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Metoh TN, Chen JH, Fon-Gah P, Zhou X, Moyou-Somo R, Zhou XN. Genetic diversity of Plasmodium falciparum and genetic profile in children affected by uncomplicated malaria in Cameroon. Malar J 2020; 19:115. [PMID: 32188442 PMCID: PMC7081701 DOI: 10.1186/s12936-020-03161-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/12/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Malaria is a major public health problem in Cameroon. The study of the genetic diversity within parasite population is essential for understanding the mechanism underlying malaria pathology and to determine parasite clones profile in an infection, for proper malaria control strategies. The objective of this study was to perform a molecular characterization of highly polymorphic genetic markers of Plasmodium falciparum, and to determine allelic distribution with their influencing factors valuable to investigate malaria transmission dynamics in Cameroon. METHODS A total of 350 P. falciparum clinical isolates were characterized by genotyping block 2 of msp-1, block 3 of msp-2, and region II of glurp gene using nested PCR and DNA sequencing between 2012 and 2013. RESULTS A total of 5 different genotypes with fragment sizes ranging from 597 to 817 bp were recorded for GLURP. Overall, 16 MSP-1 genotypes, including K1, MAD20 and RO33 were identified, ranging from 153 to 335 bp. A peculiarity about this study is the RO33 monomorphic pattern revealed among the Pfmsp-1 allelic type. Again, this study identified 27 different Pfmsp-2 genotypes, ranging from 140 to 568 bp in size, including 15 belonging to the 3D7-type and 12 to the FC27 allelic families. The analysis of the MSP-1 and MSP-2 peptides indicates that the region of the alignment corresponding K1 polymorphism had the highest similarity in the MSP1and MSP2 clade followed by MAD20 with 93% to 100% homology. Therefore, population structure of P. falciparum isolates is identical to that of other areas in Africa, suggesting that vaccine developed with K1 and MAD20 of Pfmsp1 allelic variant could be protective for Africa children but these findings requires further genetic and immunological investigations. The multiplicity of infection (MOI) was significantly higher (P < 0.05) for Pfmsp-2 loci (3.82), as compare with Pfmsp-1 (2.51) and heterozygotes ranged from 0.55 for Pfmsp-1 to 0.96 for Pfmsp-2. CONCLUSION High genetic diversity and allelic frequencies in P. falciparum isolates indicate a persisting high level of transmission. This study advocate for an intensification of the malaria control strategies in Cameroon. Trial registration This study was approved by Cameroon National Ethics Committee. It is a randomized controlled trial retrospectively registered in NIH U.S. National Library of Medicine, ClinicalTrials.gov on the 28/11/2016 at https://clinicaltrials.gov/ct2/show/NCT02974348 with the registration number NCT02974348.
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Affiliation(s)
- Theresia Njuabe Metoh
- Department of Biochemistry, Faculty of Science, The University of Bamenda, P. O. Box 39 Bambili, Bamenda, Cameroon.
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention, Shanghai, 200025, People's Republic of China.
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China.
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention, Shanghai, 200025, People's Republic of China
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China
| | - Philip Fon-Gah
- ITC Enschede, University of Twenty, Hengelosestraat 99, 7514 AE, Enschede, The Netherlands
- Department of Geoscience-Remote Sensing and GIS, The University of Bamenda, P. O. Box 39 Bambili, Bamenda, Cameroon
| | - Xia Zhou
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention, Shanghai, 200025, People's Republic of China
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China
| | - Roger Moyou-Somo
- Institute of Medical Research and Medicinal Plants-IMPM, P. O. 6123, Yaoundé, Cameroon
- Faculty of Medicines and Biomedical Sciences, The University of Yaoundé I, P. O. Box 812, Yaoundé, Cameroon
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention, Shanghai, 200025, People's Republic of China
- WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China
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Lê HG, Kang JM, Jun H, Lee J, Thái TL, Myint MK, Aye KS, Sohn WM, Shin HJ, Kim TS, Na BK. Changing pattern of the genetic diversities of Plasmodium falciparum merozoite surface protein-1 and merozoite surface protein-2 in Myanmar isolates. Malar J 2019; 18:241. [PMID: 31311565 PMCID: PMC6636015 DOI: 10.1186/s12936-019-2879-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Plasmodium falciparum merozoite surface protein-1 (PfMSP-1) and -2 (PfMSP-2) are major blood-stage vaccine candidate antigens. Understanding the genetic diversity of the genes, pfmsp-1 and pfmsp-2, is important for recognizing the genetic structure of P. falciparum, and the development of an effective vaccine based on the antigens. In this study, the genetic diversities of pfmsp-1 and pfmsp-2 in the Myanmar P. falciparum were analysed. METHODS The pfmsp-1 block 2 and pfmsp-2 block 3 regions were amplified by polymerase chain reaction from blood samples collected from Myanmar patients who were infected with P. falciparum in 2013-2015. The amplified gene fragments were cloned into a T&A vector, and sequenced. Sequence analysis of Myanmar pfmsp-1 block 2 and pfmsp-2 block 3 was performed to identify the genetic diversity of the regions. The temporal genetic changes of both pfmsp-1 and pfmsp-2 in the Myanmar P. falciparum population, as well as the polymorphic diversity in the publicly available global pfmsp-1 and pfmsp-2, were also comparatively analysed. RESULTS High levels of genetic diversity of pfmsp-1 and pfmsp-2 were observed in the Myanmar P. falciparum isolates. Twenty-eight different alleles of pfmsp-1 (8 for K1 type, 14 for MAD20 type, and 6 for RO33 type) and 59 distinct alleles of pfmsp-2 (18 for FC27, and 41 for 3D7 type) were identified in the Myanmar P. falciparum population in amino acid level. Comparative analyses of the genetic diversity of the Myanmar pfmsp-1 and pfmsp-2 alleles in the recent (2013-2015) and past (2004-2006) Myanmar P. falciparum populations indicated the dynamic genetic expansion of the pfmsp-1 and pfmsp-2 in recent years, suggesting that a high level of genetic differentiation and recombination of the two genes may be maintained. Population genetic structure analysis of the global pfmsp-1 and pfmsp-2 also suggested that a high level of genetic diversity of the two genes was found in the global P. falciparum population. CONCLUSION Despite the recent remarkable decline of malaria cases, the Myanmar P. falciparum population still remains of sufficient size to allow the generation and maintenance of genetic diversity. The high level of genetic diversity of pfmsp-1 and pfmsp-2 in the global P. falciparum population emphasizes the necessity for continuous monitoring of the genetic diversity of the genes for better understanding of the genetic make-up and evolutionary aspect of the genes in the global P. falciparum population.
