Regulatory functions of T- and accessory-cells for hepatitis B surface antigen induced specific antibody production and proliferation of human peripheral blood lymphocytes, in vitro.

In vitro assays for lymphocyte proliferation and production of specific antibodies to hepatitis B surface antigen (HBsAg) are described. Peripheral B-cells from healthy donors with acquired immunity after infection with hepatitis B virus (HBV) were activated by purified HBsAg at low concentrations (approximately 2.5 ng/ml), into plasma cell differentiation and maturation to specific immunoglobulin (anti-HBs) secretion. This process was dependent upon and strictly regulated by T-cells and anti-HBs secretion of IgG class was registered at T/B ratios less than or equal to 4.0. Higher T/B ratios provoked secretion of large amounts of total IgM but no specific antibodies. Maximal DNA-synthesis was induced in purified T-cells or the total peripheral blood lymphocyte population from HBV-immune donors at higher concentrations of HBsAg (7-15 ng/ml and 60-125 ng/ml respectively). Proliferation was dependent upon and regulated by monocytic cells. Ten percent of autologous monocytic cells within the cell cultures was optimal, while excessive amounts effectively suppressed the proliferative response. DNA-synthesis was low and extremely shortlived and the induction phase to maximal proliferation for different HBV immune donors varied between 5-8 days in culture.