1
|
Zhang M, Wang Y, Shen HM, Chen SB, Wang TY, Kassegne K, Chen JH. Genetic Diversity and Natural Selection of Plasmodium vivax Merozoite Surface Protein 8 in Global Populations. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 122:105605. [PMID: 38759940 DOI: 10.1016/j.meegid.2024.105605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 05/09/2024] [Accepted: 05/14/2024] [Indexed: 05/19/2024]
Abstract
Plasmodium vivax Merozoite Surface Protein 8 (PvMSP8) is a promising candidate target for the development of multi-component vaccines. Therefore, determining the genetic variation pattern of Pvmsp8 is essential in providing a reference for the rational design of the P. vivax malaria vaccines. This study delves into the genetic characteristics of the Pvmsp8 gene, specifically focusing on samples from the China-Myanmar border (CMB) region, and contrasts these findings with broader global patterns. The study uncovers that Pvmsp8 exhibits a notable level of conservation across different populations, with limited polymorphisms and relatively low nucleotide diversity (0.00023-0.00120). This conservation contrasts starkly with the high polymorphisms found in other P. vivax antigens such as Pvmsp1. A total of 25 haplotypes and 14 amino acid mutation sites were identified in the global populations, and all mutation sites were confined to non-functional regions. The study also notes that most CMB Pvmsp8 haplotypes are shared among Burmese, Cambodian, Thai, and Vietnamese populations, indicating less geographical variance, but differ notably from those found in Pacific island regions or the Panama. The findings underscore the importance of considering regional genetic diversity in P. vivax when developing targeted malaria vaccines. Non departure from neutral evolution were found by Tajima's D test, however, statistically significant differences were observed between the kn/ks rates. The study's findings are crucial in understanding the evolution and population structure of the Pvmsp8 gene, particularly during regional malaria elimination efforts. The highly conserved nature of Pvmsp8, combined with the lack of mutations in its functional domain, presents it as a promising candidate for developing a broad and effective P. vivax vaccine. This research thus lays a foundation for the rational development of multivalent malaria vaccines targeting this genetically stable antigen.
Collapse
Affiliation(s)
- Man Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases; National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology; World Health Organization (WHO) Collaborating Center for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai 200025, People's Republic of China
| | - Yue Wang
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou 310013, People's Republic of China
| | - Hai-Mo Shen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases; National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology; World Health Organization (WHO) Collaborating Center for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai 200025, People's Republic of China
| | - Shen-Bo Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases; National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology; World Health Organization (WHO) Collaborating Center for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai 200025, People's Republic of China
| | - Tian-Yu Wang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases; National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology; World Health Organization (WHO) Collaborating Center for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai 200025, People's Republic of China
| | - Kokouvi Kassegne
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases; National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology; World Health Organization (WHO) Collaborating Center for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai 200025, People's Republic of China; School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases; National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology; World Health Organization (WHO) Collaborating Center for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai 200025, People's Republic of China; School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou 310013, People's Republic of China; School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China; Hainan Tropical Diseases Research Center (Hainan Sub-Center, Chinese Center for Tropical Diseases Research), Haikou 571199, China.
| |
Collapse
|
2
|
Devi SB, Kumar S. Designing a multi-epitope chimeric protein from different potential targets: A potential vaccine candidate against Plasmodium. Mol Biochem Parasitol 2023; 255:111560. [PMID: 37084957 DOI: 10.1016/j.molbiopara.2023.111560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/23/2023]
Abstract
Malaria is an infectious disease that has been a continuous threat to mankind since the time immemorial. Owing to the complex multi-staged life cycle of the plasmodium parasite, an effective malaria vaccine which is fully protective against the parasite infection is urgently needed to deal with the challenges. In the present study, essential parasite proteins were identified and a chimeric protein with multivalent epitopes was generated. The designed chimeric protein consists of best potential B and T cell epitopes from five different essential parasite proteins. Physiochemical studies of the chimeric protein showed that the modeled vaccine construct was thermo-stable, hydrophilic and antigenic in nature. And the binding of the vaccine construct with Toll-like receptor-4 (TLR-4) as revealed by the molecular docking suggests the possible interaction and role of the vaccine construct in activating the innate immune response. The constructed vaccine being a chimeric protein containing epitopes from different potential candidates could target different stages or pathways of the parasite. Moreover, the approach used in this study is time and cost effective, and can be applied in the discoveries of new potential vaccine targets for other pathogens.
Collapse
Affiliation(s)
- Sanasam Bijara Devi
- Department of Life science & Bioinformatics, Assam University, Silchar 788011 India.
| | - Sanjeev Kumar
- Department of Life science & Bioinformatics, Assam University, Silchar 788011 India
| |
Collapse
|
3
|
Zhang CL, Zhou HN, Liu Q, Yang YM. Genetic polymorphism of merozoite surface proteins 1 and 2 of Plasmodium falciparum in the China-Myanmar border region. Malar J 2019; 18:367. [PMID: 31744492 PMCID: PMC6862846 DOI: 10.1186/s12936-019-3003-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/11/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Malaria is a major public health problem in the China-Myanmar border region. The genetic structure of malaria parasite may affect its transmission model and control strategies. The present study was to analyse genetic diversity of Plasmodium falciparum by merozoite surface proteins 1 and 2 (MSP1 and MSP2) and to determine the multiplicity of infection in clinical isolates in the China-Myanmar border region. METHODS Venous blood samples (172) and filter paper blood spots (70) of P. falciparum isolates were collected from the patients of the China-Myanmar border region from 2006 to 2011. The genomic DNA was extracted, and the msp1 and msp2 genes were genotyped by nested PCR using allele-specific primers for P. falciparum. RESULTS A total of 215 P. falciparum clinical isolates were genotyped at the msp1 (201) and msp2 (204), respectively. For the msp1 gene, MAD20 family was dominant (53.49%), followed by the K1 family (44.65%), and the RO33 family (12.56%). For the msp2 gene, the most frequent allele was the FC27 family (80.93%), followed by the 3D7 family (75.81%). The total multiplicity of infection (MOI) of msp1 and msp2 was 1.76 and 2.21, with a prevalence of 64.19% and 72.09%, respectively. A significant positive correlation between the MOI and parasite density was found in the msp1 gene of P. falciparum. Sequence analysis revealed 38 different alleles of msp1 (14 K1, 23 MAD20, and 1 RO33) and 52 different alleles of msp2 (37 3D7 and 15 FC27). CONCLUSION The present study showed the genetic polymorphisms with diverse allele types of msp1 and msp2 as well as the high MOI of P. falciparum clinical isolates in the China-Myanmar border region.
Collapse
Affiliation(s)
- Cang-Lin Zhang
- Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Yunnan Institute of Parasitic Diseases, Pu'er, 665000, Yunnan, China
| | - Hong-Ning Zhou
- Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Yunnan Institute of Parasitic Diseases, Pu'er, 665000, Yunnan, China
| | - Quan Liu
- School of Life Sciences and Engineering, Foshan University, Foshan, 528225, Guangdong, China.
- Key Laboratory of Organ Regeneration & Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, 130021, China.
| | - Ya-Ming Yang
- Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Yunnan Institute of Parasitic Diseases, Pu'er, 665000, Yunnan, China.
| |
Collapse
|
4
|
Sanasam BD, Kumar S. In-silico structural modeling and epitope prediction of highly conserved Plasmodium falciparum protein AMR1. Mol Immunol 2019; 116:131-139. [PMID: 31648168 DOI: 10.1016/j.molimm.2019.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/29/2019] [Accepted: 10/01/2019] [Indexed: 11/17/2022]
Abstract
Malaria caused by Plasmodium falciparum is the most deadly and a major health issue worldwide. In spite of several control programs, there hasn't been much improvement in keeping the disease under control. The appearance of drug resistant strains of Plasmodium in addition to insecticide resistance of the Anopheles vector has been a hurdle. Therefore, it is highly desirable to identify new potential candidates that can be targeted for therapeutic intervention. The present study identifies AMR1, a highly conserved essential protein of Plasmodium falciparum, as a potential candidate for vaccine development. AMR1 is an exposed surface protein with high antigenic property and conservancy among other species of the parasite. Reverse vaccinology approach (RV) is adopted to determine the best epitopes of AMR1 protein. The protein was further evaluated for several important physiochemical parameters. The study revealed the 3D structure of AMR1, as well as the best B cell and helper T-cell epitopes of the protein. These resulted epitopes might be of great importance in the development of an effective vaccine to combat the deadly disease.
Collapse
Affiliation(s)
- Bijara Devi Sanasam
- Department of Life science & Bioinformatics, Assam University, Silchar, 788011, India
| | - Sanjeev Kumar
- Department of Life science & Bioinformatics, Assam University, Silchar, 788011, India.
| |
Collapse
|
5
|
Salinas ND, Tang WK, Tolia NH. Blood-Stage Malaria Parasite Antigens: Structure, Function, and Vaccine Potential. J Mol Biol 2019; 431:4259-4280. [PMID: 31103771 DOI: 10.1016/j.jmb.2019.05.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/22/2019] [Accepted: 05/08/2019] [Indexed: 10/26/2022]
Abstract
Plasmodium parasites are the causative agent of malaria, a disease that kills approximately 450,000 individuals annually, with the majority of deaths occurring in children under the age of 5 years and the development of a malaria vaccine is a global health priority. Plasmodium parasites undergo a complex life cycle requiring numerous diverse protein families. The blood stage of parasite development results in the clinical manifestation of disease. A vaccine that disrupts the blood stage is highly desired and will aid in the control of malaria. The blood stage comprises multiple steps: invasion of, asexual growth within, and egress from red blood cells. This review focuses on blood-stage antigens with emphasis on antigen structure, antigen function, neutralizing antibodies, and vaccine potential.
