Presence of Hepatitis B Surface Antigen (HBsAg)-Specific Cytotoxic T Cells in Asymptomatic HBsAg Carriers

To investigate whether there is any evidence of an immune stimulation against hepatitis B virus surface antigen (HBsAg) in asymptomatic HBsAg carriers, proliferative and cytotoxic responses to HBsAg were measured in their peripheral blood lymphocytes. Although the majority of asymptomatic carriers had no proliferative response to HBsAg, 3 (25%) of 12 carriers showed significant T cell proliferation against HBsAg. In addition, using HBsAg-expressing autologous lymphoblastoid cell line (LCL) as target cells, HBsAg-specific cytotoxic activity was found in 2 of 3 asymptomatic HBsAg carriers who had a proliferative response against HBsAg. Furthermore, 6 cytotoxic T lymphocyte (CTL) clones were isolated from 1 asymptomatic carrier