慢性乙型肝炎患者HBV核心区与聚合酶区特异性CTL表位变异分析

摘要

Objective To compare mutation occurrence of hepatitis B virus (HBV)core(C)protein and polymerase (Pol)protein specific cytotoxic T lymphocytes (CTL)epitopes among patients with acute (AHB),chronic (CHB) and chronic severe hepatitis B(CSHB).Methods HLA-A2 and HLA-A11 typing were performed in 516 patients with hepatitis B.Nested PCB was used to amplify HBV C gene and Pol gene followed by sequencing of PCR products.HBV genotyping was determined based on the S gene sequences.The mutations of 9 HLA-A2-restricted C protein- and Pol protein-specific CTL epitopes,and one HLA-A11-restricted C protein-specific CTL epitope were analyzed by Vector NTI software,respectively.Results Two hundred forty-seven (47.86％)patients were identified as HLA-A2 positive,among whom 67 were with AHB, 109 with CHB and 71 with CSHB,while two hundred and twenty(42.64％)patients were identified as HLA-A11 positive,among whom 67 were with AHB, 107 with CHB and 46 with CSHB;The mutation differences of CTL HLA-A2-restrcted epitopes were as follows: (1)When all HLA-A2+ patients with AHB,CHB and CSHB were compared,no obvious significant difference of the mutation were observed; (2)When only HLA-A2+ infected with genotype B virus were compared, very significant difference (P＜0.01)of the mutation of P455-463 and P816-824 epitopes were observed among the three groups; (3) When only HLA-A2+ patients infected with genotype C virus were compared,no obvious significant difference were observed among the three groups; (4) There was only one HLA-A11-restricted C protein CTL epitope of C88-96 identified.When all HLA-A11+ patients were conpared, significant difference (P＜0.05)was obtained among the three groups for this epitope mutation.Conclusion Significant difference exists in the mutation of certain HBV-specific CTL epitopes of proteins C and P,which is influenced by HBV genotypes.The mutation is possibly associated with the pathogenesis of severity and chronicity of hepatitis B.%目的 比较急性乙型肝炎、慢性乙型肝炎与慢性重型乙型肝炎患者HBV C蛋白和 Pol蛋白特异性 CTL 表位变异的差异,以探讨乙型肝炎重症化和慢性化的可能机理.方法 对516例乙型肝炎患者的血清进行HLA-A2和A11分型;用巢式PCR扩增血清HBV C基因与Pol基因并对PCR产物进行序列测定;根据HBV S基因序列,用VirusBlast软件鉴定患者感染的HBV基因型;用Vector NTI软件对目前已知的HLA-A2限制性的4个C蛋白和5个Pol蛋白特异性CTL表位与HLA-A11限制性的1个C蛋白表位进行序列分析.结果 247例(47.86%)患者HLA-A2阳性,其中 AHB 67例,CHB 109例,CSHB 71例;220例(42.64%)患者HLA-A11阳性,其中 AHB 67例,CHB 107例,CSHB 46例;CTL表位变异分析结果如下:①在3组HLA-A2阳性患者,表位变异发生率无显著性差异(P>0.05);②在三组HLA-A2阳性HBV B基因型患者,P455-463和P816-824表位变异有极显著性差异(P<0.01);③在三组HLA-A2阳性HBV C基因型患者,各表位变异无显著性差异;④在三组HLA-A11阳性患者,C88-96表位变异发生率有显著性差异(P<0.05),三组HBV C基因型患者,表位变异发生率有极显著性差异(P<0.01),而在HBV B基因型患者,各表位变异无显著性差异(P>0.05).结论 某些HBV C蛋白和Pol蛋白特异性CTL表位在AHB、CHB和CSHB患者间变异有明显差异,并且受感染病毒基因型的影响.CTL表位变异可能与乙型肝炎的重症化和慢性化机制相关.