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Affiliation(s)
- Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Hojong Jun
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Jinyoung Lee
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Thị Lam Thái
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Moe Kyaw Myint
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Khin Saw Aye
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea. .,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
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3
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Ghoshal S, Gajendra P, Datta Kanjilal S, Mitra M, Sengupta S. Diversity analysis of MSP1 identifies conserved epitope organization in block 2 amidst high sequence variability in Indian Plasmodium falciparum isolates. Malar J 2018; 17:447. [PMID: 30509263 PMCID: PMC6276175 DOI: 10.1186/s12936-018-2592-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 11/23/2018] [Indexed: 02/02/2023] Open
Abstract
Background Despite its immunogenicity, the polymorphic nature of merozoite surface protein 1, an important vaccine candidate for Plasmodium falciparum malaria, remains a concern. This study analyses the impact of genetic variability and parasite population structure on epitope organization of different MSP1 segments. Methods Altogether 98 blood samples collected from P. falciparum infected mild and severe malaria patients of Chhattisgarh and West Bengal were used to sequence regions encoding block 2 and MSP1-19 of msp1. Sequences were analysed using MEGA7, DnaSPv5, Arlequin3.5 and BepiPred. Results All three major MSP1 block 2 allele families namely K1, MAD20 and RO33 were detected in the samples and they together resulted in 41 indel variants. Chhattisgarh samples displayed an average MOI of 2.07 ± 1.59 which was higher in mild malaria and in age group < 18 years. Ultra-structure of block 2 alleles revealed that mutation and repeat expansion were two major mechanisms responsible for allelic variability of K1 and MAD20. Regions flanking block 2 were highly variable in Chhattisgarh with average mismatch differences (k) ranging from 1.198 to 5.156 for three families. In contrast, region encompassing MSP1-19 exhibited limited heterogeneity (kChhattisgarh = 1.45, kWest Bengal = 1.363). Of the 50 possible B cell linear epitopes predicted from block 2 variants, 94.9% (131 of 138) of the parasites could be represented by three conserved antigens. Conclusions Present data indicates that natural selection and transmission intensity jointly play a role in controlling allelic diversity of MSP1 in Indian parasite isolates. Despite remarkable genetic variability, a limited number of predominant and conserved epitopes are present in Indian parasite isolates reinstating the importance of MSP1 as a promising malaria vaccine candidate. Electronic supplementary material The online version of this article (10.1186/s12936-018-2592-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sharmistha Ghoshal
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700 019, India
| | - Pragya Gajendra
- School of Studies in Anthropology, Pt. Ravishankar Shukla University, Raipur, Chhattisgarh, 492010, India
| | - Sumana Datta Kanjilal
- Department of Pediatric Medicine, Institute of Post Graduate Medical Education & Research, Kolkata, West Bengal, India
| | - Mitashree Mitra
- School of Studies in Anthropology, Pt. Ravishankar Shukla University, Raipur, Chhattisgarh, 492010, India
| | - Sanghamitra Sengupta
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700 019, India.
