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Kumar V, Rumaisha, Behl A, Munjal A, Abid M, Singh S. Prefoldin subunit 6 of Plasmodium falciparum binds merozoite surface protein-1 (MSP-1). FEBS Open Bio 2020; 12:1050-1060. [PMID: 33145997 PMCID: PMC9063436 DOI: 10.1002/2211-5463.13022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/21/2020] [Accepted: 11/02/2020] [Indexed: 11/23/2022] Open
Abstract
Malaria is a human disease caused by eukaryotic protozoan parasites of the Plasmodium genus. Plasmodium falciparum (Pf) causes the most lethal form of human malaria and is responsible for widespread mortality worldwide. Prefoldin is a heterohexameric molecular complex that binds and delivers unfolded proteins to chaperonin for correct folding. The prefoldin PFD6 is predicted to interact with merozoite surface protein‐1 (MSP‐1), a protein well known to play a pivotal role in erythrocyte binding and invasion by Plasmodium merozoites. We previously found that the P. falciparum (Pf) genome contains six prefoldin genes and a prefoldin‐like gene whose molecular functions are unidentified. Here, we analyzed the expression of PfPFD‐6 during the asexual blood stages of the parasite and investigated its interacting partners. PfPFD‐6 was found to be significantly expressed at the trophozoite and schizont stages. Pull‐down assays suggest PfPFD‐6 interacts with MSP‐1. In silico analysis suggested critical residues involved in the PfPFD‐6‐MSP‐1 interaction. Our data suggest PfPFD‐6 may play a role in stabilizing or trafficking MSP‐1.
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Affiliation(s)
- Vikash Kumar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Rumaisha
- Medicinal Chemistry laboratory, Department of Biosciences, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India
| | - Ankita Behl
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Akshay Munjal
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Mohammad Abid
- Medicinal Chemistry laboratory, Department of Biosciences, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
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Loiseau C, Cooper MM, Doolan DL. Deciphering host immunity to malaria using systems immunology. Immunol Rev 2019; 293:115-143. [PMID: 31608461 DOI: 10.1111/imr.12814] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 12/11/2022]
Abstract
A century of conceptual and technological advances in infectious disease research has changed the face of medicine. However, there remains a lack of effective interventions and a poor understanding of host immunity to the most significant and complex pathogens, including malaria. The development of successful interventions against such intractable diseases requires a comprehensive understanding of host-pathogen immune responses. A major advance of the past decade has been a paradigm switch in thinking from the contemporary reductionist (gene-by-gene or protein-by-protein) view to a more holistic (whole organism) view. Also, a recognition that host-pathogen immunity is composed of complex, dynamic interactions of cellular and molecular components and networks that cannot be represented by any individual component in isolation. Systems immunology integrates the field of immunology with omics technologies and computational sciences to comprehensively interrogate the immune response at a systems level. Herein, we describe the system immunology toolkit and report recent studies deploying systems-level approaches in the context of natural exposure to malaria or controlled human malaria infection. We contribute our perspective on the potential of systems immunity for the rational design and development of effective interventions to improve global public health.
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Affiliation(s)
- Claire Loiseau
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld, Australia
| | - Martha M Cooper
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld, Australia
| | - Denise L Doolan
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld, Australia
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Lê HG, Kang JM, Jun H, Lee J, Thái TL, Myint MK, Aye KS, Sohn WM, Shin HJ, Kim TS, Na BK. Changing pattern of the genetic diversities of Plasmodium falciparum merozoite surface protein-1 and merozoite surface protein-2 in Myanmar isolates. Malar J 2019; 18:241. [PMID: 31311565 PMCID: PMC6636015 DOI: 10.1186/s12936-019-2879-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Plasmodium falciparum merozoite surface protein-1 (PfMSP-1) and -2 (PfMSP-2) are major blood-stage vaccine candidate antigens. Understanding the genetic diversity of the genes, pfmsp-1 and pfmsp-2, is important for recognizing the genetic structure of P. falciparum, and the development of an effective vaccine based on the antigens. In this study, the genetic diversities of pfmsp-1 and pfmsp-2 in the Myanmar P. falciparum were analysed. METHODS The pfmsp-1 block 2 and pfmsp-2 block 3 regions were amplified by polymerase chain reaction from blood samples collected from Myanmar patients who were infected with P. falciparum in 2013-2015. The amplified gene fragments were cloned into a T&A vector, and sequenced. Sequence analysis of Myanmar pfmsp-1 block 2 and pfmsp-2 block 3 was performed to identify the genetic diversity of the regions. The temporal genetic changes of both pfmsp-1 and pfmsp-2 in the Myanmar P. falciparum population, as well as the polymorphic diversity in the publicly available global pfmsp-1 and pfmsp-2, were also comparatively analysed. RESULTS High levels of genetic diversity of pfmsp-1 and pfmsp-2 were observed in the Myanmar P. falciparum isolates. Twenty-eight different alleles of pfmsp-1 (8 for K1 type, 14 for MAD20 type, and 6 for RO33 type) and 59 distinct alleles of pfmsp-2 (18 for FC27, and 41 for 3D7 type) were identified in the Myanmar P. falciparum population in amino acid level. Comparative analyses of the genetic diversity of the Myanmar pfmsp-1 and pfmsp-2 alleles in the recent (2013-2015) and past (2004-2006) Myanmar P. falciparum populations indicated the dynamic genetic expansion of the pfmsp-1 and pfmsp-2 in recent years, suggesting that a high level of genetic differentiation and recombination of the two genes may be maintained. Population genetic structure analysis of the global pfmsp-1 and pfmsp-2 also suggested that a high level of genetic diversity of the two genes was found in the global P. falciparum population. CONCLUSION Despite the recent remarkable decline of malaria cases, the Myanmar P. falciparum population still remains of sufficient size to allow the generation and maintenance of genetic diversity. The high level of genetic diversity of pfmsp-1 and pfmsp-2 in the global P. falciparum population emphasizes the necessity for continuous monitoring of the genetic diversity of the genes for better understanding of the genetic make-up and evolutionary aspect of the genes in the global P. falciparum population.
