Cytotoxic T lymphocyte activity to hepatitis B virus DNA-transfected HepG2 cells in patients with chronic hepatitis B

Abstract

Cytotoxic T lymphocyte (CTL) activity for hepatitis B virus (HBV) DNA-transfected HepG2 cells (designated HB3-5), which secrete HBsAg, HBeAg and HBV particles, was investigated in 31 patients with chronic HBV infection (18 chronic hepatitis and 13 asymptomatic carriers). 51Cr-labeled HB3-5 with A2 as a major HLA class I antigen served as target cells and T cells from peripheral blood mononuclear cells as effector cells. The CTL activity was measured by a 51Cr release assay. Patients were divided into two groups, the A2 group bearing HLA-A2 and the non-A2 group not bearing HLA-A2. Chronic hepatitis patients in the A2 group showed increased HBV Ag-specific cytotoxicity compared with that seen in the non-A2 group (5.2 +/- 3.1% vs. 0.9 +/- 1.4%; means +/- SD, P < 0.01). In the A2 group with chronic hepatitis, the cytotoxicity was greater in anti-HBe positive patients than in HBeAg positive patients (8.6 +/- 1.9% vs. 3.4 +/- 2.0%, P < 0.01), and asymptomatic carriers showed less cytotoxicity (0.35 +/- 0.31%, P < 0.001) compared with chronic hepatitis patients. In the non-A2 group, HBV Ag-specific CTL activity was negligible in most patients and thus no differences were found among all patient groups. The HBV Ag-specific cytotoxicity was inhibited by antibodies to CD3, HLA class I and hepatitis B nucleocapsid antigens. Removal of CD8+ cells also resulted in marked decrease in the cytotoxicity. These findings indicate that HBV Ag-specific cytotoxicity reflects liver cell damage and HBeAg/anti-HBe status. Furthermore, our assay system appears to be useful to assess CTL response in patients with chronic HBV infection.