Genetic polymorphism and natural selection in the C-terminal 42 kDa region of merozoite surface protein-1 among Plasmodium vivax Korean isolates.
BACKGROUND
The carboxy-terminal 42 kDa region of Plasmodium vivax merozoite surface protein-1 (PvMSP-1₄₂) is a leading candidate antigen for blood stage vaccine development. However, this region has been observed to be highly polymorphic among filed isolates of P. vivax. Therefore it is important to analyse the existing diversity of this antigen in the field isolates of P. vivax. In this study, the genetic diversity and natural selection in PvMSP-1₄₂ among P. vivax Korean isolates were analysed.


METHODS
A total of 149 P. vivax-infected blood samples collected from patients in Korea were used. The region flanking PvMSP-1₄₂ was amplified by PCR, cloned into Escherichia coli, and then sequenced. The polymorphic characteristic and natural selection of PvMSP-1₄₂ were analysed using the DNASTAR, MEGA4 and DnaSP programs.


RESULTS
A total of 11 distinct haplotypes of PvMSP-1₄₂ with 40 amino acid changes, as compared to the reference Sal I sequence, were identified in the Korean P. vivax isolates. Most of the mutations were concentrated in the 33 kDa fragment (PvMSP-1₃₃), but a novel mutation was found in the 19 kDa fragment (PvMSP-1₁₉). PvMSP-1₄₂ of Korean isolates appeared to be under balancing selection. Recombination may also play a role in the resulting genetic diversity of PvMSP-1₄₂.


CONCLUSIONS
PvMSP-1₄₂ of Korean P. vivax isolates displayed allelic polymorphisms caused by mutation, recombination and balancing selection. These results will be useful for understanding the nature of the P. vivax population in Korea and for development of a PvMSP-1₄₂ based vaccine against P. vivax.
Department of Parasitology and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660-751, Korea.
Jung-Mi
JM
Kang
Hye-Lim
HL
Ju
Yoo-Mi
YM
Kang
Dong-Hyun
DH
Lee
Sung-Ung
SU
Moon
Woon-Mok
WM
Sohn
Jae-Won
JW
Park
Tong-Soo
TS
Kim
Byoung-Kuk
BK
Na
D000595:Amino Acid Sequence; D001769:Blood / Q000469:parasitology; D003001:Cloning, Molecular; D016000:Cluster Analysis; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D006801:Humans; D007723:Korea; D016780:Malaria, Vivax / Q000469:parasitology; D020066:Merozoite Surface Protein 1 / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D010966:Plasmodium vivax / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011995:Recombination, Genetic; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
D016054:DNA, Protozoan; D020066:Merozoite Surface Protein 1