference was noted in INF-gamma production between the AMA-1/AS02A vaccinated group and the rabies group. These results provide evidence that complex immune responses can be induced by this vaccination strategy and add further impetus for the continuing clinical evaluation of this vaccine.
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Affiliation(s)
- Kirsten E Lyke
- Center for Vaccine Development, University of Maryland, Baltimore, MD, United States.
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Miura K, Zhou H, Moretz SE, Diouf A, Thera MA, Dolo A, Doumbo O, Malkin E, Diemert D, Miller LH, Mullen GED, Long CA. Comparison of biological activity of human anti-apical membrane antigen-1 antibodies induced by natural infection and vaccination. THE JOURNAL OF IMMUNOLOGY 2009; 181:8776-83. [PMID: 19050299 DOI: 10.4049/jimmunol.181.12.8776] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Vaccines represent a significant potential means of decreasing global morbidity and mortality due to malaria. Clinical trials in the United States with Plasmodium falciparum Apical Membrane Antigen 1 (AMA1) showed that the vaccine induced biologically active Abs judged by an in vitro parasite growth inhibition assay (GIA). However, the same vaccine in Malian adults did not increase biological activity, although it elevated ELISA titers. Because GIA has been used to evaluate the biological activity of Abs induced by blood stage malarial vaccine candidates, we explored this discrepancy in this study. We affinity purified AMA1-specific Abs from both U.S. vaccinees and nonvaccinated individuals living in a malaria-endemic area of Mali and performed ELISA and GIA. Both AMA1-specifc Abs induced by vaccination (U.S.) and by natural infection (Mali) have comparable biological activity in GIA when the ELISA titer is normalized. However, a fraction of Malians' IgG that did not bind to AMA1 protein (Mali-non-AMA1 IgG) reduced the biological activity of the AMA1 Abs from U.S. vaccinees; in contrast, U.S.-non-AMA1 IgGs did not show a reduction of the biological activity. Further investigation revealed that the reduction was due to malaria-specific IgGs in the Mali-non-AMA1 IgGs. The fact that both U.S.- and Mali-AMA1-specific Abs showed comparable biological activity supports further development of AMA1-based vaccines. However, the reduction of biological activity of AMA1-specific Ab by other malaria-specific IgGs likely explains the limited effect on growth-inhibitory activity of Abs induced by AMA1 vaccination in Malian adults and may complicate efforts to develop a blood stage malaria vaccine.
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Affiliation(s)
- Kazutoyo Miura
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Harris KS, Casey JL, Coley AM, Karas JA, Sabo JK, Tan YY, Dolezal O, Norton RS, Hughes AB, Scanlon D, Foley M. Rapid optimization of a peptide inhibitor of malaria parasite invasion by comprehensive N-methyl scanning. J Biol Chem 2009; 284:9361-71. [PMID: 19164290 DOI: 10.1074/jbc.m808762200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apical membrane antigen 1 (AMA1) of the malaria parasite Plasmodium falciparum has been implicated in the invasion of host erythrocytes and is an important vaccine candidate. We have previously described a 20-residue peptide, R1, that binds to AMA1 and subsequently blocks parasite invasion. Because this peptide appears to target a site critical for AMA1 function, it represents an important lead compound for anti-malarial drug development. However, the effectiveness of this peptide inhibitor was limited to a subset of parasite isolates, indicating a requirement for broader strain specificity. Furthermore, a barrier to the utility of any peptide as a potential therapeutic is its susceptibility to rapid proteolytic degradation. In this study, we sought to improve the proteolytic stability and AMA1 binding properties of the R1 peptide by systematic methylation of backbone amides (N-methylation). The inclusion of a single N-methyl group in the R1 peptide backbone dramatically increased AMA1 affinity, bioactivity, and proteolytic stability without introducing global structural alterations. In addition, N-methylation of multiple R1 residues further improved these properties. Therefore, we have shown that modifications to a biologically active peptide can dramatically enhance activity. This approach could be applied to many lead peptides or peptide therapeutics to simultaneously optimize a number of parameters.
