HLA-E限制性多功能CD8+T细胞应答在汉滩病毒感染中的免疫保护及调节作用机制研究

Hemorrhagic fever with renal syndrome (HFRS) induced by Hantaan virus (HTNV) is a serious acute infectious disease distributed globally with great harm. As we known, the HLA-E restricted CD8+T cell response play an important role in many virus infectious diseases through the protection and regulation effects. Moreover, the HLA-E allele, which is common in the population, could be considered as the preferred molecule to be used in the design of the more specific and more effective peptide vaccine. However, so far, the effects and mechanisms of HTNV specific HLA-E restricted CD8+T cell response are still unknown. In our previous work, we have predicted and screened for a group of HLA-E high affinity HTNV 9-mer peptides. In this project, HLA-E restricted HTNV CD8+T cell epitopes will be identified systematically and the crystal structure of HLA-E/epitope complex will be resolved; the frequency of the HLA-E restricted HTNV specific CD8+T cell response in the peripheral blood of HFRS patients will be detected, and the correlation between the responses and the disease severity will be analyzed; the regulating effects of HLA-E restricted HTNV CD8+T cell response to the HTNV specific T cell line will be studied, which will reveal the possible mechanisms of immunoprotection and immunoregulation effects of HLA-E restricted HTNV CD8+T cell response during HFRS. The study may provide the important theoretical basis for finally overcome HTNV infection in clinical, and also for the design of the novel peptides vaccine for HTNV.

汉滩病毒（HTNV）感染引起的肾综合征出血热（HFRS）是全球广泛分布且危害极大的一种急性传染病。已知HLA-E限制性CD8+T细胞应答在多种病毒感染中发挥着免疫保护和调节作用，并且HLA-E等位基因在人群中普遍存在，是设计更为特异有效多肽疫苗的首选分子，但目前HTNV特异的HLA-E限制性CD8+T细胞应答研究尚是空白。我们前期预测并筛选出一组HLA-E高亲和力HTNV 结构蛋白9肽。本课题拟在此基础上系统鉴定HLA-E限制性HTNV CD8+T细胞表位并解析HLA-E/表位复合物晶体结构，分析HLA-E限制性HTNV CD8+T细胞发挥免疫保护作用的应答规律，明确HLA-E限制性CD8+T细胞系对效应T细胞的调节作用，揭示HFRS发病过程中HLA-E限制性CD8+T细胞应答发挥免疫保护和调节作用的机制和途径，为临床最终战胜HTNV感染及设计HTNV新型疫苗提供重要的理论依据。

汉滩病毒（HTNV）感染在人类可引起严重的肾综合征出血热疾病。已知HLA-E限制性CD8+T细胞在多种病毒感染中发挥着重要的免疫保护和调节作用，然而其在HTNV 感染中的作用研究尚未见报道。由于HLA-E是在人群中普遍存在的HLA等位基因位点，因此研究HLA-E限制性HTNV CD8+T细胞表位及其特异性应答的效应机制至关重要。在前期预测筛选HLA-E高亲和力HTNV 结构蛋白9肽基础上，鉴定HLA-E限制的HTNV CD8+T细胞表位，对HLA-E/表位复合物晶体结构进行初步解析，对表位特异性CD8+T细胞在患者外周血中的应答规律、表型及功能效应及机制进行了探讨。鉴定出6个HLA-E限制性HTNV CD8+T细胞9肽表位，发现其均可在患者外周血中诱导CD8+T细胞应答，且表位特异性CD8+T细胞频率及分泌IFN-γ水平在轻型/中型患者中高于重型/危重型患者，急性期应答频率高于恢复期。HLA-E限制表位特异性CD8+T细胞表现为HLA-DRhiCD38hiTCRαβhiNKG2DhiNKG2Alo表型的患者病情较轻，CD8+T细胞活化型受体表达水平及活化程度较NK细胞更高，且主要呈现TN 和TEMRA早/中期分化效应表型。表位特异性CD8+T细胞分泌IFN-γ、IL-2和颗粒酶B频率在轻/中型患者中高于重型/危重型，颗粒酶B水平与血浆病毒载量负相关。表位特异性CD8+T细胞在轻/中型患者中增殖能力更强，可有效杀伤靶细胞且急性期杀伤能力更强。表位特异性CD8+T细胞表达抑制性受体水平在重型/危重型患者中较高。四聚体双染检测发现HLA-A02与HLA-E01可能共同呈递HTNV表位。HLA-E/表位复合物有明显晶体生长但尚需优化条件。研究结果可为深入阐明HTNV感染中HLA-E限制性CD8+T细胞应答的免疫保护及调节作用机制提供基础，也可为设计新型HTNV疫苗提供明确有价值的实验资料。