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Aspeling-Jones H, Conway DJ. An expanded global inventory of allelic variation in the most extremely polymorphic region of Plasmodium falciparum merozoite surface protein 1 provided by short read sequence data. Malar J 2018; 17:345. [PMID: 30285849 PMCID: PMC6167803 DOI: 10.1186/s12936-018-2475-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 09/04/2018] [Indexed: 12/15/2022] Open
Abstract
Background Within Plasmodium falciparum merozoite surface protein 1 (MSP1), the N-terminal block 2 region is a highly polymorphic target of naturally acquired antibody responses. The antigenic diversity is determined by complex repeat sequences as well as non-repeat sequences, grouping into three major allelic types that appear to be maintained within populations by natural selection. Within these major types, many distinct allelic sequences have been described in different studies, but the extent and significance of the diversity remains unresolved. Methods To survey the diversity more extensively, block 2 allelic sequences in the msp1 gene were characterized in 2400 P. falciparum infection isolates with whole genome short read sequence data available from the Pf3K project, and compared with the data from previous studies. Results Mapping the short read sequence data in the 2400 isolates to a reference library of msp1 block 2 allelic sequences yielded 3815 allele scores at the level of major allelic family types, with 46% of isolates containing two or more of these major types. Overall frequencies were similar to those previously reported in other samples with different methods, the K1-like allelic type being most common in Africa, MAD20-like most common in Southeast Asia, and RO33-like being the third most abundant type in each continent. The rare MR type, formed by recombination between MAD20-like and RO33-like alleles, was only seen in Africa and very rarely in the Indian subcontinent but not in Southeast Asia. A combination of mapped short read assembly approaches enabled 1522 complete msp1 block 2 sequences to be determined, among which there were 363 different allele sequences, of which 246 have not been described previously. In these data, the K1-like msp1 block 2 alleles are most diverse and encode 225 distinct amino acid sequences, compared with 123 different MAD20-like, 9 RO33-like and 6 MR type sequences. Within each of the major types, the different allelic sequences show highly skewed geographical distributions, with most of the more common sequences being detected in either Africa or Asia, but not in both. Conclusions Allelic sequences of this extremely polymorphic locus have been derived from whole genome short read sequence data by mapping to a reference library followed by assembly of mapped reads. The catalogue of sequence variation has been greatly expanded, so that there are now more than 500 different msp1 block 2 allelic sequences described. This provides an extensive reference for molecular epidemiological genotyping and sequencing studies, and potentially for design of a multi-allelic vaccine. Electronic supplementary material The online version of this article (10.1186/s12936-018-2475-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Harvey Aspeling-Jones
- Pathogen Molecular Biology Department, School of Hygiene and Tropical Medicine London, Keppel St, London, WC1E 7HT, UK.
| | - David J Conway
- Pathogen Molecular Biology Department, School of Hygiene and Tropical Medicine London, Keppel St, London, WC1E 7HT, UK.
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5
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Patel P, Bharti PK, Bansal D, Raman RK, Mohapatra PK, Sehgal R, Mahanta J, Sultan AA, Singh N. Genetic diversity and antibody responses against Plasmodium falciparum vaccine candidate genes from Chhattisgarh, Central India: Implication for vaccine development. PLoS One 2017; 12:e0182674. [PMID: 28787005 PMCID: PMC5546615 DOI: 10.1371/journal.pone.0182674] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 07/21/2017] [Indexed: 11/22/2022] Open
Abstract
The genetic diversity in Plasmodium falciparum antigens is a major hurdle in developing an effective malaria vaccine. Protective efficacy of the vaccine is dependent on the polymorphic alleles of the vaccine candidate antigens. Therefore, we investigated the genetic diversity of the potential vaccine candidate antigens i.e. msp-1, msp-2, glurp, csp and pfs25 from field isolates of P.falciparum and determined the natural immune response against the synthetic peptide of these antigens. Genotyping was performed using Sanger method and size of alleles, multiplicity of infection, heterogeneity and recombination rate were analyzed. Asexual stage antigens were highly polymorphic with 55 and 50 unique alleles in msp-1 and msp-2 genes, respectively. The MOI for msp-1 and msp-2 were 1.67 and 1.28 respectively. A total 59 genotype was found in glurp gene with 8 types of amino acid repeats in the conserved part of RII repeat region. The number of NANP repeats from 40 to 44 was found among 55% samples in csp gene while pfs25 was found almost conserved with only two amino acid substitution site. The level of genetic diversity in the present study population was very similar to that from Asian countries. A higher IgG response was found in the B-cell epitopes of msp-1 and csp antigens and higher level of antibodies against csp B-cell epitope and glurp antigen were recorded with increasing age groups. Significantly, higher positive responses were observed in the csp antigen among the samples with ≥42 NANP repeats. The present finding showed extensive diversity in the asexual stage antigens.
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Affiliation(s)
- Priyanka Patel
- National Institute for Research in Tribal Health, Indian Council of Medical Research, Garha, Jabalpur, Madhya Pradesh, India
| | - Praveen K. Bharti
- National Institute for Research in Tribal Health, Indian Council of Medical Research, Garha, Jabalpur, Madhya Pradesh, India
| | - Devendra Bansal
- Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University, Qatar Foundation - Education City, Doha, Qatar
| | - Rajive K. Raman
- Community Health Centre Janakpur, District Baikunthpur, Chhattisgarh, India
| | - Pradyumna K. Mohapatra
- Regional Medical Research Centre, NE, Indian Council of Medical Research, Dibrugarh, Assam, India
| | - Rakesh Sehgal
- Department of Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, Punjab, India
| | - Jagadish Mahanta
- Regional Medical Research Centre, NE, Indian Council of Medical Research, Dibrugarh, Assam, India