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Affiliation(s)
- Karen S Harris
- Department of Biochemistry, La Trobe University, Victoria 3086, Australia
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Prediction of merozoite surface protein 1 and apical membrane antigen 1 vaccine efficacies against Plasmodium chabaudi malaria based on prechallenge antibody responses. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 16:293-302. [PMID: 19116303 DOI: 10.1128/cvi.00230-08] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
For the development of blood-stage malaria vaccines, there is a clear need to establish in vitro measures of the antibody-mediated and the cell-mediated immune responses that correlate with protection. In this study, we focused on establishing correlates of antibody-mediated immunity induced by immunization with apical membrane antigen 1 (AMA1) and merozoite surface protein 1(42) (MSP1(42)) subunit vaccines. To do so, we exploited the Plasmodium chabaudi rodent model, with which we can immunize animals with both protective and nonprotective vaccine formulations and allow the parasitemia in the challenged animals to peak. Vaccine formulations were varied with regard to the antigen dose, the antigen conformation, and the adjuvant used. Prechallenge antibody responses were evaluated by enzyme-linked immunosorbent assay and were tested for a correlation with protection against nonlethal P. chabaudi malaria, as measured by a reduction in the peak level of parasitemia. The analysis showed that neither the isotype profile nor the avidity of vaccine-induced antibodies correlated with protective efficacy. However, high titers of antibodies directed against conformation-independent epitopes were associated with poor vaccine performance and may limit the effectiveness of protective antibodies that recognize conformation-dependent epitopes. We were able to predict the efficacies of the P. chabaudi AMA1 (PcAMA1) and P. chabaudi MSP1(42) (PcMSP1(42)) vaccines only when the prechallenge antibody titers to both refolded and reduced/alkylated antigens were considered in combination. The relative importance of these two measures of vaccine-induced responses as predictors of protection differed somewhat for the PcAMA1 and the PcMSP1(42) vaccines, a finding confirmed in our final immunization and challenge study. A similar approach to the evaluation of vaccine-induced antibody responses may be useful during clinical trials of Plasmodium falciparum AMA1 and MSP1(42) vaccines.
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Fernández Ruiz D, Dubben B, Saeftel M, Endl E, Deininger S, Hoerauf A, Specht S. Filarial infection induces protection against P. berghei liver stages in mice. Microbes Infect 2008; 11:172-80. [PMID: 19049828 DOI: 10.1016/j.micinf.2008.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Revised: 10/08/2008] [Accepted: 11/06/2008] [Indexed: 10/21/2022]
Abstract
Chronic helminth infections such as filariasis in human hosts can be life long, since parasites are equipped with a repertoire of immune evasion strategies. In many areas where helminths are prevalent, other infections such as malaria are co-endemic. It is still an ongoing debate, how one parasite alters immune responses against another. To dissect the relationships between two different parasites residing in the same host, we established a murine model of co-infection with the filarial nematode Litomosoides sigmodontis and the malaria parasite Plasmodium berghei (ANKA strain). We found that filarial infection of BALB/c mice leads to protection against a subsequent P. berghei sporozoite infection in one-third of co-infected mice, which did not develop blood-stage malaria. This finding did not correlate with adult worm loads, however it did correlate with the presence of microfilariae in blood. Interestingly, protection was abrogated in IL-10-deficient mice. Thus, murine filariasis, in particular when it is a patent infection, is able to modify the immunological balance to induce protection against an otherwise deadly Plasmodium infection and is therefore able to influence the course of malaria in favour of the host.
