我国云南、海南恶性疟原虫顶端膜抗原1基因结构域Ⅲ多态性分析

Sequence polymorphism of domain Ⅲ of the apical membrane antigen 1 of Plasmodium falciparum isolates from Yunnan Province and Hainan Province in China

目的 分析中国云南、海南两省恶性疟原虫顶端膜抗原1（apical membrane antigen 1,AMA-1）（Ⅲ）多态性.方法 收集海南、云南感染恶性疟原虫患者的血液187份,提取血样基因组DNA.设计两对引物扩增AMA-1（Ⅲ）基因,将PCR产物进行测序,分析其单倍型多样性.结果 187份样品中的AMA-1（Ⅲ）基因有23种单倍型,云南株有21种,海南株7种,海南有2种单倍型未在云南株中发现,云南株单倍型多样性高于海南株.AMA-1（Ⅲ）基因有9个多态位点,云南株有3份样品451位氨基酸残基的同义突变,云南、海南这些位点每种突变出现的比例不同.结论 恶性疟原虫AMA-1（Ⅲ）基因多态性在云南、海南两省各有其特点,对此结构域的群体遗传多样性分析可为针对此区域疟疾疫苗的设计提供有价值的信息.

Objective To analyze sequence polymorphism of the gene encoding the domain Ⅲ of Plasmodium falciparum apical membrane antigen 1 （AMA-1）. Methods Genomic DNA of the parasite was extracted from a total of 187 blood samples from individuals infected with P. falciparum. A two-step PCR strategy was applied to amplify the target gene using two pairs of net primers. Then the PCR product was sequenced and analyzed. Results The 187 PfAMA-1 （Ⅲ） sequences were grouped into a total of 23 kinds of haplotypes, in which 21 were found in Yunnan, and 7 in Hainan. Haplotype diversity in Yunnan was found to be higher than that in Hainan, however, two kinds of haplotypes from Hainan were not found in Yunnan. Nine polymorphic sites were found in the PfAMA-1 （Ⅲ）gene. Synonymous mutations at 451 condon were found in 3 isolates from Yunnan Province, and the ratios of these condon mutations distributed in the 9 positions were different between Yunnan and Hainan isolates. Conclusion Sequence polymorphisms in PfAMA-1 （Ⅲ） gene have their own characteristics in Yunnan and Hainan isolates. Genetic polymorphism studies of PfAMA-1 （Ⅲ） gene will provide useful data in designing PfAMA-1 （Ⅲ） -based vaccines against malaria.