| | - Ali A. Sultan
- Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University, Qatar Foundation - Education City, Doha, Qatar
| | - Neeru Singh
- National Institute for Research in Tribal Health, Indian Council of Medical Research, Garha, Jabalpur, Madhya Pradesh, India
- * E-mail:
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Adu B, Cherif MK, Bosomprah S, Diarra A, Arthur FKN, Dickson EK, Corradin G, Cavanagh DR, Theisen M, Sirima SB, Nebie I, Dodoo D. Antibody levels against GLURP R2, MSP1 block 2 hybrid and AS202.11 and the risk of malaria in children living in hyperendemic (Burkina Faso) and hypo-endemic (Ghana) areas. Malar J 2016; 15:123. [PMID: 26921176 PMCID: PMC4769494 DOI: 10.1186/s12936-016-1146-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 02/04/2016] [Indexed: 12/31/2022] Open
Abstract
Background
Differences in parasite transmission intensity influence the process of acquisition of host immunity to Plasmodium falciparum malaria and ultimately, the rate of malaria related morbidity and mortality. Potential vaccines being designed to complement current intervention efforts therefore need to be evaluated against different malaria endemicity backgrounds. Methods The associations between antibody responses to the chimeric merozoite surface protein 1 block 2 hybrid (MSP1 hybrid), glutamate-rich protein region 2 (GLURP R2) and the peptide AS202.11, and the risk of malaria were assessed in children living in malaria hyperendemic (Burkina Faso, n = 354) and hypo-endemic (Ghana, n = 209) areas. Using the same reagent lots and standardized protocols for both study sites, immunoglobulin (Ig) M, IgG and IgG sub-class levels to each antigen were measured by ELISA in plasma from the children (aged 6–72 months). Associations between antibody levels and risk of malaria were assessed using Cox regression models adjusting for covariates. Results There was a significant association between GLURP R2 IgG3 and reduced risk of malaria after adjusting age of children in both the Burkinabe (hazard ratio 0.82; 95 % CI 0.74–0.91, p < 0.0001) and the Ghanaian (HR 0.48; 95 % CI 0.25–0.91, p = 0.02) cohorts. MSP1 hybrid IgM was associated (HR 0.85; 95 % CI 0.73–0.98, p = 0.02) with reduced risk of malaria in Burkina Faso cohort while IgG against AS202.11 in the Ghanaian children was associated with increased risk of malaria (HR 1.29; 95 % CI 1.01–1.65, p = 0.04). Conclusion These findings support further development of GLURP R2 and MSP1 block 2 hybrid, perhaps as a fusion vaccine antigen targeting malaria blood stage that can be deployed in areas of varying transmission intensity. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1146-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bright Adu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Mariama K Cherif
- Polytechnic University of BoboDioulasso, Bobo-Dioulasso, Burkina Faso. .,Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso.
| | | | - Amidou Diarra
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso.
| | - Fareed K N Arthur
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Emmanuel K Dickson
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | | | - David R Cavanagh
- Institute of Cell, Animal and Population Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, UK.
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso.
| | - Issa Nebie
- Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso.
| | - Daniel Dodoo
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
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Cowan GJM, Bockau U, Eleni-Muus J, Aldag I, Samuel K, Creasey AM, Hartmann MWW, Cavanagh DR. A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila. PLoS One 2014; 9:e87198. [PMID: 24489871 PMCID: PMC3906136 DOI: 10.1371/journal.pone.0087198] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 12/20/2013] [Indexed: 01/15/2023] Open
Abstract
Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens.
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Affiliation(s)
- Graeme J. M. Cowan
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | | | - Kay Samuel
- Cell Therapy Group, Scottish National Blood Transfusion Service, Edinburgh, United Kingdom
| | - Alison M. Creasey
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | - David R. Cavanagh
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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8
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Cavanagh DR, Kocken CHM, White JH, Cowan GJM, Samuel K, Dubbeld MA, der Wel AVV, Thomas AW, McBride JS, Arnot DE. Antibody responses to a novel Plasmodium falciparum merozoite surface protein vaccine correlate with protection against experimental malaria infection in Aotus monkeys. PLoS One 2014; 9:e83704. [PMID: 24421900 PMCID: PMC3885447 DOI: 10.1371/journal.pone.0083704] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/06/2013] [Indexed: 11/29/2022] Open
Abstract
The Block 2 region of the merozoite surface protein-1 (MSP-1) of Plasmodium falciparum has been identified as a target of protective immunity by a combination of seroepidemiology and parasite population genetics. Immunogenicity studies in small animals and Aotus monkeys were used to determine the efficacy of recombinant antigens derived from this region of MSP-1 as a potential vaccine antigen. Aotus lemurinus griseimembra monkeys were immunized three times with a recombinant antigen derived from the Block 2 region of MSP-1 of the monkey-adapted challenge strain, FVO of Plasmodium falciparum, using an adjuvant suitable for use in humans. Immunofluorescent antibody assays (IFA) against erythrocytes infected with P. falciparum using sera from the immunized monkeys showed that the MSP-1 Block 2 antigen induced significant antibody responses to whole malaria parasites. MSP-1 Block 2 antigen-specific enzyme-linked immunosorbent assays (ELISA) showed no significant differences in antibody titers between immunized animals. Immunized animals were challenged with the virulent P. falciparum FVO isolate and monitored for 21 days. Two out of four immunized animals were able to control their parasitaemia during the follow-up period, whereas two out of two controls developed fulminating parasitemia. Parasite-specific serum antibody titers measured by IFA were four-fold higher in protected animals than in unprotected animals. In addition, peptide-based epitope mapping of serum antibodies from immunized Aotus showed distinct differences in epitope specificities between protected and unprotected animals.
