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目的探讨HIV-1 B’亚型毒株感染者Nef蛋白细胞毒性淋巴细胞(cytotoxic T lymphocyte,CTL)表位变异及其与病毒载量的相关性。方法从137例HIV-1 B’亚型毒株感染者的血浆样本中提取病毒RNA,经逆转录及巢式PCR扩增获得Nef基因并测序,将获得的Nef基因序列翻译为蛋白序列,然后与HIV免疫学数据库中经过实验证实的CTL表位进行比对,分析Nef蛋白CTL表位变异与感染者病毒载量的关系。结果与HIV免疫学数据库中CTL表位的比较发现,本研究137例HIV-1 B’亚型毒株感染者病毒Nef蛋白大部分CTL表位相对保守,只有5个表位的变异频率超过10%,CTL表位旁序列的变异程度较锚着位点变异大,表位旁上下游第一位氨基酸的突变频率较高,表位氨基酸总变异频率、锚着位点和表位旁序列的氨基酸变异频率与病毒载量呈正相关,非锚着位点氨基酸的变异与病毒载量无相关性。结论 HIV-1 B’亚型毒株感染者Nef蛋白大部分CTL表位较保守,CTL表位旁序列变异程度较锚着位点大,表位旁上下游第一位氨基酸的突变频率较高,推测表位旁序列氨基酸的变异可能是Nef蛋白CTL逃逸突变的主要方式,Nef蛋白CTL表位变异与病毒适应性损伤的关系还需进一步研究。
Objective To investigate the variation of Nef protein cytotoxic T lymphocyte (CTL) epitopes and their relationship with viral load in HIV-1 B subtype infected patients. Methods The viral RNA was extracted from plasma samples from 137 HIV-1 B ’subtype infected individuals. The Nef gene was obtained by reverse transcription and nested PCR and sequenced. The obtained Nef gene sequence was then translated into protein sequence. Then, And the HIV immunology database has been experimentally confirmed CTL epitopes were compared Nef protein CTL epitope variation and the relationship between viral load. Results Compared with the CTL epitopes in the HIV immunology database, the majority of CTL epitopes in the virus Nef protein of 137 HIV-1 B ’subtypes were relatively conservative in this study, and only 5 epitopes mutated more than 10 %, The degree of variation of the sequences next to the CTL epitopes is larger than that of the anchor sites. The frequency of the first amino acid mutation upstream and downstream of the epitope is higher, and the frequency of total amino acid mutations, anchoring sites and para- The frequency of amino acid mutation was positively correlated with the viral load, but the amino acid variation at the non-anchor site was not related to the viral load. Conclusion Most of the CTL epitopes of Nef protein in patients with HIV-1 B ’subtype are more conservative than those in the adjacent CTL epitopes. The frequency of the first amino acid mutation upstream and downstream of the epitope is higher It is speculated that the variation of amino acid sequence beside the epitope may be the main way to escape the mutation of Nef protein CTL. The relationship between the Nef protein CTL epitope variation and virus adaptive damage needs further study.