HLA—B宽特异性抗原表位Bw4对HCV特异性T细胞反应影响分析

Analysis of influence of HLA-B broad specific Bw4 motif on HCV specific T cell response

目的探讨HLA-B分子宽特异性抗原表位Bw4对丙型肝炎病毒（HCV）特异性T细胞反应的影响。方法以有偿献血途径感染HCV患者86例为研究对象，采用聚合酶链反应-序列特异性引物（PCR．SSP）方法，进行HLA分型。采用ELISPOT技术观察HCV非结构蛋白NS3、NS4及NS5诱导T细胞分泌IFN-γ反应。结果86例HCV感染者中Bw4／4纯合子患者29例（33．7％）、Bw4／6杂合子患者38例（44．2％）、Bw6／6纯合子患者19例（22．1％）。Bw4／4纯合子、Bw4／6杂合子、Bw6／6纯合子HCV病毒载量分别为（3．98±0．32）Log（IU／m1）、（5．22±0．29）Log（IU／m1）、（5．04±0．38）Log（IU／m1），3组比较，HCV病毒载量差异具有统计学意义（P=0．0153）。24例患者进行HCV非结构蛋白（NS3、NS4、NS5）诱导T细胞分泌IFN-γ反应，Bw4／4纯合子组HCV特异性T细胞反应率为50％（5／10），反应强度中位数为70SFU／10。PBMC（0—2020SFU／10。PBMC），非Bw4／4纯合子组中，HCV特异性T细胞反应率为14．28％（2／14），反应强度中位数为0SFU／10。PBMC（0—200SFU／10。PBMC）。两组比较，Bw4／4纯合子组反应强度明显高于非Bw4／4纯合子组，差异有统计学意义（P=0．0450），前者HCV特异性T细胞反应频率高于后者，差异接近有统计学意义（P=0．069）。在Bw4／4纯合子组，HCV以NS5诱导的T细胞反应为主体，其反应频率为50％（5／10），非Bw4／4纯合子组，NS5反应频率仅为7．14％（2／14），两者比较差异接近具有统计学意义（P=0．050）。结论携带Bw4／4纯合子HCV感染者，病毒载量较低，HCV特异性T细胞反应较强。Bw4可能通过增强HCV特异性T细胞免疫，进而产生对抗HCV复制的作用。

Objective To study the influence of Bw4 broad specific motif on hepatitis C virus （HCV） specific T cell response. Methods The 86 patients with HCV infection were enrolled in this study, who had history of non-standard paid blood donation. The sequence specific primer SSP-PCR and specific primer Amplification Refractory Mutation system was used to analyze HLA type. The T cell response, using PBMCs stimulated by HCV nonstructural protein NS3, NS4 and NS5 was tested by ELISPOT assay. Results There were 29 （33.7%） cases with homozygosity Bw4/4, 38 cases（44.2% ） with heterozygosity Bw4/6 and 19（22.1% ） cases with homozygosity Bw6/6 in 86 patients with HCV infection. HCV viral loads in Bw4/4 group, Bw4/6 group and Bw6/6 group were （3.98±0.32） Log（ copy/ml）, （5.22±0.29） Log（ copy/ml）, （5.04±0.38） Log（ copy/ml）, respectively and there was a significant difference in HCV load among three groups（P= 0.0153）. The 24 cases with HCV infection were test HCV specific T cell response divided homozygosity Bw4/4 group and non-homozygosity Bw4/4 group. The HCV specific T cell response frequeney in homozygosity Bw4/4 group and non-homozygosity Bw4/4 group was 50% （5/10） and 14.28% （2/14, respectively. The HCV specific T cell response magnitude in homozygosity Bw4/4 group and non-homozygosity Bw4/4 group was 70 SFU/106 PBMC （0-2020 SFU/106 PBMC ） and 0 SFU/106 PBMC （0-200 SFU/106 PBMC）. The response magnitude and frequency in homozygosity Bw4/4 group was significantly higher than that of non-homozygosity Bw4/4 group, P value was 0. 0450 and 0. 069, respectively. In homozygosity Bw4/4 group NS5 induced T cell response was dominant. The NS5 specific T cell response frequency in Bw4/4 group and non-Bw4/4 group was 50% and 7.14%, respectively, and the difference was nearly significant（P=0.050）. Conclusion The HCV-infected blood donors with homozygosity for HLA-Bw4 alleles is associated with a significant lower HCV virus load and stronger HCV specific T cell response, compared with non-homozygosity Bw4/4 group.