Collapse
Affiliation(s)
- Nichole D Salinas
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD,, 20892, USA
| | - Wai Kwan Tang
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD,, 20892, USA
| | - Niraj H Tolia
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD,, 20892, USA.
| |
Collapse
|
6
|
Rodrigues-da-Silva RN, Correa-Moreira D, Soares IF, de-Luca PM, Totino PRR, Morgado FN, Oliveira Henriques MDGD, Peixoto Candea AL, Singh B, Galinski MR, Moreno A, Oliveira-Ferreira J, Lima-Junior JDC. Immunogenicity of synthetic peptide constructs based on PvMSP9 E795-A808, a linear B-cell epitope of the P. vivax Merozoite Surface Protein-9. Vaccine 2018; 37:306-313. [PMID: 30509693 DOI: 10.1016/j.vaccine.2018.10.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 09/26/2018] [Accepted: 10/04/2018] [Indexed: 11/17/2022]
Abstract
Plasmodium vivax Merozoite Surface Protein-9 (PvMSP-9) is a malaria vaccine candidate naturally immunogenic in humans and able to induce high antibody titers in animals when delivered as a recombinant protein. Recently, we identified the sequence EAAPENAEPVHENA (PvMSP9E795-A808) as the main linear B-cell epitope in naturally exposed individuals. However, the potential of PvMSP9E795-A808 as an immunogen in experimental animal models remained unexplored. Here we assess the immunogenicity of PvMSP9E795-A808 using synthetic peptides. The peptides tested in BALB/c mice include two repeats of the sequence EAAPENAEPVHENA tested alone (peptide RII), or linked to an autologous (PvMSP9 peptide pL; pLRII) or heterologous (p2 tetanus toxin universal T cell epitope; TTRII) T cell epitope. Immune responses were evaluated by ELISA, FLUOROSPOT, and indirect immunofluorescence. We show that all of the peptide constructs tested were immunogenic eliciting specific IgG antibodies at different levels, with a prevalence of IgG1 and IgG2. Animals immunized with synthetic peptides containing T cell epitopes (pLRII or TTRII) had more efficient antibody responses that resulted in higher antibody titers able to recognize the native protein by immunofluorescence. Relevantly, the frequency of IFN-γ secreting SFC elicited by immunization with TTRII synthetic peptide was comparable to that reported to the PvMSP9-Nt recombinant protein. Taken together, our study indicates that PvMSP9E795-A808 is highly immunogenic in mice and further studies to evaluate its value as promising vaccine target are warranted. Moreover, our study supports the critical role of CD4 T cell epitopes to enhance humoral responses induced by subunit based vaccines.
Collapse
Affiliation(s)
| | - Daniely Correa-Moreira
- Laboratory of Taxonomy, Biochemistry and Fungi Bioprospecting, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Isabela Ferreira Soares
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Paula Melo de-Luca
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Paulo Renato Rivas Totino
- Laboratory of Malaria Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Fernanda Nazaré Morgado
- Laboratory of Leishmaniasis Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | | | | | - Balwan Singh
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Mary R Galinski
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Division of Infectious Diseases, Emory Vaccine Center, Yerkes National Primate Research Center, Emory University School of Medicine, Emory University, Atlanta, GA, USA
| | - Alberto Moreno
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Division of Infectious Diseases, Emory Vaccine Center, Yerkes National Primate Research Center, Emory University School of Medicine, Emory University, Atlanta, GA, USA
| | - Joseli Oliveira-Ferreira
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Josué da Costa Lima-Junior
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil.
| |
Collapse
|
7
|
Onkoba N, Mumo RM, Ochanda H, Omwandho C, Ozwara HS, Egwang TG. Safety, immunogenicity, and cross-species protection of a plasmid DNA encoding Plasmodium falciparum SERA5 polypeptide, microbial epitopes and chemokine genes in mice and olive baboons. J Biomed Res 2017; 31:321-332. [PMID: 28808204 PMCID: PMC5548993 DOI: 10.7555/jbr.31.20160025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 12/29/2016] [Indexed: 11/03/2022] Open
Abstract
Incorporation of biomolecular epitopes to malarial antigens should be explored in the development of strain-transcending malarial vaccines. The present study sought to determine safety, immunogenicity and cross-species efficacy ofPlasmodium falciparum serine repeat antigen 5 polypeptide co-expressed with epitopes of Bacille-Calmette Guerin (BCG), tetanus toxoid (TT) and a chemokine gene. Olive baboons and BALB/c mice were randomly assigned into vaccine and control groups. The vaccine group animals were primed and boosted twice with pIRES plasmids encoding the SERA5+ BCG+ TT alone, or with either CCL5 or CCL20 and the control group with pIRES plasmid vector backbone. Mice and baboons were challenged withP. berghei ANKA and P. knowlesi H strain parasites, respectively. Safety was determined by observing for injection sites reactogenicities, hematology and clinical chemistry. Parasitaemia and survivorship profiles were used to determine cross-species efficacy, and T cell phenotypes, Th1-, Th2-type, T-regulatory immune responses and antibody responses were assessed to determine vaccine immunogenicity. The pSeBCGTT plasmid DNA vaccines were safe and induced Th1-, Th2-type, and T-regulatory responses vaccinated animals showed enhanced CD4+ (P<0.01), CD 8+ T cells (P<0.001) activation and IgG anti-SE36 antibodies responses (P<0.001) at week 4 and 8 post vaccination compared to the control group. Vaccinated mice had a 31.45-68.69% cumulative parasite load reduction and 60% suppression in baboons (P<0.05) and enhanced survivorship (P<0.001) with no clinical signs of malaria compared to the control group. The results showed that the vaccines were safe, immunogenic and conferred partial cross-species protection.
Collapse
Affiliation(s)
- Nyamongo Onkoba
- . Department of Tropical & Infectious Diseases, Institute of Primate Research, Nairobi P. O. Box 24481-00502, Kenya
- . School of Biological Sciences, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
| | - Ruth M. Mumo
- . Department of Tropical & Infectious Diseases, Institute of Primate Research, Nairobi P. O. Box 24481-00502, Kenya
- . Department of Biochemistry, School of Medicine, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
| | - Horace Ochanda
- . School of Biological Sciences, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
| | - Charles Omwandho
- . Department of Biochemistry, School of Medicine, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
- . Kirinyaga University College, Kerugoya P. O. Box 143-10300, Kenya
| | - Hastings S. Ozwara
- . Department of Tropical & Infectious Diseases, Institute of Primate Research, Nairobi P. O. Box 24481-00502, Kenya
| | | |
Collapse
|
8
|
Rodrigues-da-Silva RN, Martins da Silva JH, Singh B, Jiang J, Meyer EVS, Santos F, Banic DM, Moreno A, Galinski MR, Oliveira-Ferreira J, Lima-Junior JDC. In silico Identification and Validation of a Linear and Naturally Immunogenic B-Cell Epitope of the Plasmodium vivax Malaria Vaccine Candidate Merozoite Surface Protein-9. PLoS One 2016; 11:e0146951. [PMID: 26788998 PMCID: PMC4720479 DOI: 10.1371/journal.pone.0146951] [Citation(s) in RCA: 16] [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: 08/13/2015] [Accepted: 12/22/2015] [Indexed: 12/21/2022] Open
Abstract
Synthetic peptide vaccines provide the advantages of safety, stability and low cost. The success of this approach is highly dependent on efficient epitope identification and synthetic strategies for efficacious delivery. In malaria, the Merozoite Surface Protein-9 of Plasmodium vivax (PvMSP9) has been considered a vaccine candidate based on the evidence that specific antibodies were able to inhibit merozoite invasion and recombinant proteins were highly immunogenic in mice and humans. However the identities of linear B-cell epitopes within PvMSP9 as targets of functional antibodies remain undefined. We used several publicly-available algorithms for in silico analyses and prediction of relevant B cell epitopes within PMSP9. We show that the tandem repeat sequence EAAPENAEPVHENA (PvMSP9E795-A808) present at the C-terminal region is a promising target for antibodies, given its high combined score to be a linear epitope and located in a putative intrinsically unstructured region of the native protein. To confirm the predictive value of the computational approach, plasma samples from 545 naturally exposed individuals were screened for IgG reactivity against the recombinant PvMSP9-RIRII729-972 and a synthetic peptide representing the predicted B cell epitope PvMSP9E795-A808. 316 individuals (58%) were responders to the full repetitive region PvMSP9-RIRII, of which 177 (56%) also presented total IgG reactivity against the synthetic peptide, confirming it validity as a B cell epitope. The reactivity indexes of anti-PvMSP9-RIRII and anti-PvMSP9E795-A808 antibodies were correlated. Interestingly, a potential role in the acquisition of protective immunity was associated with the linear epitope, since the IgG1 subclass against PvMSP9E795-A808 was the prevalent subclass and this directly correlated with time elapsed since the last malaria episode; however this was not observed in the antibody responses against the full PvMSP9-RIRII. In conclusion, our findings identified and experimentally confirmed the potential of PvMSP9E795-A808 as an immunogenic linear B cell epitope within the P. vivax malaria vaccine candidate PvMSP9 and support its inclusion in future subunit vaccines.