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Affiliation(s)
- Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Hojong Jun
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Jinyoung Lee
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Thị Lam Thái
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Moe Kyaw Myint
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Khin Saw Aye
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea. .,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
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Stabilization of a chimeric malaria antigen in separation and purification through efficient inhibition of protease activity by imidazole. Process Biochem 2018. [DOI: 10.1016/j.procbio.2017.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Man S, Fu Y, Guan Y, Feng M, Qiao K, Li X, Gao H, Cheng X. Evaluation of a Major Surface Antigen of Babesia microti Merozoites as a Vaccine Candidate against Babesia Infection. Front Microbiol 2017; 8:2545. [PMID: 29312230 PMCID: PMC5742146 DOI: 10.3389/fmicb.2017.02545] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 12/07/2017] [Indexed: 02/02/2023] Open
Abstract
Babesia species are tick-borne intraerythrocytic protozoa that cause babesiosis in humans worldwide. No vaccine has yet proven effective against Babesia infection. Surface antigens of merozoites are involved in the invasion of erythrocytes by Babesia. Surface antigens may be presented by both babesial sporozoites and merozoites and provide a general target for antibody-mediated inhibition of erythrocyte invasion. Here we evaluated a major surface antigen of B. microti merozoites, BMSA, as a potential vaccine to prevent babesiosis. Our data indicated that bmsa is transcribed during different phases, including ring form, amoeboid form, and merozoites, and that its expression is significantly increased in mature merozoites. The protein was found to be located in the membrane of B. microti and in the cytoplasm of infected erythrocytes. The immune response induced by BMSA had a significant inhibitory effect on parasite invasion of the host erythrocytes (83.3% inhibition of invasion) and parasite growth in vivo. The levels of parasitemia significantly decreased after BMSA vaccination when mice were infected with babesia parasite. Importantly, protective immunity was significantly related to the upregulation of the Th17 cytokine interleukin-17, the Th1 cytokine interleukin-12p70 and the Th2 cytokines, such as interleukin-4, -6, and -10. Ingenuity Pathway Analysis indicated that interleukin-17 facilitated the secretion of Th2 cytokines, such as interleukin-10, -4, and -6, thereby inducing a predominately Th2 protective immune response and promoting the expression a high level of special IgG1 against Babesia infection. Further, an anti-BMSA monoclonal antibody successfully protected NOD/SCID mice from a challenge with B. microti. Taken together, our results indicated that BMSA induces a protective immune response against Babesia infection and may serve as a potential vaccine.
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Affiliation(s)
- Suqin Man
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yongfeng Fu
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yue Guan
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Meng Feng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Ke Qiao
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xueping Li
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Hongjian Gao
- Department of Electron Microscopy, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Xunjia Cheng
- Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai, China.,Institute of Biomedical Sciences, Fudan University, Shanghai, China
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A review of reverse vaccinology approaches for the development of vaccines against ticks and tick borne diseases. Ticks Tick Borne Dis 2015; 7:573-85. [PMID: 26723274 DOI: 10.1016/j.ttbdis.2015.12.012] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/24/2015] [Accepted: 12/12/2015] [Indexed: 02/07/2023]
Abstract
The field of reverse vaccinology developed as an outcome of the genome sequence revolution. Following the introduction of live vaccinations in the western world by Edward Jenner in 1798 and the coining of the phrase 'vaccine', in 1881 Pasteur developed a rational design for vaccines. Pasteur proposed that in order to make a vaccine that one should 'isolate, inactivate and inject the microorganism' and these basic rules of vaccinology were largely followed for the next 100 years leading to the elimination of several highly infectious diseases. However, new technologies were needed to conquer many pathogens which could not be eliminated using these traditional technologies. Thus increasingly, computers were used to mine genome sequences to rationally design recombinant vaccines. Several vaccines for bacterial and viral diseases (i.e. meningococcus and HIV) have been developed, however the on-going challenge for parasite vaccines has been due to their comparatively larger genomes. Understanding the immune response is important in reverse vaccinology studies as this knowledge will influence how the genome mining is to be conducted. Vaccine candidates for anaplasmosis, cowdriosis, theileriosis, leishmaniasis, malaria, schistosomiasis, and the cattle tick have been identified using reverse vaccinology approaches. Some challenges for parasite vaccine development include the ability to address antigenic variability as well the understanding of the complex interplay between antibody, mucosal and/or T cell immune responses. To understand the complex parasite interactions with the livestock host, there is the limitation where algorithms for epitope mining using the human genome cannot directly be adapted for bovine, for example the prediction of peptide binding to major histocompatibility complex motifs. As the number of genomes for both hosts and parasites increase, the development of new algorithms for pan-genomic mining will continue to impact the future of parasite and ricketsial (and other tick borne pathogens) disease vaccine development.
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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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Ahmedou Salem MSO, Ndiaye M, OuldAbdallahi M, Lekweiry KM, Bogreau H, Konaté L, Faye B, Gaye O, Faye O, Mohamed Salem O Boukhary AO. Polymorphism of the merozoite surface protein-1 block 2 region in Plasmodium falciparum isolates from Mauritania. Malar J 2014; 13:26. [PMID: 24456636 PMCID: PMC3902025 DOI: 10.1186/1475-2875-13-26] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 01/21/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The genetic diversity of Plasmodium falciparum has been extensively studied in various parts of the world. However, limited data are available from Mauritania. The present study examined and compared the genetic diversity of P. falciparum isolates in Mauritania. METHODS Plasmodium falciparum isolates blood samples were collected from 113 patients attending health facilities in Nouakchott and Hodh El Gharbi regions. K1, Mad20 and RO33 allelic family of msp-1 gene were determined by nested PCR amplification. RESULTS K1 family was the predominant allelic type carried alone or in association with Ro33 and Mad20 types (90%; 102/113). Out of the 113 P. falciparum samples, 93(82.3%) harboured more than one parasite genotype. The overall multiplicity of infection was 3.2 genotypes per infection. There was no significant correlation between multiplicity of infection and age of patients. A significant increase of multiplicity of infection was correlated with parasite densities. CONCLUSIONS The polymorphism of P. falciparum populations from Mauritania was high. Infection with multiple P. falciparum clones was observed, as well as a high multiplicity of infection reflecting both the high endemicity level and malaria transmission in Mauritania.
