Lymphocytes isolated from recipients of hepatitis B vaccine were studied for their immune response to HBsAg in uitro. Peripheral blood mononuclear cells (PBMs) from 70 to 80% of 40 vaccinees yielded proliferative indices larger than 2 after 5 to 7 days incubation with HBsAg. This in uitro proliferative response could be augmented by incubating the cells with HBsAg and supernatants of activated T cells for 2 weeks or longer. After 7 to 10 days, in vitro stimulation with antigen, PBMs (1 x lo8) could yield 5 to 15 HBsAg-specific antibody-secreting plaqueforming cells. The antibody to HBsAg produced in vitro was greatly increased in cultures that contained antigen-specific B cells enriched by panning with HBsAg-coated plates and a T cell growth factor-dependent, HBsAg-specific autologous T cell line. The results indicate that HBsAgspecific B and T cells are present, although at low frequencies, in the circulation of hepatitis B vaccinees.
Hepatitis B still remains the most serious infectious liver disease (1, 2). Contributing to this problem is that some individuals fail to mount an effective immune response to hepatitis B virus (HBV) infection and become chronic carriers of the virus (3). It is important to study how the various components of the immune system of normal individuals and HBV-bearing patients respond to the virus and its components. Such studies will help in understanding the pathology of hepatitis B and improving prevention methods.
The induction of most immune responses are known to involve complicated interactions between immunocyte subsets and regulatory factors. In recent years, the studies on the regulation of immune responses have been advanced greatly by analyzing responses of immunocytes under defined conditions in uitro (e.g., 4-6). Of interest is to examine in the in uitro systems whether the variation in the ability of individuals to respond to HBV infection lies in differences in certain regulatory mechanisms. The studies of Chisari et al. (7, 8), Alexander et al. (9) and Mondelli et al. (10) on the analysis of the involvement of cytotoxic and suppressor T cells in hepatitis B are excellent examples of these in uitro studies.
Because the production of antibodies against HBsAg plays a major role in the immune response against HBV ~