Collapse
Affiliation(s)
| | | | - Balwan Singh
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States of America
| | - Jianlin Jiang
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States of America
| | - Esmeralda V. S. Meyer
- Environmental Health and Safety Office, Emory University, Atlanta, GA, United States of America
| | - Fátima Santos
- National Health Foundation, Department of Entomology, Central Laboratory, Porto Velho, RO, Brazil
| | - Dalma Maria Banic
- Laboratory of Simulids and Onchocerciasis "Malaria and Onchocerciasis Research", Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Alberto Moreno
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States of America
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Mary R. Galinski
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States of America
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Emory University, Atlanta, GA, United States of America
| | - Joseli Oliveira-Ferreira
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ, Brazil
- * E-mail: (JCLJ); (JO-F)
| | - Josué da Costa Lima-Junior
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ, Brazil
- * E-mail: (JCLJ); (JO-F)
| |
Collapse
|
9
|
Richie TL. Malaria vaccines for travelers. Travel Med Infect Dis 2012; 2:193-210. [PMID: 17291981 DOI: 10.1016/j.tmaid.2004.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Accepted: 07/07/2004] [Indexed: 11/21/2022]
Affiliation(s)
- Thomas L Richie
- Naval Medical Research Center Malaria Program, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA
| |
Collapse
|
10
|
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.
Collapse
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.
| | | | | | | |
Collapse
|
11
|
Haghi AM, Khoramizade MR, Nateghpour M, Mohebali M, Edrissian GH, Eshraghian MR, Sepehrizadeh Z. A recombinant Plasmodium vivax apical membrane antigen-1 to detect human infection in Iran. THE KOREAN JOURNAL OF PARASITOLOGY 2012; 50:15-21. [PMID: 22451729 PMCID: PMC3309046 DOI: 10.3347/kjp.2012.50.1.15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 12/20/2011] [Accepted: 01/07/2012] [Indexed: 11/23/2022]
Abstract
In Iran, Plasmodium vivax is responsible for more than 80% of the infected cases of malaria per year. Control interventions for vivax malaria in humans rely mainly on developed diagnostic methods. Recombinant P. vivax apical membrane antigen-1 (rPvAMA-1) has been reported to achieve designing rapid, sensitive, and specific molecular diagnosis. This study aimed to perform isolation and expression of a rPvAMA-1, derived from Iranian patients residing in an endemic area. Then, the diagnostic efficiency of the characterized Iranian PvAMA-1 was assessed using an indirect ELISA method. For this purpose, a partial region of AMA-1 gene was amplified, cloned, and expressed in pET32a plasmid. The recombinant His-tagged protein was purified and used to coat the ELISA plate. Antibody detection was assessed by indirect ELISA using rPvAMA-1. The validity of the ELISA method for detection of anti-P. vivax antibodies in the field was compared to light microscopy on 84 confirmed P. vivax patients and compared to 84 non-P. vivax infected individuals. The ELISA cut-off value was calculated as the mean+2SD of OD values of the people living in malaria endemic areas from a south part of Iran. We found a cut-off point of OD=0.311 that showed the best correlation between the sera confirmed with P. vivax infection and healthy control sera. A sensitivity of 81.0% and specificity of 84.5% were found at this cut off titer. A good degree of statistical agreement was found between ELISA using rPvAMA-1 and light microscopy (0.827) by Kappa analysis.
Collapse
Affiliation(s)
- Afsaneh Motevalli Haghi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | | | | | | | | |
Collapse
|
12
|
Siddiqui AJ, Bhardwaj J, Puri SK. mRNA expression of cytokines and its impact on outcomes after infection with lethal and nonlethal Plasmodium vinckei parasites. Parasitol Res 2011; 110:1517-24. [PMID: 21965043 DOI: 10.1007/s00436-011-2656-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Accepted: 09/12/2011] [Indexed: 12/27/2022]
Abstract
Cytokines play an important role in the defense against malaria and some have long been documented to influence the course of malaria infection in rodents and humans. The present study was conducted to determine the mRNA expression pattern of a few prominent cytokines at different time points during the course of infection with a nonlethal and lethal Plasmodium vinckei rodent malaria parasite, using highly sensitive real-time PCR. Analysis of mRNA expression of cytokines in spleen from infected mice revealed that the principal difference was an early depletion in pro-inflammatory cytokine's mRNA expression in mice infected with lethal P. vinckei (PvAS) parasites. In addition, an increase in anti-inflammatory cytokines particularly IL-10 mRNA expression levels was found in the same group of mice. In contrast, the significant rise in pro-inflammatory cytokine's mRNA expression levels was recorded at day 1 onwards after infection with nonlethal P. vinckei (PvAR). The maximum fold change was recorded for IFN-γ and IL-10, when compared to baseline value. TGF-β did not seem to play any major role in P. vinckei infection.
Collapse
Affiliation(s)
- Arif J Siddiqui
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226001, India
| | | | | |
Collapse
|
13
|
Valencia SH, Rodríguez DC, Acero DL, Ocampo V, Arévalo-Herrera M. Platform for Plasmodium vivax vaccine discovery and development. Mem Inst Oswaldo Cruz 2011; 106 Suppl 1:179-92. [PMID: 21881773 PMCID: PMC4832982 DOI: 10.1590/s0074-02762011000900023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 06/15/2011] [Indexed: 01/17/2023] Open
Abstract
Plasmodium vivax is the most prevalent malaria parasite on the American continent. It generates a global burden of 80-100 million cases annually and represents a tremendous public health problem, particularly in the American and Asian continents. A malaria vaccine would be considered the most cost-effective measure against this vector-borne disease and it would contribute to a reduction in malaria cases and to eventual eradication. Although significant progress has been achieved in the search for Plasmodium falciparum antigens that could be used in a vaccine, limited progress has been made in the search for P. vivax components that might be eligible for vaccine development. This is primarily due to the lack of in vitro cultures to serve as an antigen source and to inadequate funding. While the most advanced P. falciparum vaccine candidate is currently being tested in Phase III trials in Africa, the most advanced P. vivax candidates have only advanced to Phase I trials. Herein, we describe the overall strategy and progress in P. vivax vaccine research, from antigen discovery to preclinical and clinical development and we discuss the regional potential of Latin America to develop a comprehensive platform for vaccine development.
Collapse
|
14
|
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.
Collapse
|
15
|
Bagai U, Pawar A, Kumar V. Antibody responses to 43 and 48 kDa antigens of blood-stage Plasmodium berghei in Balb/c mice. J Parasit Dis 2010; 34:68-74. [PMID: 21966123 DOI: 10.1007/s12639-010-0012-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 08/31/2010] [Indexed: 11/29/2022] Open
Abstract
Progress towards a vaccine against malaria is advancing rapidly with several candidate antigens being tested for their safety and efficacy. In present investigation, two polypeptides (43 and 48 kDa) of Plasmodium berghei (NK-65) were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Immunogenicity and protective efficacy of both these polypeptides formulated in saponin has been compared in Balb/c mice against challenge infection with P. berghei. Antibody responses were evaluated by indirect fluorescent antibody test and enzyme-linked immunosorbent assay. Merozoite invasion inhibition assay and challenge infections revealed that 48 kDa antigen is better immunogen as compared to 43 kDa and provide better protection against rodent malaria infection.
Collapse
Affiliation(s)
- Upma Bagai
- Parasitology Laboratory, Department of Zoology, Panjab University, Chandigarh, 160014 India
| | | | | |
Collapse
|
16
|
Protective immune responses elicited by immunization with a chimeric blood-stage malaria vaccine persist but are not boosted by Plasmodium yoelii challenge infection. Vaccine 2010; 28:6876-84. [PMID: 20709001 DOI: 10.1016/j.vaccine.2010.08.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 07/17/2010] [Accepted: 08/02/2010] [Indexed: 11/20/2022]
Abstract
An efficacious malaria vaccine remains elusive despite concerted efforts. Using the Plasmodium yoelii murine model, we previously reported that immunization with the C-terminal 19 kDa domain of merozoite surface protein 1 (MSP1(19)) fused to full-length MSP8 protected against lethal P. yoelii 17XL, well beyond that achieved by single or combined immunizations with the component antigens. Here, we continue the evaluation of the chimeric PyMSP1/8 vaccine. We show that immunization with rPyMSP1/8 vaccine elicited an MSP8-restricted T cell response that was sufficient to provide help for both PyMSP1(19) and PyMSP8-specific B cells to produce high and sustained levels of protective antibodies. The enhanced efficacy of immunization with rPyMSP1/8, in comparison to a combined formulation of rPyMSP1(42) and rPyMSP8, was not due to improved conformation of protective B cell epitopes in the chimeric molecule. Unexpectedly, rPyMSP1/8 vaccine-induced antibody responses were not boosted by exposure to P. yoelii 17XL infected RBCs. However, rPyMSP1/8 immunized and infected mice mounted robust responses to a diverse set of blood-stage antigens. The data support the further development of an MSP1/8 chimeric vaccine but also suggest that vaccines that prime for responses to a diverse set of parasite proteins will be required to maximize vaccine efficacy.