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Affiliation(s)
- Mohamed Salem O Ahmedou Salem
- Laboratoire de Biotechnologie, Faculté des Sciences et Techniques, Université des Sciences, de Technologie et de Médecine, Nouakchott, PO Box 5026, Nouakchott, Mauritanie
- Laboratoire d’Ecologie Vectorielle et Parasitaire, Faculté des sciences et techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Magatte Ndiaye
- Service de Parasitologie-Mycologie, Faculté de Médecine, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Mohamed OuldAbdallahi
- Service de Parasitologie et de Mycologie, Institut National de Recherches en Santé Publique, BP 695, Nouakchott, Mauritanie
| | - Khadijetou M Lekweiry
- Laboratoire de Biotechnologie, Faculté des Sciences et Techniques, Université des Sciences, de Technologie et de Médecine, Nouakchott, PO Box 5026, Nouakchott, Mauritanie
| | - Hervé Bogreau
- Unité de Parasitologie, Département d’Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, BP 7391 223 Brétigny-sur-Orge cedex, France
- Aix Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS 7278, IRD 198, INSERM 1095, Faculté de Médecine La Timone, 27 boulevard Jean Moulin, 13385 Marseille cedex 5 Marseille, France
- Unité de Parasitologie Institut Pasteur, 23 Avenue Pasteur, BP 6010, 97306 Cayenne cedex Guyane, France
| | - Lassana Konaté
- Laboratoire d’Ecologie Vectorielle et Parasitaire, Faculté des sciences et techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Babacar Faye
- Service de Parasitologie-Mycologie, Faculté de Médecine, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Oumar Gaye
- Service de Parasitologie-Mycologie, Faculté de Médecine, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Ousmane Faye
- Laboratoire d’Ecologie Vectorielle et Parasitaire, Faculté des sciences et techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Ali O Mohamed Salem O Boukhary
- Laboratoire de Biotechnologie, Faculté des Sciences et Techniques, Université des Sciences, de Technologie et de Médecine, Nouakchott, PO Box 5026, Nouakchott, Mauritanie
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Planson AG, Guijarro JI, Chaffotte AF. New insights for native production of MSP1(19), the disulfide-rich C-terminal fragment from Plasmodium falciparum merozoite surface protein 1. PLoS One 2013; 8:e57086. [PMID: 23451153 PMCID: PMC3579805 DOI: 10.1371/journal.pone.0057086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/17/2013] [Indexed: 11/18/2022] Open
Abstract
Malaria represents a major public health problem and an important cause of mortality and morbidity. The malaria parasites are becoming resistant to drugs used to treat the disease and still no efficient vaccine has been developed. One promising vaccine candidate is the merozoite surface protein 1 (MSP1), which has been extensively investigated as a vaccine target. The surface protein MSP1 plays an essential role in the erythrocyte invasion process and is an accessible target for the immune system. Antibodies to the carboxy-terminal region of the protein, named MSP119, can inhibit erythrocyte invasion and parasite growth. In order to develop an effective MSP119- based vaccine against malaria, production of an antigen that is recognized by protective antibodies is mandatory. To this aim, we propose a method to produce the disulfide-rich MSP119 in its native conformation based on its in vitro oxidative refolding. The native conformation of the renatured MSP119 is carefully established by immunochemical reactivity experiments, circular dichroism and NMR. MSP119 can successfully be refolded in vitro as an isolated protein or as a fusion with the maltose binding protein. The possibility to properly fold MSP119in vitro paves the way to new approaches for high titer production of native MSP119 using Escherichia coli as a host.
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Affiliation(s)
| | - J. Iñaki Guijarro
- Unité de RMN des Biomolécules, Institut Pasteur, Paris, France
- CNRS UMR 3528, Paris, France
- * E-mail: (JIG); (AFC)
| | - Alain F. Chaffotte
- Unité de RMN des Biomolécules, Institut Pasteur, Paris, France
- CNRS UMR 3528, Paris, France
- * E-mail: (JIG); (AFC)
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Bergmann-Leitner ES, Duncan EH, Mease RM, Angov E. Impact of pre-existing MSP1(42)-allele specific immunity on potency of an erythrocytic Plasmodium falciparum vaccine. Malar J 2012; 11:315. [PMID: 22958482 PMCID: PMC3502560 DOI: 10.1186/1475-2875-11-315] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/30/2012] [Indexed: 01/03/2023] Open
Abstract
Background MSP1 is the major surface protein on merozoites and a prime candidate for a blood stage malaria vaccine. Preclinical and seroepidemiological studies have implicated antibodies to MSP1 in protection against blood stage parasitaemia and/or reduced parasite densities, respectively. Malaria endemic areas have multiple strains of Plasmodium falciparum circulating at any given time, giving rise to complex immune responses, an issue which is generally not addressed in clinical trials conducted in non-endemic areas. A lack of understanding of the effect of pre-existing immunity to heterologous parasite strains may significantly contribute to vaccine failure in the field. The purpose of this study was to model the effect of pre-existing immunity to MSP142 on the immunogenicity of blood-stage malaria vaccines based on alternative MSP1 alleles. Methods Inbred and outbred mice were immunized with various recombinant P. falciparum MSP142 proteins that represent the two major alleles of MSP142, MAD20 (3D7) and Wellcome (K1, FVO). Humoral immune responses were analysed by ELISA and LuminexTM, and functional activity of induced MSP142-specific antibodies was assessed by growth inhibition assays. T-cell responses were characterized using ex vivo ELISpot assays. Results Analysis of the immune responses induced by various immunization regimens demonstrated a strong allele-specific response at the T cell level in both inbred and outbred mice. The success of heterologous regimens depended on the degree of homology of the N-terminal p33 portion of the MSP142, likely due to the fact that most T cell epitopes reside in this part of the molecule. Analysis of humoral immune responses revealed a marked cross-reactivity between the alleles. Functional analyses showed that some of the heterologous regimens induced antibodies with improved growth inhibitory activities. Conclusion The development of a more broadly efficacious MSP1 based vaccine may be hindered by clonally imprinted p33 responses mainly restricted at the T cell level. In this study, the homology of the p33 sequence between the clonally imprinted response and the vaccine allele determines the magnitude of vaccine induced responses.
