Chaturong PutaporntipSomchai JongwutiwesMarcelo U. FerreiraHiroji KanbaraRachanee UdomsangpetchLiwang CuiChulalongkorn UniversityUniversidade de Sao Paulo - USPNagasaki UniversityMahidol UniversityPennsylvania State University2018-09-132018-09-132009-09-01Infection, Genetics and Evolution. Vol.9, No.5 (2009), 821-826156713482-s2.0-67749132432https://repository.li.mahidol.ac.th/handle/20.500.14594/26985Merozoite surface proteins (MSPs) of the malaria parasites are major candidates for vaccine development targeting asexual blood stages. However, the diverse antigenic repertoire of these antigens that induce strain-specific protective immunity in human is a major challenge for vaccine design and often determines the efficacy of a vaccine. Here we further assessed the genetic diversity of Plasmodium vivax MSP4 (PvMSP4) protein using 195 parasite samples collected mostly from Thailand, Indonesia and Brazil. Overall, PvMSP4 is highly conserved with only eight amino acid substitutions. The majority of the haplotype diversity was restricted to the two short tetrapeptide repeat arrays in exon 1 and 2, respectively. Selection and neutrality tests indicated that exon 1 and the entire coding region of PvMSP4 were under purifying selection. Despite the limited nucleotide polymorphism of PvMSP4, significant genetic differentiation among the three major parasite populations was detected. Moreover, microgeographical heterogeneity was also evident in the parasite populations from different endemic areas of Thailand. © 2009 Elsevier B.V. All rights reserved.Mahidol UniversityAgricultural and Biological SciencesBiochemistry, Genetics and Molecular BiologyImmunology and MicrobiologyMedicineArticleSCOPUS10.1016/j.meegid.2009.04.017