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Affiliation(s)
- Daniel Fernández Ruiz
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Sigmund Freud Strasse 25, 53105 Bonn, Germany
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Malkin E, Hu J, Li Z, Chen Z, Bi X, Reed Z, Dubovsky F, Liu J, Wang Q, Pan X, Chen T, Giersing B, Xu Y, Kang X, Gu J, Shen Q, Tucker K, Tierney E, Pan W, Long C, Cao Z. A phase 1 trial of PfCP2.9: an AMA1/MSP1 chimeric recombinant protein vaccine for Plasmodium falciparum malaria. Vaccine 2008; 26:6864-73. [PMID: 18930094 DOI: 10.1016/j.vaccine.2008.09.081] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 09/18/2008] [Accepted: 09/26/2008] [Indexed: 11/16/2022]
Abstract
Apical Membrane Antigen 1 (AMA1) and Merozoite Surface Protein 1 (MSP1) were produced as a recombinant fusion protein and formulated with the adjuvant Montanide ISA 720 with the aim of replicating the structure present in the parasite protein. A previous trial with this construct demonstrated the vaccine was safe and immunogenic but was associated with injection site reactogenicity. This Phase 1a dose-escalating, double blind, randomized, controlled trial of PfCP2.9/Montanide ISA 720 was conducted to evaluate alternative dose levels and vaccination schedules, with a pre-formulated vaccine that had undergone more in-depth and frequent quality control and stability analysis. The trial was conducted in seventy healthy Chinese malaria-naïve volunteers between January 2006 and January 2007. The objective was to assess the safety, reactogenicity and immunogenicity of 5, 20 and 50microg of PfCP2.9/ISA 720 under 2 different schedules. The most common adverse event was injection site tenderness (53%). The frequency and severity of adverse events was similar in both vaccination schedules. Antibody responses were induced and remained elevated throughout the study in volunteers receiving vaccine (p<0.001). Although high antibody titers as measured by ELISA to the PfCP2.9 immunogen were observed, biological function of these antibodies was not reflected by the in vitro inhibition of parasite growth, and there was limited recognition of fixed parasites in an immunofluorescence assay. At all three dose levels and both schedules, this formulation of PfCP2.9/ISA 720 is well tolerated, safe and immunogenic; however no functional activity against the parasite was observed.
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Barclay VC, Chan BHK, Anders RF, Read AF. Mixed allele malaria vaccines: host protection and within-host selection. Vaccine 2008; 26:6099-107. [PMID: 18804509 PMCID: PMC2674600 DOI: 10.1016/j.vaccine.2008.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 09/01/2008] [Accepted: 09/01/2008] [Indexed: 11/19/2022]
Abstract
Malaria parasites are frequently polymorphic at the antigenic targets of many candidate vaccines, presumably as a consequence of selection pressure from protective immune responses. Conventional wisdom is therefore that vaccines directed against a single variant could select for non-target variants, rendering the vaccine useless. Many people have argued that a solution is to develop vaccines containing the products of more than one variant of the target. However, we are unaware of any evidence that multi-allele vaccines better protect hosts against parasites or morbidity. Moreover, selection of antigen-variants is not the only evolution that could occur in response to vaccination. Increased virulence could also be favored if more aggressive strains are less well controlled by vaccine-induced immunity. Virulence and antigenic identity have been confounded in all studies so far, and so we do not know formally from any animal or human studies whether vaccine failure has been due to evasion of protective responses by variants at target epitopes, or whether vaccines are just less good at protecting against more aggressive strains. Using the rodent malaria model Plasmodium chabaudi and recombinant apical membrane antigen-1 (AMA-1), we tested whether a bi-allelic vaccine afforded greater protection from parasite infection and morbidity than did vaccination with the component alleles alone. We also tested the effect of mono- and bi-allelic vaccination on within-host selection of mixed P. chabaudi infections, and whether parasite virulence mediates pathogen titres in immunized hosts. We found that vaccination with the bi-allelic AMA-1 formulation did not afford the host greater protection from parasite infection or morbidity than did mono-allelic AMA-1 immunization. Mono-allelic immunization increased the frequency of heterologous clones in mixed clone infections. There was no evidence that any type of immunization regime favored virulence. A single AMA-1 variant is a component of candidate malaria vaccines current in human trials; our results suggest that adding extra AMA-1 alleles to these vaccines would not confer clinical benefits, but that that mono-allelic vaccines could alter AMA-1 allele frequencies in natural populations.
