HLA class I-restricted cytotoxic T lymphocytes specific for hepatitis C virus. Identification of multiple epitopes and characterization of patterns of cytokine release.

Abstract

Cytotoxic T lymphocytes (CTL) are important to the control of viral replication and their presence may be important to disease outcome. An understanding of the spectrum of proteins recognized by hepatitis C virus (HCV)-specific CTL and the functional properties of these cells is an important step in understanding the disease process and the mechanisms of persistent infection, which occurs in the majority of HCV-infected individuals. In this report we identify HCV-specific CTL responses restricted by the HLA class I molecules A2, A3, All, A23, B7, B8, and B53. The epitopes recognized by these intrahepatic CTL conform to published motifs for binding to HLA class I molecules, although in some cases we have identified CTL epitopes for which no published motif exists. The use of vectors expressing two different strains of HCV, HCV-1 and HCV-H, revealed both strain-specific and cross-reactive CTL. These HCV-specific CTL were shown to produce cytokines including IFN-y, TNF-a, GM-CSF, IL-8, and IL-10 in an antigen-and HLA class I-specific manner. These studies indicate that the CTL response to HCV is broadly directed and that as many as five different epitopes may be targeted in a single individual. The identification of minimal epitopes may facilitate peptide-specific immunization strategies. In addition, the release of proinflammatory cytokines by these cells may contribute to the pathogenesis of HCV-induced liver damage. (J. Clin. Invest. 1995. 96:2311-2321

Associations among clinical, immunological, and viral quasispecies measurements in advanced chronic hepatitis C

“…[21][22][23] Briefly, liver biopsy fragments were incubated in culture medium in the presence of 1 g/mL anti-CD3 and 100 U/mL recombinant human IL-2. When there was significant growth of lymphocytes extending out from the tissue (generally 2-4 weeks), the cells were restimulated at a density of approximately 2.5 ϫ 10 6 cells/mL with anti-CD3 and recombinant human IL-2 in the presence of allogeneic ␥-irradiated PBMCs.…”

“…Percent specific target cell lysis was calculated as described. [21][22][23] NA Assays. Pseudotype vesicular stomatitis virus (VSV) virions were prepared by phenotypic mixing of HCV chimeric envelope glycoproteins (E1-G or E2-G) and incorporation into the VSVts045 temperature-sensitive mutant as described.…”

Outcome of acute hepatitis C is related to virus-specific CD4 function and maturation of antiviral memory CD8 responses

“…[5][6][7][8][9][10][11] Alternatively, a small number of preselected epitopes of known HLA restriction or whole recombinant HCV proteins were tested. [12][13][14][15][16][17][18] Moreover, only limited information is available about the ex vivo profile of cytokine production in the acute phase of infection, because ELISPOT and intracellular cytokine staining (ICS) analysis were based on the measure of interferon-␥ (IFN-␥) only. 12,19 In the present study, we used panels of genotypematched, overlapping peptides covering the entire HCV sequence to obtain a reliable representation of the overall T cell response to HCV, associated with control of infec-tion or virus persistence.…”

An analysis of tumor necrosis factor α gene polymorphisms and haplotypes with natural clearance of hepatitis C virus infection

“…8 TNF-a is important for a number of Tcell-dependent immune processes including polarization to a Th1 response, induction of apoptosis, and regulation of proliferation. TNF-a has been implicated as an important cytokine in HCV infection since CTLs in the liver secrete TNF-a, 9 elevated serum and liver TNF-a levels are found in persons with chronic hepatitis C, 10 and viral hepatitis infection induces TNF-a production in human hepatocytes. 11 Nonresponse of chronic hepatitis C to interferon-a therapy has been associated with higher pretreatment TNF-a levels.…”