Collapse
|
17
|
A novel Plasmodium falciparum erythrocyte binding protein associated with the merozoite surface, PfDBLMSP. Int J Parasitol 2010; 39:763-73. [PMID: 19367830 DOI: 10.1016/j.ijpara.2008.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Proteins on the surface of the merozoite, the invasive form of the malaria parasite Plasmodium falciparum,and those secreted from its apical secretory organelles are promising vaccine candidates against blood stage malaria. In the present study, we have identified a novel parasite protein (PfDBLMSP; Gene IDPF10_0348), that harbors a predicted signal sequence, a central Duffy binding-like (DBL) domain and a secreted polymorphic antigen associated with merozoites (SPAM) domain in its C-terminal half. Transcription and translation of pfdblmsp is up-regulated specifically in schizont stage parasites, similar to other well-chararacterized merozoite proteins involved in invasion of red blood cells (RBCs). PfDBLMSPwas localized on the merozoite surface with a GFP targeting approach using schizont-stage specific expression systems, and by immunofluorescence assays of the endogenous protein. PfDBLMSP expressed on the surface of mammalian cells (COS-7) showed binding with human RBCs and this binding was sensitive to trypsin and neuraminidase treatments. The recombinant proteins corresponding to the DBL and SPAM domains showed reactivity with immune sera from individuals residing in P. falciparum endemic areas. Polymorphism in PfDBLMSP sequences from different P. falciparum strains and field isolates suggested that its DBL domain is under natural immune pressure. Our data on localization and functional assays suggest a possible role of PfDBLMSP in binding of merozoites with erythrocytes during invasion.
Collapse
|
18
|
Hwang SY, Kim SH, Kho WG. Genetic characteristics of polymorphic antigenic markers among Korean isolates of Plasmodium vivax. THE KOREAN JOURNAL OF PARASITOLOGY 2010; 47 Suppl:S51-8. [PMID: 19885335 DOI: 10.3347/kjp.2009.47.s.s51] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 09/28/2009] [Accepted: 09/28/2009] [Indexed: 11/23/2022]
Abstract
Plasmodium vivax, a protozoan malaria parasite of humans, represents a major public health concern in the Republic of Korea (= South Korea). However, little is known about the genetic properties and population structures of the P. vivax isolates circulating in South Korea. This article reviews known polymorphic genetic markers in South Korean isolates of P. vivax and briefly summarizes the current issues surrounding the gene and population structures of this parasite. The critical genetic characteristics of major antigens of the parasite, such as circumsporozoite protein (CSP), merozoite surface protein 1 (MSP-1) and MSP-3, Duffy binding protein (DBP), apical membrane antigen 1 (AMA-1), and GAM-1, are also discussed.
Collapse
Affiliation(s)
- Seung-Young Hwang
- Department of Parasitology, Inje University College of Medicine, Busan 614-735, Korea
| | | | | |
Collapse
|
19
|
Plasmodium falciparum merozoite surface protein 1 (MSP-1)-MSP-3 chimeric protein: immunogenicity determined with human-compatible adjuvants and induction of protective immune response. Infect Immun 2009; 78:872-83. [PMID: 19933832 DOI: 10.1128/iai.00427-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A chimeric gene, MSP-Fu(24), was constructed by genetically coupling immunodominant, conserved regions of the two leading malaria vaccine candidates, Plasmodium falciparum merozoite surface protein 1 (C-terminal 19-kDa region [PfMSP-1(19)]) and merozoite surface protein 3 (11-kDa conserved region [PfMSP-3(11)]). The recombinant MSP-Fu(24) protein was produced in Escherichia coli cells and purified to homogeneity by a two-step purification process with a yield of approximately 30 mg/liter. Analyses of conformational properties of MSP-Fu(24) using PfMSP-1(19)-specific monoclonal antibody showed that the conformational epitopes of PfMSP-1(19) that may be critical for the generation of the antiparasitic immune response remained intact in the fusion protein. Recombinant MSP-Fu(24) was highly immunogenic in mice and in rabbits when formulated with two different human-compatible adjuvants and induced an immune response against both PfMSP-1(19) and PfMSP-3(11). Purified anti-MSP-Fu(24) antibodies showed invasion inhibition of P. falciparum 3D7 and FCR parasites, and this effect was found to be dependent on antibodies specific for the PfMSP-1(19) component. The protective potential of MSP-Fu(24) was demonstrated by in vitro parasite growth inhibition using an antibody-dependent cell inhibition (ADCI) assay with anti-MSP-Fu(24) antibodies. Overall, the antiparasitic activity was mediated by a combination of growth-inhibitory antibodies generated by both the PfMSP-1(19) and PfMSP-3(11) components of the MSP-Fu(24) protein. The antiparasitic activities elicited by anti-MSP-Fu(24) antibodies were comparable to those elicited by antibodies generated with immunization with a physical mixture of two component antigens, PfMSP-1(19) and PfMSP-3(11). The fusion protein induces a protective immune response with human-compatible adjuvants and may form a part of a multicomponent malaria vaccine.
Collapse
|
20
|
Bueno LL, Morais CG, da Silva Soares I, Bouillet LEM, Bruna-Romero O, Fontes CJ, Fujiwara RT, Braga ÉM. Plasmodium vivax recombinant vaccine candidate AMA-1 plays an important role in adaptive immune response eliciting differentiation of dendritic cells. Vaccine 2009; 27:5581-8. [DOI: 10.1016/j.vaccine.2009.07.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 07/06/2009] [Accepted: 07/14/2009] [Indexed: 11/16/2022]
|
21
|
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.
Collapse
Affiliation(s)
- Elke S Bergmann-Leitner
- US Military Malaria Vaccine Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
| | | | | |
Collapse
|
22
|
Flueck C, Frank G, Smith T, Jafarshad A, Nebie I, Sirima SB, Olugbile S, Alonso P, Tanner M, Druilhe P, Felger I, Corradin G. Evaluation of two long synthetic merozoite surface protein 2 peptides as malaria vaccine candidates. Vaccine 2009; 27:2653-61. [DOI: 10.1016/j.vaccine.2009.02.081] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 02/16/2009] [Accepted: 02/25/2009] [Indexed: 11/17/2022]
|
23
|
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.
Collapse
Affiliation(s)
- Kazutoyo Miura
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
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.
Collapse
|
25
|
Iriemenam NC, Khirelsied AH, Nasr A, ElGhazali G, Giha HA, Elhassan A-Elgadir TM, Agab-Aldour AA, Montgomery SM, Anders RF, Theisen M, Troye-Blomberg M, Elbashir MI, Berzins K. Antibody responses to a panel of Plasmodium falciparum malaria blood-stage antigens in relation to clinical disease outcome in Sudan. Vaccine 2008; 27:62-71. [PMID: 18977268 DOI: 10.1016/j.vaccine.2008.10.025] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 10/03/2008] [Accepted: 10/12/2008] [Indexed: 12/31/2022]
Abstract
Despite many intervention programmes aimed at curtailing the scourge, malaria remains a formidable problem of human health. Immunity to asexual blood-stage of Plasmodium falciparum malaria is thought to be associated with protective antibodies of certain immunoglobulin classes and subclasses. We have analysed immunoglobulin G profiles to six leading blood-stage antigens in relation to clinical malaria outcome in a hospital-based study in Sudan. Our results revealed a linear association with anti-AMA-1-IgG1 antibodies in children <5 years and reduced risk of severe malaria, while the responses of the IgG3 antibodies against MSP-2, MSP-3, GLURP in individuals above 5 years were bi-modal. A dominance of IgG3 antibodies in >5 years was also observed. In the final combined model, the highest levels of IgG1 antibodies to AMA-1, GLURP-R0, and the highest levels of IgG3 antibodies to 3D7 MSP-2 were independently associated with protection from clinical malaria. The study provides further support for the potential importance of the studied merozoite vaccine candidate antigens as targets for parasite neutralizing antibody responses of the IgG1 and IgG3 subclasses.
