The IFN-y levels in serum and cultured supernatant of peripheral blood mononuclear cells (PBMCs) were compared after stimulation by HBsAg ad, HBsAg ay and HBcAg among 3 groups of subjects i.e. patients with acute HBV infection, patients with chronic HBV infection and subjects recovered from HBV infection. Uninfected vaccinated group was taken as control. Serum and PBMCs were obtained from 38 individuals between 18-50years of age. PBMCs were separated from heparinised blood by Ficoll-Hypaque density gradient centrifugation technique and cultured in C02 incubator after stimulation by HBV surface and core antigens.