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Mullen GED, Ellis RD, Miura K, Malkin E, Nolan C, Hay M, Fay MP, Saul A, Zhu D, Rausch K, Moretz S, Zhou H, Long CA, Miller LH, Treanor J. Phase 1 trial of AMA1-C1/Alhydrogel plus CPG 7909: an asexual blood-stage vaccine for Plasmodium falciparum malaria. PLoS One 2008; 3:e2940. [PMID: 18698359 PMCID: PMC2491586 DOI: 10.1371/journal.pone.0002940] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 07/14/2008] [Indexed: 11/18/2022] Open
Abstract
Background Apical Membrane Antigen 1 (AMA1), a polymorphic merozoite surface protein, is a leading blood-stage malaria vaccine candidate. This is the first reported use in humans of an investigational vaccine, AMA1-C1/Alhydrogel, with the novel adjuvant CPG 7909. Methods A phase 1 trial was conducted at the University of Rochester with 75 malaria-naive volunteers to assess the safety and immunogenicity of the AMA1-C1/Alhydrogel+CPG 7909 malaria vaccine. Participants were sequentially enrolled and randomized within dose escalating cohorts to receive three vaccinations on days 0, 28 and 56 of either 20 µg of AMA1-C1/Alhydrogel®+564 µg CPG 7909 (n = 15), 80 µg of AMA1-C1/Alhydrogel® (n = 30), or 80 µg of AMA1-C1/Alhydrogel+564 µg CPG 7909 (n = 30). Results Local and systemic adverse events were significantly more likely to be of higher severity with the addition of CPG 7909. Anti-AMA1 immunoglobulin G (IgG) were detected by enzyme-linked immunosorbent assay (ELISA), and the immune sera of volunteers that received 20 µg or 80 µg of AMA1-C1/Alhydrogel+CPG 7909 had up to 14 fold significant increases in anti-AMA1 antibody concentration compared to 80 µg of AMA1-C1/Alhydrogel alone. The addition of CPG 7909 to the AMA1-C1/Alhydrogel vaccine in humans also elicited AMA1 specific immune IgG that significantly and dramatically increased the in vitro growth inhibition of homologous parasites to levels as high as 96% inhibition. Conclusion/Significance The safety profile of the AMA1-C1/Alhydrogel+CPG 7909 malaria vaccine is acceptable, given the significant increase in immunogenicity observed. Further clinical development is ongoing. Trial Registration ClinicalTrials.gov NCT00344539
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Affiliation(s)
- Gregory E. D. Mullen
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail: (GEDM); (RDE)
| | - Ruth D. Ellis
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail: (GEDM); (RDE)
| | - Kazutoyo Miura
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Elissa Malkin
- PATH Malaria Vaccine Initiative, Bethesda, Maryland, United States of America
| | - Caroline Nolan
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
| | - Mhorag Hay
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
| | - Michael P. Fay
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Allan Saul
- Novartis Vaccines Institute for Global Health S.r.l. (NVGH), Siena, Italy
| | - Daming Zhu
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Kelly Rausch
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Samuel Moretz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Hong Zhou
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Louis H. Miller
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - John Treanor
- Department of Medicine, University of Rochester, Rochester, New York, United States of America
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Lalitha PV, Biswas S, Pillai CR, Saxena RK. Immunogenicity of a recombinant malaria vaccine candidate, domain I+II of AMA-1 ectodomain, from Indian P. falciparum alleles. Vaccine 2008; 26:4526-35. [PMID: 18590786 DOI: 10.1016/j.vaccine.2008.06.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 05/21/2008] [Accepted: 06/11/2008] [Indexed: 11/28/2022]
Abstract
Among the few vaccine candidates under development, apical membrane antigen (AMA-1) of Plasmodium falciparum is one of the most promising erythrocyte stage malaria vaccine candidates under consideration. The overall structure of AMA-1 appears to be conserved as compared to other surface proteins, but there are numerous amino acid substitutions identified among different P. falciparum isolates. Antisera raised against recombinant AMA-1 or naturally acquired human antibodies were strongly inhibitory only towards homologous parasites. In an attempt to examine the strain specificity of antibodies elicited to AMA-1, we have cloned, expressed and purified two allelic variants of domain I+II of AMA-1 ectodomain from Indian P. falciparum isolates in bacteria. One of these is a new haplotype not reported so far and varies in 18 aa positions from the geographically diverse forms 3D7 and 15 from FVO. Refolded proteins were recognized by a conformation specific monoclonal antibody 4G2.dc1 and hyper immune sera. Immunization of mice and rabbits with the purified proteins using CFA/IFA adjuvant generated high titer polyclonal antibodies. Both the alleles induced high levels of IgG1, IgG2a and IgG2b and a low level of IgG3 in mice. Lymphocyte proliferation assays using splenocytes from immunized mice showed significant proliferative responses and cytokines interleukin-2 (IL-2), IL-4, IL-10 and IFN-gamma presence in the culture supernatants. The anti-AMA-1 rabbit antibodies obtained with both the proteins were active in an in vitro parasite growth invasion/inhibition assay. These results suggest that recombinant AMA-1 domain I+II formulated with CFA/IFA adjuvant elicited cellular and humoral responses and is capable of inducing high titer invasion inhibitory antibodies supporting further development of this vaccine candidate.