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Affiliation(s)
- David R. Cavanagh
- Institute of Immunology and Infection Research, Center for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Clemens H. M. Kocken
- Biomedical Primate Research Center, Department of Parasitology, Rijswijk, The Netherlands
| | - John H. White
- Institute of Immunology and Infection Research, Center for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Graeme J. M. Cowan
- Institute of Immunology and Infection Research, Center for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Kay Samuel
- Scottish National Blood Transfusion Service, Cell Therapy Group, University of Edinburgh, Edinburgh, United Kingdom
| | - Martin A. Dubbeld
- Biomedical Primate Research Center, Department of Parasitology, Rijswijk, The Netherlands
| | | | - Alan W. Thomas
- Biomedical Primate Research Center, Department of Parasitology, Rijswijk, The Netherlands
| | - Jana S. McBride
- Institute of Immunology and Infection Research, Center for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - David E. Arnot
- Institute of Immunology and Infection Research, Center for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
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Yuan L, Zhao H, Wu L, Li X, Parker D, Xu S, Zhao Y, Feng G, Wang Y, Yan G, Fan Q, Yang Z, Cui L. Plasmodium falciparum populations from northeastern Myanmar display high levels of genetic diversity at multiple antigenic loci. Acta Trop 2013; 125:53-9. [PMID: 23000544 DOI: 10.1016/j.actatropica.2012.09.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/07/2012] [Accepted: 09/12/2012] [Indexed: 11/27/2022]
Abstract
Levels of genetic diversity of the malaria parasites and multiclonal infections are correlated with transmission intensity. In order to monitor the effect of strengthened malaria control efforts in recent years at the China-Myanmar border area, we followed the temporal dynamics of genetic diversity of three polymorphic antigenic markers msp1, msp2, and glurp in the Plasmodium falciparum populations. Despite reduced malaria prevalence in the region, parasite populations exhibited high levels of genetic diversity. Genotyping 258 clinical samples collected in four years detected a total of 22 PCR size alleles. Multiclonal infections were detected in 45.7% of the patient samples, giving a minimum multiplicity of infection of 1.41. The majority of alleles experienced significant temporal fluctuations through the years. Haplotype diversity based on the three-locus genotypes ranged from the lowest in 2009 at 0.33 to the highest in 2010 at 0.80. Sequencing of msp1 fragments from 36 random samples of five allele size groups detected 13 different sequences, revealing an additional layer of genetic complexity. This study suggests that despite reduced prevalence of malaria infections in this region, the parasite population size and transmission intensity remained high enough to allow effective genetic recombination of the parasites and continued maintenance of genetic diversity.
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Affiliation(s)
- Lili Yuan
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan Province, China
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10
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Cowan GJM, Creasey AM, Dhanasarnsombut K, Thomas AW, Remarque EJ, Cavanagh DR. A malaria vaccine based on the polymorphic block 2 region of MSP-1 that elicits a broad serotype-spanning immune response. PLoS One 2011; 6:e26616. [PMID: 22073118 PMCID: PMC3202563 DOI: 10.1371/journal.pone.0026616] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 09/29/2011] [Indexed: 12/28/2022] Open
Abstract
Polymorphic parasite antigens are known targets of protective immunity to malaria, but this antigenic variation poses challenges to vaccine development. A synthetic MSP-1 Block 2 construct, based on all polymorphic variants found in natural Plasmodium falciparum isolates has been designed, combined with the relatively conserved Block 1 sequence of MSP-1 and expressed in E.coli. The MSP-1 Hybrid antigen has been produced with high yield by fed-batch fermentation and purified without the aid of affinity tags resulting in a pure and extremely thermostable antigen preparation. MSP-1 hybrid is immunogenic in experimental animals using adjuvants suitable for human use, eliciting antibodies against epitopes from all three Block 2 serotypes. Human serum antibodies from Africans naturally exposed to malaria reacted to the MSP-1 hybrid as strongly as, or better than the same serum reactivities to individual MSP-1 Block 2 antigens, and these antibody responses showed clear associations with reduced incidence of malaria episodes. The MSP-1 hybrid is designed to induce a protective antibody response to the highly polymorphic Block 2 region of MSP-1, enhancing the repertoire of MSP-1 Block 2 antibody responses found among immune and semi-immune individuals in malaria endemic areas. The target population for such a vaccine is young children and vulnerable adults, to accelerate the acquisition of a full range of malaria protective antibodies against this polymorphic parasite antigen.