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Affiliation(s)
- Elke S Bergmann-Leitner
- Malaria Vaccine Branch, US Military Malaria Vaccine Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
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Mehrizi AA, Zakeri S, Rafati S, Salmanian AH, Djadid ND. Immune responses elicited by co-immunization of Plasmodium vivax and P. falciparum MSP-1 using prime-boost immunization strategies. Parasite Immunol 2012; 33:594-608. [PMID: 21883290 DOI: 10.1111/j.1365-3024.2011.01331.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carboxy-terminus of merozoite surface protein-1 (MSP-1(19) ) is the major protein on the surface of the plasmodial merozoite that acts as one of the most important blood-stage vaccine candidates. The present investigation was designed to evaluate the immune responses when either two recombinant antigens (rPvMSP-1(19) + rPfMSP-1(19)) or two plasmid constructs (pcDNA3.1 hygro-PvMSP-1(19) + pcDNA3.1 hygro-PfMSP-1(19)) were administered in combination at a single site in mice by using different immunization strategies (protein/protein, DNA/DNA and DNA/protein) at weeks 0, 5 and 8. All mice were monitored for the level of MSP-1(19) -specific antibody for up to 40 weeks. The inclusion of both recombinant antigens in a vaccine mixture could not inhibit induction of antibodies to the other antigen when the two recombinant antigens were combined in immunization formulation. Interestingly, antisera from immunized mice with either recombinant antigen failed to cross-react with heterologous antigen. Moreover, the results of this study showed that co-immunization with both antigens at a single site generated a substantial PvMSP-1(19) - and PfMSP-1(19) -specific antibody responses and also IFN-γ cytokine production (Th1 response) in DNA/protein prime-boost immunization strategies. The increased humoral response to PvMSP-1(19) and PfMSP-1(19) lasted nearly a year after immunization. Therefore, the results of this study are encouraging for the development of multi-species malaria vaccine based on MSP-1(19) antigen.
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Affiliation(s)
- A A Mehrizi
- Malaria and Vector Research Group, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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Plasmodium falciparum 19-kilodalton merozoite surface protein 1 (MSP1)-specific antibodies that interfere with parasite growth in vitro can inhibit MSP1 processing, merozoite invasion, and intracellular parasite development. Infect Immun 2011; 80:1280-7. [PMID: 22202121 DOI: 10.1128/iai.05887-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Merozoite surface protein 1 (MSP1) is a target for malaria vaccine development. Antibodies to the 19-kDa carboxy-terminal region referred to as MSP1(19) inhibit erythrocyte invasion and parasite growth, with some MSP1-specific antibodies shown to inhibit the proteolytic processing of MSP1 that occurs at invasion. We investigated a series of antibodies purified from rabbits immunized with MSP1(19) and AMA1 recombinant proteins for their ability to inhibit parasite growth, initially looking at MSP1 processing. Although significant inhibition of processing was mediated by several of the antibody samples, there was no clear relationship with overall growth inhibition by the same antibodies. However, no antibody samples inhibited processing but not invasion, suggesting that inhibition of MSP1 processing contributes to but is not the only mechanism of antibody-mediated inhibition of invasion and growth. Examining other mechanisms by which MSP1-specific antibodies inhibit parasite growth, we show that MSP1(19)-specific antibodies are taken up into invaded erythrocytes, where they persist for significant periods and result in delayed intracellular parasite development. This delay may result from antibody interference with coalescence of MSP1(19)-containing vesicles with the food vacuole. Antibodies raised against a modified recombinant MSP1(19) sequence were more efficient at delaying intracellular growth than those to the wild-type protein. We propose that antibodies specific for MSP1(19) can mediate inhibition of parasite growth by at least three mechanisms: inhibition of MSP1 processing, direct inhibition of invasion, and inhibition of parasite development following invasion. The balance between mechanisms may be modulated by modifying the immunogen used to induce the antibodies.
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Khaminsou N, Kritpetcharat O, Daduang J, Charerntanyarak L, Kritpetcharat P. Genetic analysis of the merozoite surface protein-1 block 2 allelic types in Plasmodium falciparum clinical isolates from Lao PDR. Malar J 2011; 10:371. [PMID: 22177111 PMCID: PMC3281801 DOI: 10.1186/1475-2875-10-371] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 12/17/2011] [Indexed: 11/14/2022] Open
Abstract
Background MSP-1 is one of the potential malarial vaccine candidate antigens. However, extensive genetic polymorphism of this antigen in the field isolates of Plasmodium falciparum represents a major hindrance for the development of an effective vaccine. Therefore, this study aimed to establish the prevalence and genetic polymorphisms of K1, MAD20 and RO33 allelic types of msp-1 block 2 among P. falciparum clinical isolates from Lao PDR. Methods Plasmodium falciparum isolates were collected from 230 P. falciparum-infected blood samples from three regions of Lao PDR. K1, MAD20 and RO33 were detected by nested PCR; SSCP was used for polymorphism screening. The nested PCR products of each K1, MAD20 and RO33 allelic types that had different banding patterns by SSCP, were sequenced. Results The overall prevalence of K1, MAD20 and RO33 allelic types in P. falciparum isolates from Lao PDR were 66.95%, 46.52% and 31.30%, respectively, of samples under study. Single infections with K1, MAD20 and RO33 allelic types were 27.83%, 11.74% and 5.22%, respectively; the remainders were multiple clonal infections. Neither parasite density nor age was related to MOI. Sequence analysis revealed that there were 11 different types of K1, eight different types of MAD20, and 7 different types of RO33. Most of them were regional specific, except type 1 of each allelic type was common found in 3 regions under study. Conclusions Genetic polymorphism with diverse allele types was identified in msp-1 block 2 among P. falciparum clinical isolates in Lao PDR. A rather high level of multiple clonal infections was also observed but the multiplicity of infection was rather low as not exceed 2.0. This basic data are useful for treatment and malaria control program in Lao PDR.
