Jameel S, Zafrullah M, Ahmad M, Kapoor G S, Sehgal S
International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.
AIDS. 1995 Jul;9(7):685-90. doi: 10.1097/00002030-199507000-00003.
To determine the extent of HIV-1 genetic variation in Indian patients.
To avoid any bias in selecting viral variants, HIV-1 DNA was amplified directly from the peripheral blood mononuclear cells of patients and sequenced. Genetic similarity between Indian sequences and other geographic isolates was analysed by phylogenetic analysis algorithms.
A fragment encompassing the C2/V3-V5 regions of HIV-1 gp120 was amplified from the lymphocyte DNA of 12 Indian patients. Multiple clones from each patient were sequenced. Nucleotide sequences encompassing about 650 base pairs were aligned for the Indian and other geographically distinct isolates. Inter-isolate relationships were analysed by means of distance, parsimony and neighbour-joining algorithms.
Nucleotide sequence comparisons showed low interpatient variation. Amino-acid comparisons revealed a high degree of homology between Indian sequences in this study and those studied earlier. On distance and parsimony trees, most of the Indian sequences clustered together as subtype C. However, sequences from three patients also showed significant homologies and phylogenetic clustering outside of subtype C.
The predominant strain of HIV-1 in India belongs to subtype C and little interpatient nucleotide sequence divergence in the majority of cases suggests recent spread of HIV-1 in this region. This study also presents the first evidence for non-C subtypes in the Indian population with two epidemiologically linked samples remaining unclassified for any existing env subtype. The presence of variant subtypes in Indian patients sheds light on the transmission routes of HIV-1 to India and emphasizes the need to include these sequences in vaccine development strategies.
确定印度患者中HIV-1基因变异的程度。
为避免在选择病毒变异体时出现任何偏差，直接从患者外周血单个核细胞中扩增HIV-1 DNA并进行测序。通过系统发育分析算法分析印度序列与其他地理分离株之间的遗传相似性。
从12名印度患者的淋巴细胞DNA中扩增包含HIV-1 gp120的C2/V3-V5区域的片段。对每个患者的多个克隆进行测序。对印度和其他地理上不同的分离株中约650个碱基对的核苷酸序列进行比对。通过距离、简约和邻接法算法分析分离株间的关系。
核苷酸序列比较显示患者间变异较低。氨基酸比较显示本研究中的印度序列与早期研究的序列高度同源。在距离树和简约树上，大多数印度序列聚类为C亚型。然而，三名患者的序列在C亚型之外也显示出显著的同源性和系统发育聚类。
印度HIV-1的主要毒株属于C亚型，大多数病例中患者间核苷酸序列差异较小表明HIV-1近期在该地区传播。本研究还首次提供了印度人群中非C亚型的证据，两个有流行病学关联的样本未被归类为任何现有的env亚型。印度患者中变异亚型的存在揭示了HIV-1传入印度的传播途径，并强调了在疫苗开发策略中纳入这些序列的必要性。
