Stimulation of a human B-lymphocyte line by anti-immunoglobulin and its concanavalin A-induced suppression by a T-cell line.

The effect of anti-immunoglobulin (anti-Ig) on cultures of established human B-cell lines was studied to develop models for the initiation and regulation of immune responses. DNA synthesis in one line, BM, measured by [125I]iododeoxyuridine (IUdR) incorporation, was stimulated by anti-Ig when the continuously proliferating cultures approached high cell density. One of four lines, BJAB, was very sensitive to inhibition of DNA synthesis by anti-Ig at all cell concentrations. Of four human T-cell lines tested for suppressor activity, the CEM line was found to be activated by concanavalin A (Con A) to inhibit the anti-Ig stimulation of BM cells. No cytotoxic activity was detected in Con A-treated CEM cells. Both the anti-Ig stimulation of BM and Con A-induced suppression by CEM occurred with cloned cell lines in long-term culture, in the absence of helper or accessory cells.