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Affiliation(s)
- Naly Khaminsou
- Faculty of Medical Technology, University of Health Science, Vientiane, Lao PDR
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14
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de Silva HD, Saleh S, Kovacevic S, Wang L, Black CG, Plebanski M, Coppel RL. The antibody response to Plasmodium falciparum Merozoite Surface Protein 4: comparative assessment of specificity and growth inhibitory antibody activity to infection-acquired and immunization-induced epitopes. Malar J 2011; 10:266. [PMID: 21920045 PMCID: PMC3182980 DOI: 10.1186/1475-2875-10-266] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 09/16/2011] [Indexed: 11/16/2022] Open
Abstract
Background Malaria remains a global public health challenge. It is widely believed that an effective vaccine against malaria will need to incorporate multiple antigens from the various stages of the parasite's complex life cycle. Plasmodium falciparum Merozoite Surface Protein 4 (MSP4) is a vaccine candidate that has been selected for development for inclusion in an asexual stage subunit vaccine against malaria. Methods Nine monoclonal antibodies (Mabs) were produced against Escherichia coli-expressed recombinant MSP4 protein and characterized. These Mabs were used to develop an MSP4-specific competition ELISA to test the binding specificity of antibodies present in sera from naturally P. falciparum-infected individuals from a malaria endemic region of Vietnam. The Mabs were also tested for their capacity to induce P. falciparum growth inhibition in vitro and compared against polyclonal rabbit serum raised against recombinant MSP4 Results All Mabs reacted with native parasite protein and collectively recognized at least six epitopes. Four of these Mabs recognize reduction-sensitive epitopes within the epidermal growth factor-like domain found near the C-terminus of MSP4. These sera were shown to contain antibodies capable of inhibiting the binding of the six Mabs indicating infection-acquired responses to the six different epitopes of MSP4. All of the six epitopes were readily recognized by human immune sera. Competition ELISA titres varied from 20 to 640, reflecting heterogeneity in the intensity of the humoral response against the protein among different individuals. The IgG responses during acute and convalescent phases of infection were higher to epitopes in the central region than to other parts of MSP4. Immunization with full length MSP4 in Freund's adjuvant induced rabbit polyclonal antisera able to inhibit parasite growth in vitro in a manner proportionate to the antibody titre. By contrast, polyclonal antisera raised to individual recombinant fragments rMSP4A, rMSP4B, rMSP4C and rMSP4D gave negligible inhibition. Similarly, murine Mabs alone or in combination did not inhibit parasite growth. Conclusions The panel of MSP4-specific Mabs produced were found to recognize six distinct epitopes that are also targeted by human antibodies during natural malaria infection. Antibodies directed to more than three epitope regions spread across MSP4 are likely to be required for P. falciparum growth inhibition in vitro.
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Affiliation(s)
- Harini D de Silva
- Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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Cavanagh DR, Dubois PM, Holtel A, Kisser A, Leroy O, Locke E, Moorthy VS, Remarque EJ, Shi YP. Towards validated assays for key immunological outcomes in malaria vaccine development. Vaccine 2011; 29:3093-5. [DOI: 10.1016/j.vaccine.2011.01.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/11/2011] [Accepted: 01/21/2011] [Indexed: 10/18/2022]
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Malaria Vaccine Development: Are Bacterial Flagellin Fusion Proteins the Bridge between Mouse and Humans? J Parasitol Res 2011; 2011:965369. [PMID: 21603205 PMCID: PMC3095412 DOI: 10.1155/2011/965369] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 01/18/2011] [Indexed: 12/25/2022] Open
Abstract
In the past 25 years, the development of an effective malaria vaccine has become one of the biggest riddles in the biomedical sciences. Experimental data using animal infection models demonstrated that it is possible to induce protective immunity against different stages of malaria parasites. Nonetheless, the vast body of knowledge has generated disappointments when submitted to clinical conditions and presently a single antigen formulation has progressed to the point where it may be translated into a human vaccine. In parallel, new means to increase the protective effects of antigens in general have been pursued and depicted, such as the use of bacterial flagellins as carriers/adjuvants. Flagellins activate pathways in the innate immune system of both mice and humans. The recent report of the first Phase I clinical trial of a vaccine containing a Salmonella flagellin as carrier/adjuvant may fuel the use of these proteins in vaccine formulations. Herein, we review the studies on the use of recombinant flagellins as vaccine adjuvants with malarial antigens in the light of the current state of the art of malaria vaccine development. The available information indicates that bacterial flagellins should be seriously considered for malaria vaccine formulations to the development of effective human vaccines.