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Affiliation(s)
- P V Lalitha
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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Population structure of the genes encoding the polymorphic Plasmodium falciparum apical membrane antigen 1: implications for vaccine design. Proc Natl Acad Sci U S A 2008; 105:7857-62. [PMID: 18515425 DOI: 10.1073/pnas.0802328105] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Immunization with the highly polymorphic Plasmodium falciparum apical membrane antigen 1 (PfAMA1) induces protection in animals but primarily against parasites that express the same or similar alleles. One strategy to overcome the obstacle of polymorphism is to combine PfAMA1 proteins representing major haplotypes into one vaccine. To determine the minimum number of haplotypes that would confer broad protection, we sequenced the coding region of PfAMA1 from 97 clones from around the world and 61 isolates from Mali, identifying 150 haplotypes for domains 1 to 3 that included previous sequences. A clustering algorithm grouped the 150 haplotypes into six populations that were independent of geographic location. Each of the six populations contained haplotypes predominantly of that population (predominant haplotypes) and haplotypes that were a mixture of haplotypes represented in other populations (admixed haplotypes). To determine the biological relevance of the populations identified through the clustering algorithm, antibodies induced against one predominant haplotype of population 1 (3D7) and one admixed haplotype of population 5 (FVO) were tested for their ability to block parasite invasion of erythrocytes. Parasites expressing PfAMA1s belonging to population 1 were efficiently inhibited by 3D7-specific antibodies, whereas parasites expressing PfAMA1s belonging to other populations were not. For FVO-specific antibodies, we observed growth inhibition against itself as well as isolates belonging to populations 3 and 6. Our data suggests that the inclusion of PfAMA1 sequences from each of the six populations may result in a vaccine that induces protective immunity against a broad range of malaria parasites.
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A diversity-covering approach to immunization with Plasmodium falciparum apical membrane antigen 1 induces broader allelic recognition and growth inhibition responses in rabbits. Infect Immun 2008; 76:2660-70. [PMID: 18378635 DOI: 10.1128/iai.00170-08] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum apical membrane antigen 1 (PfAMA1), a candidate malaria vaccine, is polymorphic. This polymorphism is believed to be generated predominantly under immune selection pressure and, as a result, may compromise attempts at vaccination. Alignment of 355 PfAMA1 sequences shows that around 10% of the 622 amino acid residues can vary between alleles and that linkages between polymorphic residues occur. Using this analysis, we have designed three diversity-covering (DiCo) PfAMA1 sequences that take account of these linkages and, when taken together, on average incorporate 97% of amino acid variability observed. For each of the three DiCo sequences, a synthetic gene was constructed and used to transform the methylotrophic yeast Pichia pastoris, allowing recombinant expression. All three DiCo proteins were reactive with the reduction-sensitive monoclonal antibody 4G2, suggesting the DiCo sequences had conformations similar to those of naturally occurring PfAMA1. Rabbits were immunized with FVO strain PfAMA1 or with the DiCo proteins either individually or as a mixture. Antibody titers and the ability to inhibit parasite growth in vitro were determined. Animals immunized with the DiCo mix performed similarly to animals immunized with FVO AMA1 when measured against FCR3 strain parasites but outperformed animals immunized with FVO AMA1 when assessed against other strains. The levels of growth inhibition (approximately 70%) induced by the mix of three DiCo proteins were comparable for FVO, 3D7, and HB3, suggesting that a considerable degree of diversity in AMA1 is adequately covered. This suggests that vaccines based upon the DiCo mix approach provide a broader functional immunity than immunization with a single allele.
