恶性疟原虫海南、云南、安徽株裂殖子表面抗原MSA2基因的克隆和序列分析

Sequence analysis of genes encoding merozoite surface antigen-2 from three Chinese isolates of Plasmodium falciparum

应用ＰＣＲ技术扩增并克隆了恶性疟原虫海南、云南、安徽三个地理株的ＭＳＡ２基因，测定并分析了全基因序列。结果表明，海南、云南、安徽株ＭＳＡ２基因序列完全相同，全长为７９５ｂｐ，编码２６４个氨基酸，与ＦＣＱ－２７／ＰＮＧ株ＭＳＡ２高度同源。对抗原表位进行多参数综合分析表明，我国虫株除具有国外已确定的抗原表位ＳＴＮＳ、ＤＴＰＴＡＴＥ外，在第５３—７２位氢基酸间可能具有一个新的抗原表位。

The First Military Medical University State Key Laboratory of Genetic Engineering, Fudan University Genes encoding the merozoite surface antigen-2 of three Chinese isolates of P. falciparum FCC-1/HN ,PFD-3/YN and PFC-1/AH were cloned and sequenced.Comparison among MSA2 sequences of dif-ferent isolates of P.falciparum shows that there is no difference among the three Chinese isolates. MSA2genes of Chinese isolates belong to FC-27 allelic family.Compared with MSA2 sequence of FCQ-27,onlya few point mutations and a short stretch of frame-shift are detected.Possible antigenic epitopes on the de-duced amino acid sequence was also analyzed.The two well-defined FC-27 epitopes STNS and DTPTATEalsoexist in the Chinese isolates.The amino acid substitutions occurred between AA53 and AA72 dramati-cally increase the hydrophilic index and flexibility of the corresponding region, implying that there may bea novel antigenic epitope specific for Chinese isolates in this domain.