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Douglas AD, de Cassan SC, Dicks MDJ, Gilbert SC, Hill AVS, Draper SJ. Tailoring subunit vaccine immunogenicity: maximizing antibody and T cell responses by using combinations of adenovirus, poxvirus and protein-adjuvant vaccines against Plasmodium falciparum MSP1. Vaccine 2011; 28:7167-78. [PMID: 20937436 PMCID: PMC3404461 DOI: 10.1016/j.vaccine.2010.08.068] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 12/15/2022]
Abstract
Subunit vaccination modalities tend to induce particular immune effector responses. Viral vectors are well known for their ability to induce strong T cell responses, while protein-adjuvant vaccines have been used primarily for induction of antibody responses. Here, we demonstrate in mice using a Plasmodium falciparum merozoite surface protein 1 (PfMSP1) antigen that novel regimes combining adenovirus and poxvirus vectored vaccines with protein antigen in Montanide ISA720 adjuvant can achieve simultaneous antibody and T cell responses which equal, or in some cases surpass, the best immune responses achieved by either the viral vectors or the protein vaccine alone. Such broad responses can be achieved either using three-stage vaccination protocols, or with an equally effective two-stage protocol in which viral vectors are admixed with protein and adjuvant, and were apparent despite the use of a protein antigen that represented only a portion of the viral vector antigen. We describe further possible advantages of viral vectors in achieving consistent antibody priming, enhanced antibody avidity, and cytophilic isotype skew. These data strengthen the evidence that tailored combinations of vaccine platforms can achieve desired combinations of immune responses, and further encourage the co-administration of antibody-inducing recombinant protein vaccines with T cell- and antibody-inducing recombinant viral vectors as one strategy that may achieve protective blood-stage malaria immunity in humans.
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Yoshida S, Nagumo H, Yokomine T, Araki H, Suzuki A, Matsuoka H. Plasmodium berghei circumvents immune responses induced by merozoite surface protein 1- and apical membrane antigen 1-based vaccines. PLoS One 2010; 5:e13727. [PMID: 21060850 PMCID: PMC2965677 DOI: 10.1371/journal.pone.0013727] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 09/07/2010] [Indexed: 11/30/2022] Open
Abstract
Background Two current leading malaria blood-stage vaccine candidate antigens for Plasmodium falciparum, the C-terminal region of merozoite surface protein 1 (MSP119) and apical membrane antigen 1 (AMA1), have been prioritized because of outstanding protective efficacies achieved in a rodent malaria Plasmodium yoelii model. However, P. falciparum vaccines based on these antigens have had disappointing outcomes in clinical trials. Discrepancies in the vaccine efficacies observed between the P. yoelii model and human clinical trials still remain problematic. Methodology and Results In this study, we assessed the protective efficacies of a series of MSP119- and AMA1-based vaccines using the P. berghei rodent malarial parasite and its transgenic models. Immunization of mice with a baculoviral-based vaccine (BBV) expressing P. falciparum MSP119 induced high titers of PfMSP119-specific antibodies that strongly reacted with P. falciparum blood-stage parasites. However, no protection was achieved following lethal challenge with transgenic P. berghei expressing PfMSP119 in place of native PbMSP119. Similarly, neither P. berghei MSP119- nor AMA1-BBV was effective against P. berghei. In contrast, immunization with P. yoelii MSP119- and AMA1-BBVs provided 100% and 40% protection, respectively, against P. yoelii lethal challenge. Mice that naturally acquired sterile immunity against P. berghei became cross-resistant to P. yoelii, but not vice versa. Conclusion This is the first study to address blood-stage vaccine efficacies using both P. berghei and P. yoelii models at the same time. P. berghei completely circumvents immune responses induced by MSP119- and AMA1-based vaccines, suggesting that P. berghei possesses additional molecules and/or mechanisms that circumvent the host's immune responses to MSP119 and AMA1, which are lacking in P. yoelii. Although it is not known whether P. falciparum shares these escape mechanisms with P. berghei, P. berghei and its transgenic models may have potential as useful tools for identifying and evaluating new blood-stage vaccine candidate antigens for P. falciparum.
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Affiliation(s)
- Shigeto Yoshida
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Tochigi, Japan.
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Lalitha PV, Biswas S, Pillai CR, Seth RK, Saxena RK. Expression, purification and characterization of allelic variants of MSP-1(42) from Indian Plasmodium falciparum isolates. Vaccine 2010; 28:4661-7. [PMID: 20452429 DOI: 10.1016/j.vaccine.2010.04.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Revised: 04/10/2010] [Accepted: 04/23/2010] [Indexed: 10/19/2022]
Abstract
The C-terminal 19 and 42 kDa fragments of Plasmodium falciparum merozoite surface protein 1 (MSP-1) have shown to be protective in animals against lethal parasite challenge. The MSP-1(19) being highly conserved may lack sufficient number of T-cell epitopes in order to elicit a broader response in genetically diverse populations. The inclusion of additional epitopes from the N-terminal MSP-1(42) has shown to enhance the protective efficacy of MSP-1(19) vaccine. In an attempt to examine the strain specific immunogenicity to MSP-1, we have cloned and expressed three diverse allelic variants of MSP-1(42) from Indian P. falciparum isolates in bacteria. Among three alleles, one was extremely rare and not been found before. These purified and refolded recombinant products were recognized by conformation specific monoclonal antibodies and hyper-immune sera. Immunization of mice and rabbits with the purified proteins generated high titer biologically active polyclonal antibodies supporting further development of this vaccine candidate antigen.
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Affiliation(s)
- P V Lalitha
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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Moorthy VS, Kieny MP. Reducing empiricism in malaria vaccine design. THE LANCET. INFECTIOUS DISEASES 2010; 10:204-11. [PMID: 20185099 DOI: 10.1016/s1473-3099(09)70329-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Gains in the control of malaria and the promising progress of a malaria vaccine that is partly efficacious do not reduce the need for a high-efficacy vaccine in the longer term. Evidence supports the feasibility of developing a highly efficacious malaria vaccine. However, design of candidate malaria vaccines remains empirical and is necessarily based on many unproven assumptions because much of the knowledge needed to design vaccines and to predict efficacy is not available. Data to inform key questions of vaccine science might allow the design of vaccines to progress to a less empirical stage, for example through availability of assay results associated with vaccine efficacy. We discuss six strategic gaps in knowledge that contribute to empiricism in the design of vaccines. Comparative evaluation, assay and model standardisation, greater sharing of information, collaboration and coordination between groups, and rigorous evaluation of existing datasets are steps that can be taken to enable reductions in empiricism over time.
