[Genotype detection of the merozoite surface protein alleles of Plasmodium vivax].

Objective: To develop a method for detecting the genotype of Plasmodium vivax merozoite surface protein 1 (PvMSP-1) alleles.

Methods: According to the sequence characteristic of PvMSP-1, nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to amplify the polymorphic region of ICB5-ICB6 which contains Q repeats and PvuII restriction site (Sal-1 type). The PCR product was digested by PvuII restriction endonuclease and the digested fragments were observed by 2% agarose gel electrophoresis. The allelic type was determined according to the banding pattern.

Results: Bands in size of 400 bp (Belem type) and/or 470 bp (Sal-1 type) appeared in all 98 P. vivax isolates, no band was found in negative control. After PvuII digestion, two Sal-1 type fragments (120 bp and 350 bp) were obtained from 45 samples of 470 bp. Single-band of 400 bp appeared in 3 of 40 samples with 400 bp as Belem type, two bands of 120 bp and 280 bp appeared from other 35 samples as recombination type III, and another 2 bands with 120 bp and 240 bp as Korean isolate.

Conclusion: The result showed that the nested PCR-RFLP may be applied in the detection and identification of the three PvMSP-1 allelic types in China.