Collapse
Affiliation(s)
- Nnaemeka C Iriemenam
- Department of Immunology, Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Grech K, Chan BHK, Anders RF, Read AF. THE IMPACT OF IMMUNIZATION ON COMPETITION WITHINPLASMODIUMINFECTIONS. Evolution 2008; 62:2359-71. [DOI: 10.1111/j.1558-5646.2008.00438.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
27
|
Curtidor H, Arévalo G, Vanegas M, Vizcaíno C, Patarroyo MA, Forero M, Patarroyo ME. Characterization of Plasmodium falciparum integral membrane protein Pf25-IMP and identification of its red blood cell binding sequences inhibiting merozoite invasion in vitro. Protein Sci 2008; 17:1494-504. [PMID: 18556472 DOI: 10.1110/ps.036251.108] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The identification of proteins present on the surface of Plasmodium falciparum-infected red blood cells as well as of free merozoites has been widely considered as one of the main areas of research in the development of an antimalarial vaccine due to their involvement in the parasite's pathogenesis and invasion mechanisms. Major advances had been accomplished in this area thanks to the analysis of the reported genomic sequence of P. falciparum, allowing for the identification of genes encoding for putative integral membrane proteins. This study reports for the first time the transcription of the MAL8P1.3 gene, which codifies for a 25-kDa integral membrane protein of P. falciparum (FCB-2 strain), namely, Pf25-IMP. Western blot and immunofluorescence assays using goat polyclonal sera indicate that this protein is expressed in erythrocytic asexual blood stages. A highly robust, sensible, and specific receptor-ligand interaction assay allowed identification of two high activity binding peptides (HABPs) derived from Pf25-IMP: 30577 ((41)YKTANENVKLASSLSDRLSR(60)) and 30583 ((161)LNKKTVVRKIAEGLGYTIVF(180)). Both HABPs bound with high affinity to human red blood cells (RBCs), and such binding was susceptible to enzyme treatment with trypsin. A common RBC surface receptor of apparently 48 kDa was found for both HABPs, plus an additional 31-kDa receptor for HABP 30577. HABP 30577 inhibited merozoite invasion in vitro by 73%, while HABP 30583 showed a 59% inhibition at 200 microM concentration. The data suggest a possible role of Pf25-IMP in merozoite invasion to RBCs and support its inclusion in further immunological studies for evaluating its potential as vaccine candidates.
Collapse
|
28
|
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.
Collapse
Affiliation(s)
- Patricia M Petritus
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | | |
Collapse
|
29
|
Identification and characterization of a novel Plasmodium falciparum merozoite apical protein involved in erythrocyte binding and invasion. PLoS One 2008; 3:e1732. [PMID: 18320051 PMCID: PMC2253826 DOI: 10.1371/journal.pone.0001732] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 01/17/2008] [Indexed: 11/19/2022] Open
Abstract
Proteins that coat Plasmodium falciparum merozoite surface and those secreted from its apical secretory organelles are considered promising candidates for the vaccine against malaria. In the present study, we have identified an asparagine rich parasite protein (PfAARP; Gene ID PFD1105w), that harbors a predicted signal sequence, a C-terminal transmembrane region and whose transcription and translation patterns are similar to some well characterized merozoite surface/apical proteins. PfAARP was localized to the apical end of the merozoites by GFP-targeting approach using an inducible, schizont-stage expression system, by immunofluorescence assays using anti-PfAARP antibodies. Immuno-electron microsopic studies showed that PfAARP is localized in the apical ends of the rhoptries in the merozoites. RBC binding assays with PfAARP expressed on COS cells surface showed that it binds to RBCs through its N-terminal region with a receptor on the RBC surface that is sensitive to trypsin and neuraminidase treatments. Sequencing of PfAARP from different P. falciparum strains as well as field isolates showed that the N-terminal region is highly conserved. Recombinant protein corresponding to the N-terminal region of PfAARP (PfAARP-N) was produced in its functional form in E. coli. PfAARP-N showed reactivity with immune sera from individuals residing in P. falciparum endemic area. The anti-PfAARP-N rabbit antibodies significantly inhibited parasite invasion in vitro. Our data on localization, functional assays and invasion inhibition, suggest a role of PfAARP in erythrocyte binding and invasion by the merozoite.
Collapse
|
30
|
Scorza T, Grubb K, Cambos M, Santamaria C, Tshikudi Malu D, Spithill TW. Vaccination with a Plasmodium chabaudi adami multivalent DNA vaccine cross-protects A/J mice against challenge with P. c. adami DK and virulent Plasmodium chabaudi chabaudi AS parasites. Int J Parasitol 2007; 38:819-27. [PMID: 18062974 DOI: 10.1016/j.ijpara.2007.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 10/13/2007] [Accepted: 10/15/2007] [Indexed: 10/22/2022]
Abstract
A current goal of malaria vaccine research is the development of vaccines that will cross-protect against multiple strains of malaria. In the present study, the breadth of cross-reactivity induced by a 30K multivalent DNA vaccine has been evaluated in susceptible A/J mice (H-2a) against infection with the Plasmodium chabaudi adami DK strain and a virulent parasite subspecies, Plasmodium chabaudi chabaudi AS. Immunized A/J mice were significantly protected against infection with both P. c. adami DK (31-40% reduction in cumulative parasitemia) and P. c. chabaudi AS parasites, where a 30-39% reduction in cumulative parasitemia as well as enhanced survival was observed. The 30K vaccine-induced specific IFN-gamma production by splenocytes in response to native antigens from both P. c. chabaudi AS and P. c. adami DK. Specific antibodies reacting with surface antigens expressed on P. c. adami DS and P. c. chabaudi AS infected red blood cells, and with opsonizing properties, were detected. These results suggest that multivalent vaccines encoding conserved antigens can feasibly induce immune cross-reactivity that span Plasmodium strains and subspecies and can protect hosts of distinct major histocompatibility complex haplotypes.
Collapse
Affiliation(s)
- T Scorza
- Department of Biological Sciences, Université du Québec à Montréal, Case postale 8888, Succursale Centre-Ville, Montréal, Quebec, Canada
| | | | | | | | | | | |
Collapse
|
31
|
Weiss WR, Kumar A, Jiang G, Williams J, Bostick A, Conteh S, Fryauff D, Aguiar J, Singh M, O'Hagan DT, Ulmer JB, Richie TL. Protection of rhesus monkeys by a DNA prime/poxvirus boost malaria vaccine depends on optimal DNA priming and inclusion of blood stage antigens. PLoS One 2007; 2:e1063. [PMID: 17957247 PMCID: PMC2031826 DOI: 10.1371/journal.pone.0001063] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Accepted: 09/11/2007] [Indexed: 11/21/2022] Open
Abstract
Background We have previously described a four antigen malaria vaccine consisting of DNA plasmids boosted by recombinant poxviruses which protects a high percentage of rhesus monkeys against Plasmodium knowlesi (Pk) malaria. This is a multi-stage vaccine that includes two pre-erythrocytic antigens, PkCSP and PkSSP2(TRAP), and two erythrocytic antigens, PkAMA-1 and PkMSP-1(42kD). The present study reports three further experiments where we investigate the effects of DNA dose, timing, and formulation. We also compare vaccines utilizing only the pre-erythrocytic antigens with the four antigen vaccine. Methodology In three experiments, rhesus monkeys were immunized with malaria vaccines using DNA plasmid injections followed by boosting with poxvirus vaccine. A variety of parameters were tested, including formulation of DNA on poly-lactic co-glycolide (PLG) particles, varying the number of DNA injections and the amount of DNA, varying the interval between the last DNA injection to the poxvirus boost from 7 to 21 weeks, and using vaccines with from one to four malaria antigens. Monkeys were challenged with Pk sporozoites given iv 2 to 4 weeks after the poxvirus injection, and parasitemia was measured by daily Giemsa stained blood films. Immune responses in venous blood samples taken after each vaccine injection were measured by ELIspot production of interferon-γ, and by ELISA. Conclusions 1) the number of DNA injections, the formulation of the DNA plasmids, and the interval between the last DNA injection and the poxvirus injection are critical to vaccine efficacy. However, the total dose used for DNA priming is not as important; 2) the blood stage antigens PkAMA-1 and PkMSP-1 were able to protect against high parasitemias as part of a genetic vaccine where antigen folding is not well defined; 3) immunization with PkSSP2 DNA inhibited immune responses to PkCSP DNA even when vaccinations were given into separate legs; and 4) in a counter-intuitive result, higher interferon-γ ELIspot responses to the PkCSP antigen correlated with earlier appearance of parasites in the blood, despite the fact that PkCSP vaccines had a protective effect.
Collapse
Affiliation(s)
- Walter R Weiss
- Naval Medical Research Center, Silver Spring, Maryland, United States of America.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
In immunization with Plasmodium falciparum apical membrane antigen 1, the specificity of antibodies depends on the species immunized. Infect Immun 2007; 75:5827-36. [PMID: 17923516 DOI: 10.1128/iai.00593-07] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
At least a million people, mainly African children under 5 years old, still die yearly from malaria, and the burden of disease and death has increased. Plasmodium falciparum apical membrane antigen 1 (PfAMA1) is one of the most promising blood-stage malarial vaccine candidates. However, the allelic polymorphism observed in this protein is a potential stumbling block for vaccine development. To overcome the polymorphism- and strain-specific growth inhibition in vitro, we previously showed in a rabbit model that vaccination with a mixture of two allelic forms of PfAMA1 induced parasite growth-inhibitory antisera against both strains of P. falciparum parasites in vitro. In the present study, we have established that, in contrast to a single-allele protein, the antigen mixture elicits primarily antibodies recognizing antigenic determinants common to the two antigens, as judged by an antigen reversal growth inhibition assay (GIA). We also show that a similar reactivity pattern occurs after immunization of mice. By contrast, sera from rhesus monkeys do not distinguish the two alleles when tested by an enzyme-linked immunosorbent assay or by GIA, regardless of whether the immunogen is a single AMA1 protein or the mixture. This is the first report that a malarial vaccine candidate induced different specificities of functional antibodies depending on the animal species immunized. These observations, as well as data available on human immune responses in areas of endemicity, suggest that polymorphism in the AMA1 protein may not be as formidable a problem for vaccine development as anticipated from studies with rabbits and mice.