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Immunogenic properties of a recombinant fusion protein containing the C-terminal 19 kDa of Plasmodium falciparum merozoite surface protein-1 and the innate immunity agonist FliC flagellin of Salmonella typhimurium. Vaccine 2010; 28:2818-26. [PMID: 20170765 DOI: 10.1016/j.vaccine.2010.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 01/30/2010] [Accepted: 02/03/2010] [Indexed: 12/17/2022]
Abstract
In a recent study, we demonstrated the immunogenic properties of a new malaria vaccine polypeptide based on a 19 kDa C-terminal fragment of the merozoite surface protein-1 (MSP1(19)) from Plasmodium vivax and an innate immunity agonist, the Salmonella enterica serovar Typhimurium flagellin (FliC). Herein, we tested whether the same strategy, based on the MSP1(19) component of the deadly malaria parasite Plasmodium falciparum, could also generate a fusion polypeptide with enhanced immunogenicity. The His(6)FliC-MSP1(19) fusion protein was expressed from a recombinant Escherichia coli and showed preserved in vitro TLR5-binding activity. In contrast to animals injected with His(6)MSP1(19), mice subcutaneously immunised with the recombinant His(6)FliC-MSP1(19) developed strong MSP1(19)-specific systemic antibody responses with a prevailing IgG1 subclass. Incorporation of other adjuvants, such as CpG ODN 1826, complete and incomplete Freund's adjuvants or Quil-A, improved the IgG responses after the second, but not the third, immunising dose. It also resulted in a more balanced IgG subclass response, as evaluated by the IgG1/IgG2c ratio, and higher cell-mediated immune response, as determined by the detection of antigen-specific interferon-gamma secretion by immune spleen cells. MSP1(19)-specific antibodies recognised not only the recombinant protein, but also the native protein expressed on the surface of P. falciparum parasites. Finally, sera from rabbits immunised with the fusion protein alone inhibited the in vitro growth of three different P. falciparum strains. In summary, these results extend our previous observations and further demonstrate that fusion of the innate immunity agonist FliC to Plasmodium antigens is a promising alternative to improve their immunogenicity.
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Singh B, Cabrera-Mora M, Jiang J, Galinski M, Moreno A. Genetic linkage of autologous T cell epitopes in a chimeric recombinant construct improves anti-parasite and anti-disease protective effect of a malaria vaccine candidate. Vaccine 2010; 28:2580-92. [PMID: 20097151 DOI: 10.1016/j.vaccine.2010.01.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 12/28/2009] [Accepted: 01/13/2010] [Indexed: 10/19/2022]
Abstract
We have reported the design of polyvalent synthetic and recombinant chimeras that include promiscuous T cell epitopes as a viable delivery system for pre-erythrocytic subunit malaria vaccines. To further assess the ability of several Plasmodium T cell epitopes to enhance vaccine potency, we designed a synthetic gene encoding four Plasmodium yoelii merozoite surface protein 1 (PyMSP1) CD4(+) promiscuous T cell epitopes fused in tandem to the homologous carboxyl terminal PyMSP1(19) fragment. This Recombinant Modular Chimera (PyRMC-MSP1(19)) was tested for immunogenicity and protective efficacy in comparative experiments with a recombinant protein expressing only the PyMSP1(19) fragment. Both proteins induced comparable antibody responses. However PyRMC-MSP1(19) elicited higher anti-parasite antibody titers and more robust protection against both hyper-parasitemia and malarial anemia. Most importantly, passive transfer of anti-PyRMC-MSP1(19), but not anti-PyMSP1(19) antibodies protected against heterologous challenge. These studies show that protective efficacy can be significantly improved by inclusion of an array of autologous promiscuous T cell epitopes in vaccine constructs.
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Affiliation(s)
- Balwan Singh
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
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Craig AG, Holder AA, Leroy OY, Ventura RA. Malaria vaccines – how and when to proceed? Trends Parasitol 2009; 25:535-7. [DOI: 10.1016/j.pt.2009.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 09/17/2009] [Accepted: 09/18/2009] [Indexed: 11/26/2022]
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In vitro growth-inhibitory activity and malaria risk in a cohort study in mali. Infect Immun 2009; 78:737-45. [PMID: 19917712 DOI: 10.1128/iai.00960-09] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immunity to the asexual blood stage of Plasmodium falciparum is complex and likely involves several effector mechanisms. Antibodies are thought to play a critical role in malaria immunity, and a corresponding in vitro correlate of antibody-mediated immunity has long been sought to facilitate malaria vaccine development. The growth inhibition assay (GIA) measures the capacity of antibodies to limit red blood cell (RBC) invasion and/or growth of P. falciparum in vitro. In humans, naturally acquired and vaccine-induced P. falciparum-specific antibodies have growth-inhibitory activity, but it is unclear if growth-inhibitory activity correlates with protection from clinical disease. In a longitudinal study in Mali, purified IgGs, obtained from plasmas collected before the malaria season from 220 individuals aged 2 to 10 and 18 to 25 years, were assayed for growth-inhibitory activity. Malaria episodes were recorded by passive surveillance over the subsequent 6-month malaria season. Logistic regression showed that greater age (odds ratio [OR], 0.78; 95% confidence interval [95% CI], 0.63 to 0.95; P = 0.02) and growth-inhibitory activity (OR, 0.50; 95% CI, 0.30 to 0.85; P = 0.01) were significantly associated with decreased malaria risk in children. A growth-inhibitory activity level of 40% was determined to be the optimal cutoff for discriminating malaria-immune and susceptible individuals in this cohort, with a sensitivity of 97.0%, but a low specificity of 24.3%, which limited the assay's ability to accurately predict protective immunity and to serve as an in vitro correlate of antibody-mediated immunity. These data suggest that antibodies which block merozoite invasion of RBC and/or inhibit the intra-RBC growth of the parasite contribute to but are not sufficient for the acquisition of malaria immunity.