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Pinzon-Charry A, Good MF. Malaria vaccines: the case for a whole-organism approach. Expert Opin Biol Ther 2008; 8:441-8. [DOI: 10.1517/14712598.8.4.441] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Contribution of influenza immunity and virosomal-formulated synthetic peptide to cellular immune responses in a phase I subunit malaria vaccine trial. Clin Immunol 2008; 127:188-97. [PMID: 18337175 DOI: 10.1016/j.clim.2008.01.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 01/15/2008] [Accepted: 01/15/2008] [Indexed: 12/14/2022]
Abstract
We have demonstrated recently in a phase Ia clinical trial that synthetic malaria peptides delivered by immuno-potentiating reconstituted influenza virosomes (IRIV) induced long-lived peptide-specific antibody responses in all volunteers. In the current ancillary study to this clinical trial we have investigated the cellular immune responses specific for IRIV and the surface bound synthetic malaria peptides tested. After vaccination, in 50% (8/16) of the volunteers at least one positive lymphoproliferative response specific for the 49mer peptide derived from the Plasmodium falciparum apical membrane antigen-1 (AMA-1) was observed with stimulation indices ranging from 2 to 4.5. All volunteers showed pre-existing IRIV specific cellular immunity assessed by ex vivo IFN-gamma ELISpot analysis and lymphoproliferation. The pre-existing influenza specific T cell responses did not interfere negatively with the induction of malaria peptide-specific humoral and cellular immune responses. Our results support the view that IRIV constitute a safe antigen delivery system for induction of peptide-specific immune responses in human populations.
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Petritus PM, Burns JM. Suppression of lethal Plasmodium yoelii malaria following protective immunization requires antibody-, IL-4-, and IFN-gamma-dependent responses induced by vaccination and/or challenge infection. THE JOURNAL OF IMMUNOLOGY 2008; 180:444-53. [PMID: 18097046 DOI: 10.4049/jimmunol.180.1.444] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunization with Plasmodium yoelii merozoite surface protein (PyMSP)-8 protects mice from lethal malaria but does not prevent infection. Using this merozoite surface protein-based vaccine model, we investigated vaccine- and infection-induced immune responses that contribute to protection. Analysis of prechallenge sera from rPyMSP-8-immunized C57BL/6 and BALB/c mice revealed high and comparable levels of Ag-specific IgG, but differences in isotype profile and specificity for conformational epitopes were noted. As both strains of mice were similarly protected against P. yoelii, we could not correlate vaccine-induced responses with protection. However, passive immunization studies suggested that protection resulted from differing immune responses. Studies with cytokine-deficient mice showed that protection was induced by immunization of C57BL/6 mice only when IL-4 and IFN-gamma were both present. In BALB/c mice, the absence of either IL-4 or IFN-gamma led to predictable shifts in the IgG isotype profile but did not reduce the magnitude of the Ab response induced by rPyMSP-8 immunization. Immunized IL-4-/- BALB/c mice were solidly protected against P. yoelii. To our surprise, immunized IFN-gamma-/- BALB/c mice initially controlled parasite growth but eventually succumbed to infection. Analysis of cytokine production revealed that P. yoelii infection induced two distinct peaks of IFN-gamma that correlated with periods of controlled parasite growth in intact, rPyMSP-8-immunized BALB/c mice. Maximal parasite growth occurred during a period of sustained TGF-beta production. Combined, the data indicate that induction of protective responses by merozoite surface protein-based vaccines depends on IL-4 and IFN-gamma-dependent pathways and that vaccine efficacy is significantly influenced by host responses elicited upon infection.
