Regulation of in vitro primary anti-DNP antibody production by functional subsets of T lymphocytes in man.

A primary in vitro antibody response to DNP-KLH by peripheral blood lymphocytes in culture was developed. Optimal anti-DNP antibody production, as measured by solid phase radioimmunoassay occurred at a cell density of 1 X 10(6), and an antigen concentration of 5 to 10 micrograms per culture when PBL was incubated with the antigen for 5 days and then cultured in the absence of DNP-KLH for 4 additional days. The antibody produced was shown to be primarily of the IgM isotype and was specific for DNP. In the absence of T lymphocytes, no antibody was generated. The regulatory effects of T4+ and T5+/T8+ subsets on antigen-specific antibody production were determined and it was found that T4+ subset alone provided help for anti-DNP antibody production. In contrast, the T8+ subset did not provide help and more importantly, could suppress anti-DNP antibody production in the presence of T4+ inducer T cells. This in vitro antibody forming system should be of considerable use in the analysis of the cellular requirements for antibody production and genetic control of the immune response in man.