HEPATITIS-B VIRUS-SPECIFIC CYTOTOXIC T-LYMPHOCYTE RESPONSES IN PATIENTS WITH ACUTE AND CHRONIC HEPATITIS-B VIRUS-INFECTION

An in vitro model was developed that allowed the analysis of hepatitis B virus-specific cytotoxic T lymphocyte responses in patients sufferi ng from acute and chronic hepatitis B virus infections. Since virus-sp ecific cytotoxic T lymphocytes recognize endogenously synthesized and processed antigen only when it is presented in the context of autologo us KLA class I molecules and since hepatitis B virus does not infect h uman cells in vitro, a panel of recombinant vaccinia viruses was const ructed to induce the expression of hepatitis B virus envelope and nucl eocapsid proteins in cultured primary cells or cell lines derived from the patients to be studied. In order for a cytotoxic T lymphocyte res ponse to be detectable with the currently available techniques, a suff icient number of activated cytotoxic T lymphocytes is required. To mee t this requirement, lymphocytes freshly isolated from venous blood wer e stimulated in vitro with recombinant vaccinia-infected and formaldeh yde-fixed autologous T lymphoblasts. The presence of hepatitis B virus -specific cytotoxic T lymphocytes, amplified and activated during this induction culture, was demonstrated in a microcytotoxicity assay usin g Cr-51-labeled, recombinant vaccinia-infected Epstein-Barr virus-immo rtalized, autologous B lymphocytes as target cells. Using this in vitr o model, we were able to demonstrate the presence of hepatitis B virus envelope- and nucleocapsid-specific cytotoxic T lymphocytes in venous blood from one subject who had recently recovered from an acute hepat itis B virus infection and in three patients suffering from chronic he patitis B virus infections. No hepatitis B virus-specific cytotoxic T lymphocytes activity was discernible in the venous blood from two vacc ine recipients. Antibody-blocking experiments showed the HLA class I r estricted nature of target cell recognition. (C) Journal of Hepatology .