CRF01_AE CRF07_BC和B’亚型HIV-1 pol基因及耐药特征分析

Genotypic analysis of the pol gene and drug resistance of HIV-1 CRF01-AE,CRF07-BC and subtype B'isolates

目的研究中国部分地区新发现未经抗病毒治疗的艾滋病病毒Ⅰ型(HIV-1)感染者的耐药情况,及不同亚型毒株pol基因的多态性对耐药突变产生的影响。方法选取2005-2006年湖南、云南、四川和新疆4省(自治区,下同)当年确认的部分样本,进行核酸扩增及测序,利用系统进化及重组分析的方法确定亚型;根据美国斯坦福大学HIV-1耐药数据库,分析不同亚型毒株蛋白酶基因和逆转录酶基因的多态性和耐药突变情况;利用荷兰乌得勒支大学Vijver等人使用的一种遗传障碍定量方法,计算并比较不同亚型间耐药突变产生的遗传障碍。结果共得到84份样本PR基因区(1-99氨基酸)和RT基因区(1-272氨基酸)的序列,亚型分析显示:84份样本中B’亚型13份,01-AE重组亚型27份,07-BC重组亚型44份,其中18份样本在蛋白酶基因区的第10位和第71位存在次要耐药突变;来自云南省和湖南省的3份样本中,存在逆转录酶抑制剂相关耐药突变,分别是A62V、V179D和G190A。三种亚型在逆转录酶基因区的2个非核苷类抑制剂相关耐药突变位点V106M和V108I的遗传障碍存在差异,有显著的统计学意义(P<0.001)。结论4个地区未冶疗感染者中耐药发生的水平较低。遗传障碍的比较,CRF01-AE、CRF07-BC与B’亚型病人经治疗后主要耐药突变的发展模式应基本一致。

Objective To determine the prevalence of HIV drug resistance among recently infected drug-naive individuals in several provinces of China,and to analyze the impact of genetic polymorphism of different HIV-1 subtypes on antiretroviral susceptibility and evolution of drug resistant mutations. Methods HIV-1 PR and RT genes from untreated patients who were confirmed in 2005 -2006 from Hunan, Yunnan, Sichuan and Xinjiang in China were analyzed. The subtype was determined by phylogenetic and bootscanning analyses. The polymorphism and drug resistance were analyzed based on Stanford HIV Drug Resistance Database in US. The genetic barrier of specific drug resistant mutations was calculated and compared between CRF01 _ AE, CRF07 _ BC and subtype B＇strains using a method previously described by Vijver and his coworkers from University Medical Center in Utreche, the Netherlands. Results Of the total 84 patients, 13 were infected with subtype B＇, 27 were infected with CRF01 _ AE, and 44 were infected with CRF07 _ BC. NRTI and NNRTI resistant mutations were found from 3 patients in Yunnan and Hunan provinces. CRF07 _ BC strains had a decreased genetic barrier for the V106M mutation, as compared with subtype B ＇ and CRF01 _ AE isolates （P 〈 0. 001）. However,subtype B＇isolates had a higher genetic barrier for the V108I mutation than those of CRF01 _ AE and CRF07 _ BC strains （P 〈 0.001 ）. Conclusions The prevalence of HIV-1 drug resistance was at a low level among untreated patients in the four regions.With the exception of few mutations, the development of most major drug resistant mutations has a similar possibility in the three HIV-1 subtypes.