HBV-specific lymphoproliferative and cytokine responses in patients with chronic hepatitis B

Background/Aims: Hepatitis B virus specific T cell reponses are crucial for viral elimination but their nature is not fully understood. Methods: We studied the regulation of proliferation and cytokine production after antigenic stimulation in peripheral blood mononuclear cells from chronically HBV-infected patients and subjects with natural immunity after recovery from an acute infection, Proliferation and production of interferon-gamma, IL-10 and tumor necrosis factor-alpha were determined after stimulation with HBcAg, HBeAg or HBsAg in the absence or presence of IL-12 or neutralizing antibodies to IL-12, interferon-gamma, IL-4, IL-10 or tumor necrosis factor-alpha. Results: Upon stimulation with HBcAg or HBeAg, peripheral blood mononuclear cells from chronic hepatitis B virus patients displayed a clear class-II restricted proliferative response (SI greater than 2.5), Both interferon-gamma (less than 50 IU/ml) and IL-10 levels up to 600 pg/ml were detected, Proliferative or cytokine responses to HBsAg were very weak or absent, Addition of IL-12 to HBeAg-stimulated cultures increased the production of interferon-gamma to more than 200 IU/ml in all patients and slightly increased the production of IL-10, Neutralization of IL-10 increased the HBeAg-induced interferon-gamma production but had no effect on tumor necrosis factor-alpha production, Addition of anti-IL-4 or anti-tumor necrosis factor-alpha had no significant influence on proliferation or cytokine release, Importantly, in both chronic hepatitis B virus patients and naturally immune subjects, IL-12 induced proliferative and interferon-gamma responses in peripheral blood mononuclear cells stimulated with HBsAg. Conclusions: Our data indicate that peripheral blood mononuclear cells from chronic hepatitis B virus patients proliferate and produce interferon-gamma and IL-10 upon HBeAg but not upon HBsAg stimulation, IL-12 augments the HBeAg-induced responses and, additionally, provokes proliferation and interferon-gamma production in HBsAg-stimulated cultures.