Gupte Gouri M, Ramdasi Ashwini Y, Kulkarni Anupriya S, Arankalle V A
National Institute of Virology, Pashan, Pune, India.
Indian J Gastroenterol. 2010 Jun;29(3):101-5. doi: 10.1007/s12664-010-0030-3. Epub 2010 Jul 25.
Hepatitis C virus (HCV), a major causative agent of chronic hepatitis, is classified into six major genotypes. Genotype 3 HCV infection is more sensitive to interferon therapy. In India, genotype 3, particularly subtype 3a, HCV infections are common. Three novel HCV subtypes i.e., 3g, 3j, and 3i were identified from India based on partial genomic sequences. This report provides full genome sequences of one isolate each of subtypes 3i and 3a.
Serum samples positive for subtype 3i and 3a HCV RNA based on core region genomic sequences were studied. Complete HCV genomes were amplified as 11 overlapping PCR fragments and sequenced.
The complete genomic sequence of Indian HCV 3i isolate clustered with other genotype 3 sequences, and was closer to subtypes 3b and 3a (80.5% and 79.1% [SD 0.4%] nucleotide identity). Nucleotide similarities were the highest in the core region (86.1-88.7%), and the least in the E2 region (69.4-70.7%). Phylogenetic tree analysis confirmed the existence of a separate subtype 3i. The Indian HCV 3a isolate's complete genomic sequences clustered with previously known genotype 3a sequences with a nucleotide similarity of 91.1% (SD 0.2%). Neither isolates showed evidence of recombination of different HCV genotypes.
The information on complete genomic sequences of the genotype 3 HCV isolates should be helpful in future studies on HCV evolution and classification, and for development of newer therapeutic and preventive strategies against this infection.
丙型肝炎病毒（HCV）是慢性肝炎的主要致病因子，可分为六种主要基因型。3型HCV感染对干扰素治疗更为敏感。在印度，3型HCV感染很常见，尤其是3a亚型。基于部分基因组序列，从印度鉴定出三种新型HCV亚型，即3g、3j和3i。本报告提供了3i和3a亚型各一个分离株的全基因组序列。
对基于核心区域基因组序列的3i和3a亚型HCV RNA阳性血清样本进行研究。将完整的HCV基因组扩增为11个重叠的PCR片段并进行测序。
印度HCV 3i分离株的完整基因组序列与其他3型序列聚类，且与3b和3a亚型更接近（核苷酸同一性分别为80.5%和79.1%[标准差0.4%]）。核苷酸相似性在核心区域最高（86.1 - 88.7%），在E2区域最低（69.4 - 70.7%）。系统发育树分析证实了单独的3i亚型的存在。印度HCV 3a分离株的完整基因组序列与先前已知的3a基因型序列聚类，核苷酸相似性为91.1%（标准差0.2%）。两种分离株均未显示出不同HCV基因型重组的证据。
3型HCV分离株完整基因组序列的信息应有助于未来关于HCV进化和分类的研究，以及开发针对这种感染的更新治疗和预防策略。