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MESH Headings
- Adolescent
- Adult
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Protozoan/blood
- Antibodies, Protozoan/immunology
- Case-Control Studies
- Child
- Child, Preschool
- Cross-Sectional Studies
- Enzyme-Linked Immunosorbent Assay
- Female
- Fluorescent Antibody Technique, Indirect
- Humans
- Immunization
- Immunoblotting
- Immunoglobulin G/immunology
- Macaca mulatta
- Malaria Vaccines/immunology
- Malaria, Falciparum/immunology
- Malaria, Falciparum/prevention & control
- Merozoite Surface Protein 1/immunology
- Mice
- Mice, Inbred DBA
- Plasmodium falciparum/growth & development
- Plasmodium falciparum/immunology
- Rabbits
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Affiliation(s)
- Graeme J. M. Cowan
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Alison M. Creasey
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Kelwalin Dhanasarnsombut
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Alan W. Thomas
- Biomedical Primate Research Center, Rijswijk, The Netherlands
| | | | - David R. Cavanagh
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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11
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Noranate N, Prugnolle F, Jouin H, Tall A, Marrama L, Sokhna C, Ekala MT, Guillotte M, Bischoff E, Bouchier C, Patarapotikul J, Ohashi J, Trape JF, Rogier C, Mercereau-Puijalon O. Population diversity and antibody selective pressure to Plasmodium falciparum MSP1 block2 locus in an African malaria-endemic setting. BMC Microbiol 2009; 9:219. [PMID: 19832989 PMCID: PMC2770483 DOI: 10.1186/1471-2180-9-219] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 10/15/2009] [Indexed: 11/17/2022] Open
Abstract
Background Genetic evidence for diversifying selection identified the Merozoite Surface Protein1 block2 (PfMSP1 block2) as a putative target of protective immunity against Plasmodium falciparum. The locus displays three family types and one recombinant type, each with multiple allelic forms differing by single nucleotide polymorphism as well as sequence, copy number and arrangement variation of three amino acid repeats. The family-specific antibody responses observed in endemic settings support immune selection operating at the family level. However, the factors contributing to the large intra-family allelic diversity remain unclear. To address this question, population allelic polymorphism and sequence variant-specific antibody responses were studied in a single Senegalese rural community where malaria transmission is intense and perennial. Results Family distribution showed no significant temporal fluctuation over the 10 y period surveyed. Sequencing of 358 PCR fragments identified 126 distinct alleles, including numerous novel alleles in each family and multiple novel alleles of recombinant types. The parasite population consisted in a large number of low frequency alleles, alongside one high-frequency and three intermediate frequency alleles. Population diversity tests supported positive selection at the family level, but showed no significant departure from neutrality when considering intra-family allelic sequence diversity and all families combined. Seroprevalence, analysed using biotinylated peptides displaying numerous sequence variants, was moderate and increased with age. Reactivity profiles were individual-specific, mapped to the family-specific flanking regions and to repeat sequences shared by numerous allelic forms within a family type. Seroreactivity to K1-, Mad20- and R033 families correlated with the relative family genotype distribution within the village. Antibody specificity remained unchanged with cumulated exposure to an increasingly large number of alleles. Conclusion The Pfmsp1 block2 locus presents a very large population sequence diversity. The lack of stable acquisition of novel antibody specificities despite exposure to novel allelic forms is reminiscent of clonal imprinting. The locus appears under antibody-mediated diversifying selection in a variable environment that maintains a balance between the various family types without selecting for sequence variant allelic forms. There is no evidence of positive selection for intra-family sequence diversity, consistent with the observed characteristics of the antibody response.
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Affiliation(s)
- Nitchakarn Noranate
- Institut Pasteur, Unité d'Immunologie Moléculaire des Parasites, CNRS URA 2581, 28 rue du Dr ROUX, 75724 Paris Cedex 15, France.
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12
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Daubenberger CA, Pluschke G, Zurbriggen R, Westerfeld N. Development of influenza virosome-based synthetic malaria vaccines. Expert Opin Drug Discov 2008; 3:415-23. [DOI: 10.1517/17460441.3.4.415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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13
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Dubey ML, Malla N, Mahajan RC. Plasmodium falciparum: Polymorphism in the MSP-1 gene in Indian isolates and predominance of certain alleles in cerebral malaria. Exp Parasitol 2006; 112:139-43. [PMID: 16300763 DOI: 10.1016/j.exppara.2005.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Revised: 10/07/2005] [Accepted: 10/08/2005] [Indexed: 11/22/2022]
Abstract
Polymorphism in the block-2 region of merozoite surface protein-1 gene in 69 North Indian Plasmodium falciparum isolates was studied by PCR and RFLP using Dra-1 endonuclease. On the basis of molecular weight of the PCR products, considerable size polymorphism in target gene was seen and 69 isolates were classified into five allelic types. On RFLP, the isolates in three allelic types were further divided into two sub-allelic types each and thus eight genetic types could be identified. Interestingly, all five allelic types were identified in 47 isolates from uncomplicated (non-cerebral) malaria patients while only two allelic types (Type 2 and 3) were seen amongst 22 isolates from cerebral malaria patients. Furthermore, on RFLP, one subtype (2A) was predominantly seen in cerebral malaria patients and one subtype (3A) was exclusively found in cerebral malaria patients. These observations suggest that a few, comparatively more virulent isolates prevalent in an area may cause severe disease (cerebral malaria) which can be identified by molecular techniques like PCR-RFLP.
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14
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Cavanagh DR, Dodoo D, Hviid L, Kurtzhals JAL, Theander TG, Akanmori BD, Polley S, Conway DJ, Koram K, McBride JS. Antibodies to the N-terminal block 2 of Plasmodium falciparum merozoite surface protein 1 are associated with protection against clinical malaria. Infect Immun 2004; 72:6492-502. [PMID: 15501780 PMCID: PMC522997 DOI: 10.1128/iai.72.11.6492-6502.2004] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This longitudinal prospective study shows that antibodies to the N-terminal block 2 region of the Plasmodium falciparum merozoite surface protein 1 (MSP-1) are associated with protection against clinical malaria in an area of stable but seasonal malaria transmission of Ghana. Antibodies to the block 2 region of MSP-1 were measured in a cohort of 280 children before the beginning of the major malaria transmission season. The cohort was then actively monitored for malaria, clinically and parasitologically, over a period of 17 months. Evidence is presented for an association between antibody responses to block 2 and a significantly reduced risk of subsequent clinical malaria. Furthermore, statistical survival analysis provides new information on the duration of the effect over time. The results support a conclusion that the block 2 region of MSP-1 is a target of protective immunity against P. falciparum and, thus, a promising new candidate for the development of a malaria vaccine.
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Affiliation(s)
- David R Cavanagh
- Institute of Cell, Animal and Population Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, West Mains Rd., EH9 3JT, Scotland, UK.
