To obtain the apoptosis in MT2 cells induced by HepG2.2.15 cells expressing Fas Ligand.A human T-lymphotropic virus type I infected cell line MT2 was cultured overnight, then 0.5 ml serum contained hepatitis B virus DNA(HBV DNA), E antigen and S antigen was added to it together with 1 ml of fresh RPMI 1640 medium and incubated for 20-24 hours at 37 degrees C. The cells were washed three times with RPMI 1640 medium without serum, followed by continued incubation. The cells were harvested and Fas antigen were determined by immunohistochemistry. The cells expressed Fas antigen was added to HepG2.2.15 cells expressing Fas Ligand together with fresh RPMI 1640 medium and incubated for 48-72 hours at 37 degrees C. The apoptosis in MT2 cells was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL).The Fas antigen was observed in MT2 cells harvested at 8-12 days post-infected, and the strong signals of apoptosis was observed in MT2 cells incubated together with HepG2.2.15 cells for 48-72 hours.MT2, a human T cell line infected with hepatitis B virus is able to express Fas antigen. The apoptosis in MT2 cells induced by HepG2.2.15 indicated that the T-lymphocyte in the quality of effective cell and the hepatocyte in the quality of target cell could be reversed in the pathogenesis of viral hepatitis.