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Growth-inhibitory antibodies are not necessary for protective immunity to malaria infection. Infect Immun 2009; 78:680-7. [PMID: 19917716 DOI: 10.1128/iai.00939-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The absence of a validated surrogate marker for the immune state has complicated the design of a subunit vaccine against asexual stages of Plasmodium falciparum. In particular, it is not known whether the capacity to induce antibodies that inhibit parasite growth in vitro is an important criterion for selection of P. falciparum proteins to be assessed in human vaccine trials. We examined this issue in the Plasmodium yoelii rodent malaria model using the 19-kDa C-terminal fragment of merozoite surface protein 1 (MSP1(19)). To examine the relationship between inhibitory antibodies in immunized mice and the immune state, as indicated by resistance to a blood-stage challenge, we used an allelic replacement strategy to generate a transgenic P. falciparum line that expresses MSP1(19) from P. yoelii. We show that MSP1(19) is functionally conserved across these two divergent Plasmodium species, and replacing PfMSP1(19) with PyMSP1(19) has no detectable effect on parasite growth in vitro. By comparing growth rates of this transgenic line with a matched transgenic line that expresses the endogenous PfMSP1(19), we developed an assay to measure the specific growth-inhibitory activity directed exclusively to the PyMSP1(19) protein in the sera from vaccinated animals. To validate this assay, sera from rabbits immunized with recombinant PyMSP1(19) were tested and showed specific inhibitory activity in a concentration-dependent manner. In mice that were immunized with recombinant PyMSP1(19), the levels of PyMSP1(19)-specific inhibitory activity did not correlate with the total antibody levels measured by enzyme-linked immunosorbent assay. Furthermore, they did not correlate with resistance to subsequent blood-stage infection, and some mice with complete protection showed no detectable inhibitory activity in their prechallenge sera. These data indicated that growth-inhibitory activity measured in vitro was not a reliable predictor of immune status in vivo, and the reliance on this criterion to select vaccine candidates for human clinical trials may be misplaced. The transgenic lines further offer useful tools for comparing the efficacy of MSP1(19)-based vaccines that utilize different immunization regimens and antigen formulations.
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Bergmann-Leitner ES, Duncan EH, Angov E. MSP-1p42-specific antibodies affect growth and development of intra-erythrocytic parasites of Plasmodium falciparum. Malar J 2009; 8:183. [PMID: 19650894 PMCID: PMC2729774 DOI: 10.1186/1475-2875-8-183] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 08/03/2009] [Indexed: 11/10/2022] Open
Abstract
Background Antibodies are the main effector molecules in the defense against blood stages of the malaria parasite Plasmodium falciparum. Understanding the mechanisms by which vaccine-induced anti-blood stage antibodies work in protecting against malaria is essential for vaccine design and testing. Methods The effects of MSP-1p42-specific antibodies on the development of blood stage parasites were studied using microscopy, flow cytometry and the pLDH assay. To determine allele-specific effects, if present, allele-specific antibodies and the various parasite clones representative of these alleles of MSP-1 were employed. Results The mode of action of anti-MSP-1p42 antibodies differs among the parasite clones tested: anti-MSP-1p42 sera act mainly through invasion-inhibitory mechanisms against FVO parasites, by either preventing schizonts from rupturing or agglutinating merozoites upon their release. The same antibodies do not prevent the rupture of 3D7 schizonts; instead they agglutinate merozoites and arrest the development of young parasites at the early trophozoite stage, thus acting through both invasion- and growth inhibitory mechanisms. The second key finding is that antibodies have access to the intra-erythrocytic parasite, as evidenced by the labeling of developing merozoites with fluorochrome-conjugated anti-MSP-1p42 antibodies. Access to the parasite through this route likely allows antibodies to exert their inhibitory activities on the maturing schizonts leading to their inability to rupture and be released as infectious merozoites. Conclusion The identification of various modes of action by which anti-MSP-1 antibodies function against the parasite during erythrocytic development emphasizes the importance of functional assays for evaluating malaria vaccines and may also open new avenues for immunotherapy and vaccine development.
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Affiliation(s)
- Elke S Bergmann-Leitner
- US Military Malaria Vaccine Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
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Inhibitory antibodies specific for the 19-kilodalton fragment of merozoite surface protein 1 do not correlate with delayed appearance of infection with Plasmodium falciparum in semi-immune individuals in Vietnam. Infect Immun 2009; 77:4510-7. [PMID: 19620342 DOI: 10.1128/iai.00360-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inhibitory antibodies specific for the 19-kDa fragment of merozoite surface protein 1 (MSP1(19)) are a significant component of inhibitory responses in individuals immune to malaria. Nevertheless, conflicting results have been obtained in determining whether this antibody specificity correlates with protection in residents of areas where malaria is endemic. In this study, we examined sera collected from a population of semi-immune individuals living in an area of Vietnam with meso-endemicity during a 6-month period. We used two Plasmodium falciparum parasite lines that express either endogenous MSP1(19) or the homologous region from Plasmodium yoelii to measure the MSP1(19)-specific inhibitory activity. We showed that (i) the level of MSP1(19)-specific inhibitory antibodies was not associated with a delay in P. falciparum infection, (ii) MSP1(19)-specific inhibitory antibodies declined significantly during the convalescent period after infection, and (iii) there was no significant correlation between the MSP1(19)-specific inhibitory antibodies and the total antibodies measured by enzyme-linked immunosorbent assay. These results have implications for understanding naturally acquired immunity to malaria and for the development and evaluation of MSP1(19)-based vaccines.
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