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15
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Sakihama N, Matsuo T, Mitamura T, Horii T, Kimura M, Kawabata M, Tanabe K. Relative frequencies of polymorphisms of variation in Block 2 repeats and 5' recombinant types of Plasmodium falciparum msp1 alleles. Parasitol Int 2004; 53:59-67. [PMID: 14984836 DOI: 10.1016/j.parint.2003.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Accepted: 11/12/2003] [Indexed: 11/25/2022]
Abstract
The mechanisms producing the genetic polymorphism at Plasmodium falciparum merozoite surface antigen-1 locus (pfmsp1) include the insertion and deletion of the different type of dimorphic Block 2 9-nucleotide repeat units as well as the intragenic recombination. To study relative occurrence frequencies of these two distinct mechanisms, we have developed a sensitive PCR strategy to identify both 5' recombinant types and the number of Block 2 repeats from the same sample. This method can specifically detect the target 5' recombinant type (Blocks 2-6) at the sensitivity of 1-4 copies of the pfmsp1. Applying the new method to field isolates from the Solomon Islands enabled us to identify six different 5' recombinant types and variation in Block 2 repeat number in three of them, thus distinguishing 10 different alleles. Distribution of these alleles in local three villages in the study area suggests that frequencies of variation in the number of Block 2 9-bp repeats and recombination events within Blocks 2-6 are mutually independent and the frequency of repeat variation is relatively high as compared to that of recombination events at the pfmsp1 locus in P. falciparum populations from the Solomon Islands.
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Affiliation(s)
- Naoko Sakihama
- Laboratory of Biology, Osaka Institute of Technology, 5-16-1, Ohmiya, Asahi-ku, Osaka 535-8585, Japan
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16
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Helg A, Mueller MS, Joss A, Pöltl-Frank F, Stuart F, Robinson JA, Pluschke G. Comparison of analytical methods for the evaluation of antibody responses against epitopes of polymorphic protein antigens. J Immunol Methods 2003; 276:19-31. [PMID: 12738356 DOI: 10.1016/s0022-1759(03)00075-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Surface exposed protein antigens of the malaria parasite Plasmodium falciparum frequently harbor multiple dimorphic amino acid positions. These are associated with parasite immune evasion and represent a major obstacle for subunit vaccine design. Here, we have analyzed the flexibility of the humoral immune response against a semiconserved sequence (YX(44)LFX(47)KEKMX(52)L) of the key malaria blood stage vaccine candidate merozoite surface protein-1 (MSP-1). Monoclonal antibodies (mAbs) raised against one of the six described natural sequence variants of MSP-1(43-53) were analyzed for cross-reactivity with the other allelic forms, which differ in one to three positions from the immunizing sequence. Enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) spectroscopy demonstrated marked differences in mAb binding avidity to the variant sequences and isothermal titration calorimetry (ITC) provided evidence for a very low affinity of some of the interactions. In immunofluorescence analysis (IFA) and Western blotting analysis, the mAbs nevertheless stained all analyzed parasite clones expressing MSP-1(43-53) variant sequences. When used for the evaluation of humoral immune responses in clinical malaria vaccine trials, these two commonly used methods may thus not be suitable to distinguish biologically functional high affinity antibody responses from irrelevant low-affinity cross-reactivities.
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Affiliation(s)
- A Helg
- Swiss Tropical Institute, Socinstrasse 57, CH 4002, Basel, Switzerland
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17
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Daubenberger CA, Diaz D, Curcic M, Mueller MS, Spielmann T, Certa U, Lipp J, Pluschke G. Identification and characterization of a conserved, stage-specific gene product of Plasmodium falciparum recognized by parasite growth inhibitory antibodies. Infect Immun 2003; 71:2173-81. [PMID: 12654839 PMCID: PMC152076 DOI: 10.1128/iai.71.4.2173-2181.2003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have identified a novel conserved protein of Plasmodium falciparum, designated D13, that is stage-specifically expressed in asexual blood stages of the parasite. The predicted open reading frame (ORF) D13 contains 863 amino acids with a calculated molecular mass of 99.7 kDa and displays a repeat region composed of pentapeptide motives. Northern blot analysis with lysates of synchronized blood stage parasites showed that D13 is highly expressed at the mRNA level during schizogony. The first N'-terminal 138 amino acids of D13 were expressed in Escherichia coli and the purified protein was used to generate anti-D13 monoclonal antibodies (MAbs). Using total lysates of blood stage parasites and Western blot analysis, these MAbs stained one single band of approximately 100 kDa, corresponding to the predicted molecular mass of ORF D13. Western blot analysis demonstrated further that D13 is expressed during schizogony, declines rapidly in early ring stages and is undetectable in trophozoites. D13 protein is localized in individual merozoites in a distinct area, as demonstrated by indirect immunofluorescence analysis. After subcellular fractionation, D13 was confined to the pelleted fraction of the parasite lysate and its extraction by alkaline carbonate buffer treatment indicated that D13 is not a membrane-integral protein. Inclusion of certain anti-D13 MAbs into in vitro cultures of blood stage parasites resulted in considerable reduction in parasite growth. The N'-terminal domain encompassing 158 amino acids is 94 and 95%, respectively, identical at the amino acid level between Plasmodium knowlesi, Plasmodium yoelii, and P. falciparum. In summary, we describe a novel stage-specifically expressed, highly conserved gene product of P. falciparum that is recognized by parasite growth inhibitory antibodies.
