乙型肝炎患者HBV前S/S抗原特异性变异表位亲和力分析  

Affinity analysis of variant forms of HBV preS/S antigen-specific CTL epitopes in patients with hepatitis B infection

作　　者：孙志强[1] 许智慧[2] 任晓强[2] 刘妍[2] 王耀[2] 李晓东[2] 毛远丽[1] 徐东平[2] 

机构地区：[1]解放军302医院临床检验中心,北京100039 [2]解放军302医院传染病研究所病毒性肝炎研究室,北京100039

出　　处：《解放军医学杂志》2010年第12期1459-1461,共3页Medical Journal of Chinese People's Liberation Army

基　　金：国家重点基础研究发展计划课题(2007CB512803);国家“十一五”传染病重大专项子课题(2008ZX10002-005-6,2008ZX10002-011);北京市自然科学基金重点课题(7091006)

摘　　要：目的比较慢性乙型肝炎(CHB)和慢性重型肝炎(CSHB)患者HBV前S/S蛋白特异性细胞毒T淋巴细胞(CTL)表位变异发生率差异和亲和力变化,探讨HBV感染的发病机制。方法对2007年8月-2008年12月解放军302医院收治的385例乙型肝炎患者(CHB109例,CSHB71例)样本进行型特异性PCRHLA-A2分型;对HBV前S/S基因进行PCR产物直接测序,分析13个HLA-A2限制性前S/S蛋白中的特异性CTL表位序列,并用分子进化树进行HBV基因分型;通过BIMAS程序预测和T2细胞结合实验分析表位变异对CTL亲和力的影响。结果 HLA-A2阳性患者180例(46.8%);HBVC基因型感染138例,其中CHB患者86例、CSHB患者52例。CHB和CSHB患者的S177-185、S204-212、S131-139、S183-191表位变异发生率有显著差异(P<0.01或P<0.05)。BIMAS分析显示S204-212、S131-139和S183-191的表位变异形式对CTL结合的亲和力与未变异表位形式相比明显降低。T2细胞结合实验证实S131-139变异表位的亲和力较未变异表位降低了1.83倍。结论某些HBV前S/S抗原特异性CTL表位的变异发生率在同为C基因型感染的CHB和CSHB患者间有明显差异;表位变异可引起对CTL的亲和力改变从而影响机体对HBV感染的免疫应答。Objective To compare the changes in variation prevalence and affinity of HBV preS/S antigen-specific CTL epitopes between patients with chronic hepatitis B（CHB）and chronic severe hepatitis B（CSHB）,and to explore the pathogenesis of HBV infection.Methods HLA-A2typing was performed using type-specific PCR for 385HBV infected patients in 302Hospital from Aug.2007to Dec.2008.HBV preS/S genes were analyzed by direct PCR sequencing.The variation frequencies of 13HLA-A2-restricted preS/S protein-derived epitopes were analyzed.HBV genotypes were classified based on phylogenetic analysis of the S gene sequence.BIMAS program and T2 binding assay were employed to assess the influence of variation on the epitope affinity.Results One hundred and eighty（46.8%）patients were identified as HLA-A2positive.One hundred and thirty-eight patients including 86CHB patients and 52CSHB patients,were infected with genotype C HBV.Significant differences in the incidence of variant epitope were found between CHB and CHSB patients at epitope S177-185 （P〈0.01）,S204-212（P〈0.01）,S131-139（P〈0.05）and S183-191（P〈0.05）.BIMAS analysis showed that the variant epitopes of S204-212,S131-139and S183-191had a considerably decreased affinity in CTL binding compared to wild-type counterparts.T2binding assay verified that variant S131-139had a 1.83-fold decrease in affinity compared to wild-type S131-139.Conclusions There are significant differences between CHB and CSHB patients（both infected with genotype C HBV）in the incidence of some variant epitopes in preS/S protein.Variant epitopes may obviously alter its affinity to CTL binding and therefore possibly affect immune responses to HBV infection.

关 键 词：肝炎病毒 乙型 T淋巴细胞 细胞毒性 表位 T淋巴细胞 

分 类 号：R512.62[医药卫生—内科学]