Collapse
|
33
|
Westerfeld N, Pluschke G, Zurbriggen R. Optimized Malaria-antigens delivered by immunostimulating reconstituted influenza virosomes. Wien Klin Wochenschr 2007; 118:50-7. [PMID: 17131241 DOI: 10.1007/s00508-006-0684-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Malaria remains a serious cause of morbidity and mortality in millions of individuals each year. The development of widespread resistance of the parasite to drugs as well as resistance of the transmitting mosquito-vector to insecticides in combination with the poor economic situation of many malaria-endemic countries make the development of an effective and inexpensive treatment and prevention a main focus of research. Vaccines remain to be one of the most cost effective and feasible means of disease control and have remarkable success in the control of many infectious disease: eradication of small pox, virtual eradication of polio and the reduction of measles and diphtheria. Next generation vaccines should focus on specific antigens rather than whole inactivated or attenuated pathogens, since the requirements by regulatory authorities concerning safety are becoming more stringent over time. But sub-unit and in particular peptide-based vaccines are poorly immunogenic themselves, and alum represents only a sub-optimal adjuvant for recombinant proteins and synthetic peptides. This emphasizes the need for suitable carrier- and adjuvant systems promoting protective immune responses by delivering protein and peptide antigens in an appropriate conformation. Here, we review the development of a new approach combining peptide-based malaria vaccine candidate antigens with an immune stimulatory carrier-system based on influenza virosomes focusing on the induction of protective antibodies.
Collapse
|
34
|
Parekh FK, Richie TL. Characterization of Immune Reactivity Profiles Using Microarray Technology May Expedite Identification of Candidate Antigens for Next Generation Malaria Vaccines. Clin Chem 2007; 53:1183-5. [PMID: 17582148 DOI: 10.1373/clinchem.2007.087049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
35
|
Richie T. High road, low road? Choices and challenges on the pathway to a malaria vaccine. Parasitology 2007; 133 Suppl:S113-44. [PMID: 17274843 DOI: 10.1017/s0031182006001843] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Malaria causes much physical and economic hardship in endemic countries with billions of people at risk. A vaccine would clearly benefit these countries, reducing the requirement for hospital care and the economic impact of infection. Successful immunization with irradiated sporozoites and the fact that repeated exposure to malaria induces partial immunity to infection and high levels of protection against the clinical manifestations, suggest that a vaccine is feasible. Numerous candidate antigens have been identified but the vaccine, which has been promised to be 'just round the corner' for many years, remains elusive. The factors contributing to this frustratingly slow progress are discussed including gaps in the knowledge of host/parasite biology, methods to induce potent cell-mediated immune responses, the difficulties associated with defining immune correlates of protection and antigen production and delivery. Finally, the use of attenuated organism vaccines is discussed.
Collapse
Affiliation(s)
- T Richie
- Malaria Program, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, Maryland 20910-7500, USA.
| |
Collapse
|
36
|
Tanabe K, Sakihama N, Walliker D, Babiker H, Abdel-Muhsin AMA, Bakote'e B, Ohmae H, Arisue N, Horii T, Rooth I, Färnert A, Björkman A, Ranford-Cartwright L. Allelic dimorphism-associated restriction of recombination in Plasmodium falciparum msp1. Gene 2007; 397:153-60. [PMID: 17574779 DOI: 10.1016/j.gene.2007.04.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 03/09/2007] [Accepted: 04/25/2007] [Indexed: 11/22/2022]
Abstract
Allelic dimorphism is a characteristic feature of the Plasmodium falciparum msp1 gene encoding the merozoite surface protein 1, a strong malaria vaccine candidate. Meiotic recombination is a major mechanism for the generation of msp1 allelic diversity. Potential recombination sites have previously been mapped to specific regions within msp1 (a 5' 1-kb region and a 3' 0.4-kb region) with no evidence for recombination events in a central 3.5-kb region. However, evidence for the lack of recombination events is circumstantial and inconclusive because the number of msp1 sequences analysed is limited, and the frequency of recombination events has not been addressed previously in a high transmission area, where the frequency of meiotic recombination is expected to be high. In the present study, we have mapped potential allelic recombination sites in 34 full-length msp1 sequences, including 24 new sequences, from various geographic origins. We also investigated recombination events in blocks 6 to 16 by population genetic analysis of P. falciparum populations in Tanzania, where malaria transmission is intense. The results clearly provide no evidence of recombination events occurring between the two major msp1 allelic types, K1-type and Mad20-type, in the central region, but do show recombination events occurring throughout the entire gene within sequences of the Mad20-type. Thus, the present study indicates that allelic dimorphism of msp1 greatly affects inter-allelic recombination events, highlighting a unique feature of allelic diversity of P. falciparum msp1.
Collapse
Affiliation(s)
- Kazuyuki Tanabe
- Laboratory of Malariology, International Research Center of Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Cheng XJ, Hayasaka H, Watanabe K, Tao YL, Liu JY, Tsukamoto H, Horii T, Tanabe K, Tachibana H. Production of high-affinity human monoclonal antibody fab fragments to the 19-kilodalton C-terminal merozoite surface protein 1 of Plasmodium falciparum. Infect Immun 2007; 75:3614-20. [PMID: 17452466 PMCID: PMC1932930 DOI: 10.1128/iai.00062-07] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A combinatorial immunoglobulin gene library was constructed from peripheral blood lymphocytes of eight patients infected with Plasmodium falciparum and was screened for the production of human monoclonal antibody Fab fragments to the C-terminal 19-kDa fragment of P. falciparum merozoite surface protein 1 (MSP-1(19)). Three Fab clones recognized recombinant MSP-1(19) under nonreducing conditions. Indirect immunofluorescence microscopy demonstrated that three Fab clones stained the surfaces of late trophozoites/schizonts and merozoites of the FCR3 and 3D7 strains, suggesting the Fabs' reactivities to a conserved epitope. Sequence analysis of the heavy-chain genes revealed that the closest germ line V segments were VH1-8 and VH7-81, with 91% to 98% homology. The closest germ line D segment was D3-10, and the closest germ line J segment was JH4 or JH5, with 90% to 97% homology. In the light-chain genes, the closest germ line V segment was A27 for the Jkappa2, Jkappa4, and Jkappa5 segments. The dissociation constants of these Fab fragments for recombinant MSP-1(19) ranged from 1.09 x 10(-9) to 2.66 x 10(-9) M. The binding of the three Fab fragments to MSP-1(19) was competitively inhibited by the anti-MSP-1(19) mouse monoclonal antibody 12.8, which inhibits erythrocyte invasion by merozoites. However, the human Fab fragment with the highest affinity did not inhibit in vitro growth of P. falciparum. This is the first report of gene analysis and bacterial expression of human monoclonal antibodies to P. falciparum MSP-1(19). The combinatorial immunoglobulin gene library derived from malaria patients provides a potential tool for producing high-affinity human antibodies specific for P. falciparum.
Collapse
Affiliation(s)
- Xun-Jia Cheng
- Department of Infectious Diseases, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Shi Q, Lynch MM, Romero M, Burns JM. Enhanced protection against malaria by a chimeric merozoite surface protein vaccine. Infect Immun 2006; 75:1349-58. [PMID: 17158895 PMCID: PMC1828565 DOI: 10.1128/iai.01467-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 42-kDa processed fragment of Plasmodium falciparum merozoite surface protein 1 (MSP-1(42)) is a prime candidate for a blood-stage malaria vaccine. Merozoite surface protein 8 contains two C-terminal epidermal growth factor (EGF)-like domains that may function similarly to those of MSP-1(42). Immunization with either MSP-1 or MSP-8 induces protection that is mediated primarily by antibodies against conformation-dependent epitopes. In a series of comparative immunogenicity and efficacy studies using the Plasmodium yoelii rodent model, we tested the ability of recombinant P. yoelii MSP-8 (rPyMSP-8) to complement rPyMSP-1-based vaccines. Unlike MSP-1, PyMSP-8-dependent protection required immunization with the full-length protein and was not induced with recombinant antigens that contained only the C-terminal EGF-like domains. Unlike PyMSP-8, the immunogenicity of the PyMSP-1 EGF-like domains was low when present as part of the rPyMSP-1(42) antigen. Immunization with a mixture of rPyMSP-1(42) and rPyMSP-8 further inhibited the antibody response to protective epitopes of rPyMSP-1(42) and did not improve vaccine efficacy. To improve PyMSP-1 immunogenicity, we produced a chimeric antigen containing the EGF-like domains of PyMSP-1 fused to the N terminus of PyMSP-8. Immunization with the chimeric rPyMSP-1/8 antigen induced high and comparable antibody responses against the EGF-like domains of both PyMSP-1 and PyMSP-8. This enhanced MSP-1-specific antibody response and the concurrent targeting of MSP-1 and MSP-8 resulted in improved, nearly complete protection against lethal P. yoelii 17XL malaria. Unexpectedly, immunization with rPyMSP-1/8 failed to protect against challenge infection with reticulocyte-restricted P. yoelii 17X parasites. Overall, these data establish an effective strategy to improve the efficacy of P. falciparum MSP-based vaccines.