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Affiliation(s)
- Claudia A Daubenberger
- Molecular Immunology, Swiss Tropical Institute, Socinstrasse 57, 4002 Basel, Switzerland.
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18
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Daubenberger CA, Nickel B, Ciatto C, Grütter MG, Pöltl-Frank F, Rossi L, Siegler U, Robinson J, Kashala O, Patarroyo ME, Pluschke G. Amino acid dimorphism and parasite immune evasion: cellular immune responses to a promiscuous epitope of Plasmodium falciparum merozoite surface protein 1 displaying dimorphic amino acid polymorphism are highly constrained. Eur J Immunol 2002; 32:3667-77. [PMID: 12516559 DOI: 10.1002/1521-4141(200212)32:12<3667::aid-immu3667>3.0.co;2-c] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Like most other surface-exposed antigens of Plasmodium falciparum, the leading malaria vaccine candidate merozoite surface protein (MSP)-1 contains a large number of dimorphic amino acid positions. This type of diversity is presumed to be associated with parasite immune evasion and represents one major obstacle to malaria subunit vaccine development. To understand the precise role of antigen dimorphism in immune evasion, we have analyzed the flexibility of CD4 T cell immune responses against a semi-conserved sequence stretch of the N-terminal block of MSP-1. While this sequence contains overlapping promiscuous T cell epitopes and is a target for growth inhibitory antibodies, three dimorphic amino acid positions may limit its suitability as component of a multi-epitope malaria vaccine. We have analyzed the CD4 T cell responses in a group of human volunteers immunized with a synthetic malaria peptide vaccine containing a single MSP-143-53 sequence variant. All human T cell lines and HLA-DR- or -DP-restricted T cell clones studied were exclusively specific for the sequence variant used for immunization. Competition peptide binding assays with affinity-purified HLA-DR molecules indicated that dimorphism does not primarily affect HLA binding. Modeling studies of the dominant restricting HLA-DRB1*0801 molecule showed that the dimorphic amino acids represent potential TCR contact residues. Lack of productive triggering of the TCR by MHC/variant peptide ligand complexes thus seems to be the characteristic feature of parasite immune evasion associated with antigen dimorphism.
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19
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Sakihama N, Kaneko A, Hattori T, Tanabe K. Limited recombination events in merozoite surface protein-1 alleles of Plasmodium falciparum on islands. Gene 2001; 279:41-8. [PMID: 11722844 DOI: 10.1016/s0378-1119(01)00748-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Intragenic recombination is a principal mechanism for the generation of allelic variation in the merozoite surface protein-1 gene (Msp-1) of the human malaria parasite Plasmodium falciparum. In the present study, linkage disequilibrium between the 5'- and 3'-polymorphic sites was analyzed to determine the frequency of recombination events in Msp-1 in parasite populations on four islands in Vanuatu, the southwestern Pacific, where malaria transmission is moderate and comparable to other mesoendemic areas. Of 141 isolates, whose 5'-haplotypes (Msp-1 blocks 2-6) were determined by PCR-based typing, 138 were successfully sequenced for the 3'-polymorphism (block 17). A total of four distinct 5'-haplotypes and three distinct 3'-sequence types were identified with apparently different frequency distribution among islands. The number of 5'-haplotypes in each island was one to four, far smaller than in other previously studied geographic areas (ten to 21). Associations between the 5'- and 3'-polymorphisms (here termed Msp-1 gene types) were subjected to the R(2) linkage disequilibrium test. The test revealed complete or very strong linkage disequilibrium in all four islands. Mixed infection was unusually rare (2.1%) and the mean number of Msp-1 alleles per person was nearly 1.0. The heterozygosity of the Msp-1 gene type calculated for each island (h=0.41-0.65) was significantly lower than that in other areas of comparable endemicity (h=0.81-0.89) (P<0.01). These results indicate that recombination events in Msp-1 would be extremely limited in Vanuatu, and stress that the frequency of recombination in Msp-1 is determined by not only the intensity of malaria transmission but the frequency of mixed clone infections, the mean number of clones per person and a repertoire of clones in a local area.
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Affiliation(s)
- N Sakihama
- Laboratory of Biology, Osaka Institute of Technology, Ohmiya, Asahi-ku, 535-8585, Osaka, Japan
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20
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Daubenberger CA, Pöltl-Frank F, Jiang G, Lipp J, Certa U, Pluschke G. Identification and recombinant expression of glyceraldehyde-3-phosphate dehydrogenase of Plasmodium falciparum. Gene 2000; 246:255-64. [PMID: 10767547 DOI: 10.1016/s0378-1119(00)00069-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The gene coding for the cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) was isolated from Plasmodium falciparum. The gene contains 1 intron and the A+T content is characteristic for the codon usage of P. falciparum. The predicted open reading frame codes for 337 amino acids (36651Da) and is 63.5% identical to the human erythrocytic GAPDH. GAPDH sequences from several field isolates of P. falciparum displayed 100% conservation. Phylogenetic analysis supports the hypothesis that dinoflagellates and Plasmodium are closely related. The protein encoded by the pfGAPDH was expressed recombinantly in Escherichia coli and exhibited enzymatic activity with NAD(+) but not with NADP(+) as cofactor. Antiserum raised against the recombinantly expressed enzyme detected specifically all developmental stages of cultured P. falciparum blood-stage parasites.
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Affiliation(s)
- C A Daubenberger
- Swiss Tropical Institute, Molecular Immunology, Socinstrasse 57, 4002, Basel, Switzerland.
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