title: Limited global diversity of the Plasmodium vivax merozoite surface protein 4 gene.
abstract: Merozoite 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.
authors.affiliation: Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Chaturong
authors.initials: C
authors.lastname: Putaporntip
authors.forename: Somchai
authors.initials: S
authors.lastname: Jongwutiwes
authors.forename: Marcelo U
authors.initials: MU
authors.lastname: Ferreira
authors.forename: Hiroji
authors.initials: H
authors.lastname: Kanbara
authors.forename: Rachanee
authors.initials: R
authors.lastname: Udomsangpetch
authors.forename: Liwang
authors.initials: L
authors.lastname: Cui
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics*; D006801:Humans; D015810:Linkage Disequilibrium; D016780:Malaria, Vivax / Q000469:parasitology*; D010966:Plasmodium vivax / Q000235:genetics*; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics*; D012641:Selection, Genetic; D016415:Sequence Alignment
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C118839:merozoite surface protein 4, Plasmodium