Collapse
Affiliation(s)
- Qifang Shi
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
| | - Michelle M. Lynch
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
| | - Margarita Romero
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
| | - James M. Burns
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129
- Corresponding author. Mailing address: Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129. Phone: (215) 991-8490. Fax: (215) 848-2271. E-mail:
| |
Collapse
|
39
|
Palacpac NMQ, Leung BWY, Arisue N, Tanabe K, Sattabongkot J, Tsuboi T, Torii M, Udomsangpetch R, Horii T. Plasmodium vivax serine repeat antigen (SERA) multigene family exhibits similar expression patterns in independent infections. Mol Biochem Parasitol 2006; 150:353-8. [PMID: 16934884 DOI: 10.1016/j.molbiopara.2006.07.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 07/13/2006] [Accepted: 07/14/2006] [Indexed: 11/27/2022]
Affiliation(s)
- Nirianne Marie Q Palacpac
- Department of Molecular Protozoology, Research Institute for Microbial Diseases (BIKEN), Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Lusingu JPA, Jensen ATR, Vestergaard LS, Minja DT, Dalgaard MB, Gesase S, Mmbando BP, Kitua AY, Lemnge MM, Cavanagh D, Hviid L, Theander TG. Levels of plasma immunoglobulin G with specificity against the cysteine-rich interdomain regions of a semiconserved Plasmodium falciparum erythrocyte membrane protein 1, VAR4, predict protection against malarial anemia and febrile episodes. Infect Immun 2006; 74:2867-75. [PMID: 16622225 PMCID: PMC1459698 DOI: 10.1128/iai.74.5.2867-2875.2006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibodies to variant surface antigen have been implicated as mediators of malaria immunity in studies measuring immunoglobulin G (IgG) binding to infected erythrocytes. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important target for these antibodies, but no study has directly linked the presence of PfEMP1 antibodies in children to protection. We measured plasma IgG levels to the cysteine-rich interdomain region 1alpha (CIDR1alpha) of VAR4 (VAR4-CIDR1alpha), a member of a semiconserved PfEMP1 subfamily, by enzyme-linked immunosorbent assay in 561 Tanzanian individuals, who were monitored clinically for 7 months. The participants resided in Mkokola (a high-transmission village where malaria is holoendemic) or Kwamasimba (a moderate-transmission village). For comparison, plasma IgG levels to two merozoite surface protein 1 (MSP1) constructs, MSP1-19 and MSP1 block 2, and a control CIDR1 domain were measured. VAR4-CIDR1alpha antibodies were acquired at an earlier age in Mkokola than in Kwamasimba, but after the age of 10 years the levels were comparable in the two villages. After controlling for age and other covariates, the risk of having anemia at enrollment was reduced in VAR4-CIDR1alpha responders for Mkokola (adjusted odds ratio [AOR], 0.49; 95% confidence interval [CI], 0.29 to 0.88; P = 0.016) and Kwamasimba (AOR, 0.33; 95% CI, 0.16 to 0.68; P = 0.003) villages. The risk of developing malaria fever was reduced among individuals with a measurable VAR4-CIDR1alpha response from Mkokola village (AOR, 0.51; 95% CI, 0.29 to 0.89; P = 0.018) but not in Kwamasimba. Antibody levels to the MSP1 constructs and the control CIDR1alpha domain were not associated with morbidity protection. These data strengthen the concept of developing vaccines based on PfEMP1.
Collapse
Affiliation(s)
- John P A Lusingu
- Centre for Medical Parasitology, Institute for Medical Microbiology and Immunology, University of Copenhagen, Denmark.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Flück C, Schöpflin S, Smith T, Genton B, Alpers MP, Beck HP, Felger I. Effect of the malaria vaccine Combination B on merozoite surface antigen 2 diversity. INFECTION GENETICS AND EVOLUTION 2006; 7:44-51. [PMID: 16647307 DOI: 10.1016/j.meegid.2006.03.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Accepted: 03/20/2006] [Indexed: 12/01/2022]
Abstract
Extensive genetic polymorphism is generally found in Plasmodium falciparum surface antigens. This poses a considerable obstacle to the development of a malaria vaccine. In order to assess possible effects of a polymorphic vaccine, we have analyzed the genetic diversity of parasites collected in the course of a phase 2b field trial of the blood stage vaccine Combination B in Papua New Guinea. The full-length 3D7 allele of the merozoite surface protein 2 (MSP2) was included in Combination B as one of three subunits. Vaccinees had a lower prevalence of parasites carrying a 3D7-type allele (corresponding to that in the vaccine) and selection appeared to favour the alternative FC27-type alleles resulting in a higher incidence of morbid episodes associated with FC27-type parasites. We sequenced MSP2 alleles detected in study participants after vaccination to identify breakthrough genotypes. Extensive genetic diversity of MSP2 was observed in both the repetitive and family-specific domains, but alleles occurring in vaccine recipients were no different from those found in placebo recipients. A phylogenetic analysis showed no clustering of 3D7-type breakthrough infections from vaccine recipients. The repeat unit present in the vaccine molecule occurred in a number of alleles from the trial area and was also observed in vaccinated individuals. Thus the anti-repeat immune response did not lead to elimination of parasites carrying the same repeat unit. We conclude that the conserved epitopes in the family-specific domain were the most important determinants of the vaccine effect against new 3D7-type infections and that the hypervariable domains were not subject to selective effects of the vaccine.
Collapse
Affiliation(s)
- Christian Flück
- Swiss Tropical Institute, Socinstrasse 57, Postfach, CH 4002 Basel, Switzerland
| | | | | | | | | | | | | |
Collapse
|
42
|
Yokoyama N, Okamura M, Igarashi I. Erythrocyte invasion by Babesia parasites: Current advances in the elucidation of the molecular interactions between the protozoan ligands and host receptors in the invasion stage. Vet Parasitol 2006; 138:22-32. [PMID: 16504403 DOI: 10.1016/j.vetpar.2006.01.037] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
During an asexual growth cycle of Babesia parasites in a natural host, the extracellular merozoites invade (i.e., attach to, penetrate, and internalize) the host erythrocytes (RBC) via multiple adhesive interactions of several protozoan ligands with the target receptors on the host cell surface. After internalizing the host RBC, they asexually multiply, egress from the RBC by rupturing the host cells, and then invade the new RBC again. In the invasion stage, several surface-coating molecules of merozoites might be involved in the initial attachment to the RBC, while proteins secreted from apical organelles (rhoptry, microneme, and spherical body) are proposed to play roles mainly in erythrocyte penetration or internalization. On the other hand, several components located on the surface of the RBC, such as sialic acid residues, protease-sensitive proteins, or sulphated glycosaminoglycans, are identified or suspected as the host receptors of erythrocyte invasion by Babesia parasites. The detailed molecular interactions between Babesia merozoites and the host RBC are incompletely understood. In this review, these identified or suspected molecules (protozoan ligands/erythrocyte receptors) are described by especially focusing on Babesia bovis.
Collapse
Affiliation(s)
- Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
| | | | | |
Collapse
|
43
|
Kats LM, Black CG, Proellocks NI, Coppel RL. Plasmodium rhoptries: how things went pear-shaped. Trends Parasitol 2006; 22:269-76. [PMID: 16635585 DOI: 10.1016/j.pt.2006.04.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 03/13/2006] [Accepted: 04/04/2006] [Indexed: 11/29/2022]
Abstract
Plasmodium parasites have three sets of specialised secretory organelles at the apical end of their invasive forms--rhoptries, micronemes and dense granules. The contents of these organelles are responsible for or contribute to host cell invasion and modification, and at least four apical proteins are leading vaccine candidates. Given the unusual nature of Plasmodium invasion, it is not surprising that unique proteins are involved in this process. Nowhere is this more evident than in rhoptries. We have collated data from several recent studies to compile a rhoptry proteome. Discussion is focussed here on rhoptry content and function.
Collapse
Affiliation(s)
- Lev M Kats
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | | | | | | |
Collapse
|
44
|
Abstract
The optimal outcome of a malaria infection is that parasitized cells are killed and degraded without inducing significant pathology. Since much of the pathology of malaria infection can be immune-mediated, this implies that immune responses have to be carefully regulated. The mechanisms by which anti-malarial immune responses are believed to be regulated were discussed at the recent Malaria Immunology Workshop (Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA; February 2005). Potential regulatory mechanisms include regulatory T cells, which have been shown to significantly modify cellular immune responses to various protozoan infections, including leishmania and malaria; neutralising antibodies to pro-inflammatory malarial toxins such as glycosylphosphatidylinositol and haemozoin; and self-regulating networks of effector molecules. Innate and adaptive immune responses are further moderated by the broader immunological environment, which is influenced by both the genetic background of the host and by co-infection with other pathogens. A detailed understanding of the interplay between these different immunoregulatory processes may facilitate the rationale design of vaccines and novel therapeutics.
