Background: An effective malaria vaccine is an urgently needed tool to fight against human malaria, the most deadly parasitic disease of humans. One promising candidate is the merozoite surface protein-3 (MSP-3) of Plasmodium falciparum. This antigenic protein, encoded by the merozoite surface protein (msp-3) gene, is polymorphic and classified according to size into the two allelic types of K1 and 3D7. A recent study revealed that both the K1 and 3D7 alleles co-circulated within P. falciparum populations in Thailand, but the extent of the sequence diversity and variation within each allelic type remains largely unknown.
Methods: The msp-3 gene was sequenced from 59 P. falciparum samples collected from five endemic areas (Mae Hong Son, Kanchanaburi, Ranong, Trat and Ubon Ratchathani) in Thailand and analysed for nucleotide sequence diversity, haplotype diversity and deduced amino acid sequence diversity. The gene was also subject to population genetic analysis (F ) and neutrality tests (Tajima's D, Fu and Li D* and Fu and Li' F* tests) to determine any signature of selection.
Results: The sequence analyses revealed eight unique DNA haplotypes and seven amino acid sequence variants, with a haplotype and nucleotide diversity of 0.828 and 0.049, respectively. Neutrality tests indicated that the polymorphism detected in the alanine heptad repeat region of MSP-3 was maintained by positive diversifying selection, suggesting its role as a potential target of protective immune responses and supporting its role as a vaccine candidate. Comparison of MSP-3 variants among parasite populations in Thailand, India and Nigeria also inferred a close genetic relationship between P. falciparum populations in Asia.
Conclusion: This study revealed the extent of the msp-3 gene diversity in P. falciparum in Thailand, providing the fundamental basis for the better design of future blood stage malaria vaccines against P. falciparum.
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http://dx.doi.org/10.1186/s12936-016-1566-1 | DOI Listing |
Front Parasitol
May 2024
Disease Control and Elimination (DCE), Medical Research Council The Gambia Unit at the London School of Hygiene and Tropical Medicine (LSHTM), Fajara, Gambia.
Further understanding of the molecular mediators of alternative RBC invasion phenotypes in endemic malaria parasites will support malaria blood-stage vaccine or drug development. This study investigated the prevalence of sialic acid (SA)-dependent and SA-independent RBC invasion pathways in endemic parasites from Cameroon and compared the schizont stage transcriptomes in these two groups to uncover the wider repertoire of transcriptional variation associated with the use of alternative RBC invasion pathway phenotypes. A two-color flow cytometry-based invasion-inhibition assay against RBCs treated with neuraminidase, trypsin, and chymotrypsin and deep RNA sequencing of schizont stages harvested in the first replication cycle in culture were employed in this investigation.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, Thailand.
SURFINs protein family expressed on surface of both infected red blood cell and merozoite surface making them as interesting vaccine candidate for erythrocytic stage of malaria infection. In this study, we analyze genetic variation of Pfsurf4.1 gene, copy number variation, and frequency of SURFIN4.
View Article and Find Full Text PDFSci Rep
January 2025
Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou (IRR), Fundação Oswaldo Cruz (FIOCRUZ), Minas Gerais, Brazil.
Rapid Diagnostic Tests (RDTs) have been an important diagnostic tool for detecting P. falciparum malaria in resource-limited settings. Most tests are designed to detect the Histidine-rich Protein 2 (HRP2).
View Article and Find Full Text PDFParasitol Int
December 2024
Division of International Infectious Diseases Control, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan. Electronic address:
Through studies of new antimalarial drugs, we identified 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) as a potential drug candidate. Here, we analyzed the antimalarial action of a transdermal formulation (td) of N-89, designed for easy use by children, using Plasmodium berghei-infected mice as a model for malaria patients.
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