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Affiliation(s)
- Patricia M Petritus
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
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Dicko A, Sagara I, Ellis RD, Miura K, Guindo O, Kamate B, Sogoba M, Niambelé MB, Sissoko M, Baby M, Dolo A, Mullen GED, Fay MP, Pierce M, Diallo DA, Saul A, Miller LH, Doumbo OK. Phase 1 study of a combination AMA1 blood stage malaria vaccine in Malian children. PLoS One 2008; 3:e1563. [PMID: 18270560 PMCID: PMC2216433 DOI: 10.1371/journal.pone.0001563] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2007] [Accepted: 12/27/2007] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Apical Membrane Antigen-1 (AMA1) is one of the leading blood stage malaria vaccine candidates. AMA1-C1/Alhydrogel consists of an equal mixture of recombinant AMA1 from FVO and 3D7 clones of P. falciparum, adsorbed onto Alhydrogel. A Phase 1 study in semi-immune adults in Mali showed that the vaccine was safe and immunogenic, with higher antibody responses in those who received the 80 microg dose. The aim of this study was to assess the safety and immunogenicity of this vaccine in young children in a malaria endemic area. DESIGN This was a Phase 1 dose escalating study in 36 healthy children aged 2-3 years started in March 2006 in Donéguébougou, Mali. Eighteen children in the first cohort were randomized 2 ratio 1 to receive either 20 microg AMA1-C1/Alhydrogel or Haemophilus influenzae type b Hiberix vaccine. Two weeks later 18 children in the second cohort were randomized 2 ratio 1 to receive either 80 microg AMA1-C1/Alhydrogel or Haemophilus influenzae type b Hiberix vaccine. Vaccinations were administered on Days 0 and 28 and participants were examined on Days 1, 2, 3, 7, and 14 after vaccination and then about every two months. Results to Day 154 are reported in this manuscript. RESULTS Of 36 volunteers enrolled, 33 received both vaccinations. There were 9 adverse events related to the vaccination in subjects who received AMA1-C1 vaccine and 7 in those who received Hiberix. All were mild to moderate. No vaccine-related serious or grade 3 adverse events were observed. There was no increase in adverse events with increasing dose of vaccine or number of immunizations. In subjects who received the test vaccine, antibodies to AMA1 increased on Day 14 and peaked at Day 42, with changes from baseline significantly different from subjects who received control vaccine. CONCLUSION AMA-C1 vaccine is well tolerated and immunogenic in children in this endemic area although the antibody response was short lived. TRIAL REGISTRATION Clinicaltrials.gov NCT00341250.
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Affiliation(s)
- Alassane Dicko
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Issaka Sagara
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Ruth D. Ellis
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kazutoyo Miura
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ousmane Guindo
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Beh Kamate
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Moussa Sogoba
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Mohamed Balla Niambelé
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Mady Sissoko
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Mounirou Baby
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Amagana Dolo
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Gregory E. D. Mullen
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michael P. Fay
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mark Pierce
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dapa A. Diallo
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
| | - Allan Saul
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Louis H. Miller
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- *E-mail: (LHM); (OKD)
| | - Ogobara K. Doumbo
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali
- *E-mail: (LHM); (OKD)
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Remarque EJ, Faber BW, Kocken CHM, Thomas AW. Apical membrane antigen 1: a malaria vaccine candidate in review. Trends Parasitol 2008; 24:74-84. [PMID: 18226584 DOI: 10.1016/j.pt.2007.12.002] [Citation(s) in RCA: 217] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 10/31/2007] [Accepted: 12/20/2007] [Indexed: 10/22/2022]
Abstract
Apical membrane antigen 1 (AMA1) is a micronemal protein of apicomplexan parasites that appears to be essential during the invasion of host cells. Immune responses to Plasmodium AMA1 can have profound parasite-inhibitory effects, both as measured in vitro and in animal challenge models, suggesting AMA1 as a potential vaccine component. However, AMA1 is polymorphic, probably as a result of immune selection operating on an important target of naturally occurring immunity. The current understanding of AMA1 will be presented, particularly in relation to the vaccine potential of AMA1 and the approaches being taken towards clinical development.
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Affiliation(s)
- Edmond J Remarque
- Department of Parasitology, Biomedical Primate Research Centre, 2280 GH Rijswijk, The Netherlands
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