Collapse
Affiliation(s)
- E M Riley
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | | | | | | |
Collapse
|
45
|
Curtidor H, Ocampo M, Rodríguez LE, López R, García JE, Valbuena J, Vera R, Puentes A, Leiton J, Cortes LJ, López Y, Patarroyo MA, Patarroyo ME. Plasmodium falciparum TryThrA antigen synthetic peptides block in vitro merozoite invasion to erythrocytes. Biochem Biophys Res Commun 2005; 339:888-96. [PMID: 16329993 DOI: 10.1016/j.bbrc.2005.11.089] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Accepted: 11/14/2005] [Indexed: 11/27/2022]
Abstract
Tryptophan-threonine-rich antigen (TryThrA) is a Plasmodium falciparum homologue of Plasmodium yoelii-infected erythrocyte membrane pypAg-1 antigen. pypAg-1 binds to the surface of uninfected mouse erythrocytes and has been used successfully in vaccine studies. The two antigens are characterized by an unusual tryptophan-rich domain, suggesting similar biological properties. Using synthetic peptides spanning the TryThrA sequence and human erythrocyte we have done binding assays to identify possible TryThrA functional regions. We describe four peptides outside the tryptophan-rich domain having high activity binding to normal human erythrocytes. The peptides termed HABPs (high activity binding peptides) are 30884 ((61)LKEKKKKVLEFFENLVLNKKY(80)) located at the N-terminal and 30901 ((401)RKSLEQQFGDNMDKMNKLKKY(420)), 30902 ((421)KKILKFFPLFNYKSDLESIM(440)) and 30913 ((641)DLESTAEQKAEKKGGKAKAKY(660)) located at the C-terminal. Studies with polyclonal goat antiserum against synthetic peptides chosen to represent the whole length of the protein showed that TryThrA has fluorescence pattern similar to PypAg-1 of P. yoelii. All HABPs inhibited merozoite in vitro invasion, suggesting that TryThrA protein may be participating in merozoite-erythrocyte interaction during invasion.
Collapse
Affiliation(s)
- Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia (FIDIC), Universidad Nacional de Colombia, Colombia.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Shibui A, Shiibashi T, Nogami S, Sugano S, Watanabe J. A novel method for development of malaria vaccines using full-length cDNA libraries. Vaccine 2005; 23:4359-66. [PMID: 16005745 DOI: 10.1016/j.vaccine.2005.03.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 10/04/2004] [Accepted: 03/08/2005] [Indexed: 10/25/2022]
Abstract
We describe a novel method to screen malaria DNA vaccine candidates using a full-length cDNA library and a murine malaria infection model. For the development of effective malaria vaccines, much effort has been made with meager success. The completion of genome sequencing of Plasmodium falciparum has provided invaluable information for achieving this goal. We have been studying full-length cDNA libraries of malaria parasites as a part of genome analysis. Mice vaccinated with a DNA vaccine consisting of 2000 pooled clones showed significantly prolonged survival after challenge infection. In addition, spleen cells of vaccinated mice produced augmented levels of IL-2 and IFN-gamma when incubated with the crude parasite antigens, indicating that cellular immunity plays an important role in the protection. This approach will not only form the basis for development of malaria vaccines but will also be applicable to other parasites and pathogenic microorganisms.
Collapse
Affiliation(s)
- Akiko Shibui
- Department of Infectious Immunology, Shinshu University Graduate School of Medicine, Nagano, Japan
| | | | | | | | | |
Collapse
|
47
|
Abstract
The recent infusion of public and private funding for malaria vaccine development has greatly accelerated the pace at which candidate malaria vaccines are entering the clinic. Recent promising results from vaccine trials carried out in malaria-naive and -endemic populations have revealed important insights into what will be required of a successful vaccine. Significant challenges lie ahead, not the least of which is insuring access of a malaria vaccine to the populations that need it most. Creative strategies, strong partnerships with developing countries, industry-like approaches to product development, and political vision and leadership on the part of wealthy nations will be critical to the successful implementation of this important new tool to reduce the intolerable burden of malaria.
Collapse
Affiliation(s)
- W Ripley Ballou
- Clinical Research and Development, GlaxoSmithKline Biologicals, Rixensart, Belgium.
| |
Collapse
|
48
|
Scorza T, Grubb K, Smooker P, Rainczuk A, Proll D, Spithill TW. Induction of strain-transcending immunity against Plasmodium chabaudi adami malaria with a multiepitope DNA vaccine. Infect Immun 2005; 73:2974-85. [PMID: 15845504 PMCID: PMC1087359 DOI: 10.1128/iai.73.5.2974-2985.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2004] [Revised: 11/22/2004] [Accepted: 01/21/2005] [Indexed: 11/20/2022] Open
Abstract
A major goal of current malaria vaccine programs is to develop multivalent vaccines that will protect humans against the many heterologous malaria strains that circulate in endemic areas. We describe a multiepitope DNA vaccine, derived from a genomic Plasmodium chabaudi adami DS DNA expression library of 30,000 plasmids, which induces strain-transcending immunity in mice against challenge with P. c. adami DK. Segregation of this library and DNA sequence analysis identified vaccine subpools encoding open reading frames (ORFs)/peptides of >9 amino acids [aa] (the V9+ pool, 303 plasmids) and >50 aa (V50+ pool, 56 plasmids), respectively. The V9+ and V50+ plasmid vaccine subpools significantly cross-protected mice against heterologous P. c. adami DK challenge, and protection correlated with the induction of both specific gamma interferon production by splenic cells and opsonizing antibodies. Bioinformatic analysis showed that 22 of the V50+ ORFs were polypeptides conserved among three or more Plasmodium spp., 13 of which are predicted hypothetical proteins. Twenty-nine of these ORFs are orthologues of predicted Plasmodium falciparum sequences known to be expressed in the blood stage, suggesting that this vaccine pool encodes multiple blood-stage antigens. The results have implications for malaria vaccine design by providing proof-of-principle that significant strain-transcending immunity can be induced using multiepitope blood-stage DNA vaccines and suggest that both cellular responses and opsonizing antibodies are necessary for optimal protection against P. c. adami.
Collapse
Affiliation(s)
- T Scorza
- Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste.-Anne-De-Bellevue, Quebec, Canada
| | | | | | | | | | | |
Collapse
|
49
|
Rummel T, Batchelder J, Flaherty P, LaFleur G, Nanavati P, Burns JM, Weidanz WP. CD28 costimulation is required for the expression of T-cell-dependent cell-mediated immunity against blood-stage Plasmodium chabaudi malaria parasites. Infect Immun 2004; 72:5768-74. [PMID: 15385476 PMCID: PMC517583 DOI: 10.1128/iai.72.10.5768-5774.2004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mice suppress the parasitemia of acute blood-stage Plasmodium chabaudi malaria by an antibody- or T-cell-dependent cell-mediated mechanism of immunity (AMI and CMI, respectively) or by both mechanisms. To determine whether CD28 costimulation is required for expression of these polar immune responses, we first compared the time courses of P. chabaudi malaria in CD28-deficient (CD28(-/-)) and CD28-intact (CD28(+/+)) mice. Acute infections in both knockout (KO) and control mice followed similar time courses, with the period of descending parasitemia being prolonged approximately 2 weeks in KO mice followed by intermittent low-grade chronic parasitemia. Infected CD28(-/-) mice produced primarily the immunoglobulin M antibody, which upon passive transfer provided partial protection against P. chabaudi challenge, suggesting that the elimination of blood-stage parasites by CD28(-/-) mice was achieved by AMI. To determine whether CD28(-/-) costimulation is required for the expression of CMI against the parasite, we compared the time courses of parasitemia in B-cell-deficient double-KO (J(H)(-/-) x CD28(-/-)) mice and control (J(H)(-/-) x CD28(+/+)) mice. Whereas control mice suppressed parasitemia to subpatent levels within approximately 2 weeks postinoculation, double-KO mice developed high levels of parasitemia of long-lasting duration. Although not required for the suppression of acute P. chabaudi parasitemia by AMI, CD28 costimulation is essential for the elimination of blood-stage parasites by CMI.
Collapse
Affiliation(s)
- Thomas Rummel
- Department of Medical Microbiology and Immunology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA
| | | | | | | | | | | | | |
Collapse
|
50
|
Doolan DL, Aguiar JC, Weiss WR, Sette A, Felgner PL, Regis DP, Quinones-Casas P, Yates JR, Blair PL, Richie TL, Hoffman SL, Carucci DJ. Utilization of genomic sequence information to develop malaria vaccines. J Exp Biol 2003; 206:3789-802. [PMID: 14506214 DOI: 10.1242/jeb.00615] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYRecent advances in the fields of genomics, proteomics and molecular immunology offer tremendous opportunities for the development of novel interventions against public health threats, including malaria. However, there is currently no algorithm that can effectively identify the targets of protective T cell or antibody responses from genomic data. Furthermore, the identification of antigens that will stimulate the most effective immunity against the target pathogen is problematic, particularly if the genome is large. Malaria is an attractive model for the development and validation of approaches to translate genomic information to vaccine development because of the critical need for effective anti-malarial interventions and because the Plasmodium parasite is a complex multistage pathogen targeted by multiple immune responses. Sterile protective immunity can be achieved by immunization with radiation-attenuated sporozoites, and anti-disease immunity can be induced in residents in malaria-endemic areas. However, the 23 Mb Plasmodium falciparum genome encodes more than 5300 proteins, each of which is a potential target of protective immune responses. The current generation of subunit vaccines is based on a single or few antigens and therefore might elicit too narrow a breadth of response. We are working towards the development of a new generation vaccine based on the presumption that duplicating the protection induced by the whole organism may require a vaccine nearly as complex as the organism itself. Here, we present our strategy to exploit the genomic sequence of P. falciparum for malaria vaccine development.
Collapse
Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|