Cerny A, McHutchison J G, Pasquinelli C, Brown M E, Brothers M A, Grabscheid B, Fowler P, Houghton M, Chisari F V
Scripps Research Institute, La Jolla, California 92037.
J Clin Invest. 1995 Feb;95(2):521-30. doi: 10.1172/JCI117694.
The HLA class I-restricted cytotoxic T lymphocyte (CTL) response is a major defense mechanism in viral infections. It has been suggested that the CTL response may contribute to viral clearance and liver cell injury during hepatitis C virus (HCV) infection. To test this hypothesis requires an understanding of the characteristics of HCV-specific cytotoxic effector cells and identification of the target antigens to which they respond. To begin this process we stimulated peripheral blood mononuclear cells (PBMC) from a group of HLA-A2 positive patients with chronic hepatitis C with a panel of 130 HCV-derived peptides containing the HLA-A2 binding motif. Effector cells were tested for their capacity to lyse HLA-A2-matched target cells that were either sensitized with peptide or infected with a vaccinia virus construct containing HCV sequences. Using this approach we have identified nine immunogenic peptides in HCV, three of which are derived from the putative core protein, three from the nonstructural (NS) 3 domain, two from NS4 and one from NS5. Selected responses were shown to be HLA-A2 restricted, mediated by CD8+ T cells and to recognize endogenously synthesized viral antigen. Unexpectedly, peptide-specific CTL responses could also be induced in sero-negative individuals, suggesting in vitro activation of naive CTL precursors. The precursor frequency of peptide-specific CTL was 10 to 100-fold higher in infected patients compared to uninfected controls, and the responses were greatly diminished by removal of CD45 RO+ (memory) T cells. Further quantitative studies are clearly required to establish whether a correlation exists between the HCV-specific CTL response and the clinical course of this disease. Definition of the molecular targets of the human CTL response to HCV creates this opportunity, and may also contribute to the development of a T cell-based HCV vaccine.
HLA I类分子限制性细胞毒性T淋巴细胞（CTL）反应是病毒感染中的主要防御机制。有研究表明，CTL反应可能在丙型肝炎病毒（HCV）感染期间促进病毒清除及肝细胞损伤。要验证这一假说，需要了解HCV特异性细胞毒性效应细胞的特征，并鉴定它们所应答的靶抗原。为启动这一进程，我们用一组包含HLA - A2结合基序的130种HCV衍生肽刺激了一组慢性丙型肝炎HLA - A2阳性患者的外周血单核细胞（PBMC）。检测效应细胞裂解HLA - A2匹配靶细胞的能力，这些靶细胞要么用肽致敏，要么感染含有HCV序列的痘苗病毒构建体。通过这种方法，我们在HCV中鉴定出了9种免疫原性肽，其中3种来自假定的核心蛋白，3种来自非结构（NS）3结构域，2种来自NS4，1种来自NS5。所选反应显示为HLA - A2限制性，由CD8 + T细胞介导，并识别内源性合成的病毒抗原。出乎意料的是，在血清阴性个体中也能诱导出肽特异性CTL反应，这表明幼稚CTL前体在体外被激活。与未感染的对照组相比，感染患者中肽特异性CTL的前体频率高10至100倍，去除CD45 RO +（记忆）T细胞后反应大大减弱。显然需要进一步的定量研究来确定HCV特异性CTL反应与该疾病临床进程之间是否存在相关性。确定人类对HCV的CTL反应的分子靶点创造了这样的机会，也可能有助于基于T细胞的HCV疫苗的开发。
