HEPATITIS-C VIRUS-SPECIFIC CYTOLYTIC T-LYMPHOCYTE AND T-HELPER CELL RESPONSES IN SERONEGATIVE PERSONS

Hepatitis C virus (HCV) is a common infection worldwide, and in most p ersons, it leads to persistent viremia and liver damage. Efforts to id entify the correlates of protective immunity are hampered by this high rate of persistent infection in both infected humans and the only ani mal model, the chimpanzee. Peripheral blood mononuclear cells from ser onegative persons were stimulated with synthetic peptides that represe nt epitopes recognized by HCV-specific cytotoxic T lymphocytes (CTL) a fter natural infection. In addition, CD4(+) proliferative responses to recombinant HCV proteins were examined in these same persons. CTL res ponses directed against a peptide epitope of HCV and proliferative res ponses in 2 HCV-seronegative persons with possible occupational exposu re to HCV were found. These otherwise healthy persons were not viremic , suggesting that they may have recovered from acute HCV infection. Ch aracterization of virus-specific immune responses in exposed but seron egative persons may provide important clues as to the nature of protec tive immunity in HCV.