Quantitative analysis of hepatitis C virus-specific CD8+T cells in peripheral blood and liver using peptide-MHC tetramers

• DOI: 10.1073/pnas.96.10.5692
• Publication Date: 2002-07-26T14:44:19Z
• Authors: Xiao-Song He; Barbara Rehermann; F. Xavier López-L...; Judie Boisvert; Ramsey Cheung; John Mumm; Heiner Wedemeyer; Marina Berenguer; Teresa L. Wright; Mark M. Davis; Harry B. Greenberg
• Keywords: 0301 basic medicine; Hepacivirus; CD8-Positive T-Lymphocytes; Viral Nonstructural Proteins; Flow Cytometry; Peptide Fragments; Recombinant Proteins; 3. Good health; Major Histocompatibility Complex; Epitopes; 03 medical and health sciences; Liver; Antigens, CD; HLA-A2 Antigen; T-Lymphocytes, Cytotoxic

It is believed that the hepatitis C virus (HCV)-specific CD8+cytotoxic T lymphocytes (CTLs) play a role in the development of liver cell injury and in the clearance of the virus. To develop a direct binding assay for HCV-specific CTLs, we generated two peptide-MHC tetramers by using the recombinant HLA A2.1 molecule and A2-restricted T cell epitopes of the HCV NS3 protein. With these reagents we are able to detect specific CD8+cells in the blood of 15 of 20 HLA-A2+, HCV-infected patients, at a frequency ranging from 0.01% to 1.2% of peripheral CD8+T cells. Phenotypic analysis of these specific cells indicated that there is a significant variation in the expression of the CD45 isoforms and CD27 in different patients. A 6-hour incubation of one patient’s blood with NS3 peptides resulted in the activation of the epitope-specific CD8+cells, as indicated by their expression of CD69 and IFN-γ. We also detected NS3-specific CD8+T cells in the intrahepatic lymphocyte population isolated from liver biopsies of two HCV-infected patients. The frequency of these specific CD8+cells in the liver was 1–2%, at least 30-fold higher than in the peripheral blood. All of the intrahepatic NS3-specific CD8+T cells were CD69+, suggesting that they were activated CTLs. Direct quantitation and characterization of HCV-specific CTLs should extend our understanding of the immunopathogenesis and the mechanism of clearance or persistence of HCV.