Cross-linking of T cell mitogens: effects on B and T cell proliferation and immunoglobulin synthesis.

The T cell mitogens Pa-2, concanavalin A (con A) and its dimeric derivative succinyl-con A, were each cross-linked with the bifunctional reagent dimethyl suberimidate. Although the dose-response curves of these insoluble aggregated products were markedly changed from those of the soluble mitogens, each aggregate continued to stimulate DNA synthesis by murine thymus and T cells. Both aggregated Pa-2 and aggregated succinyl con A stimulated DNA synthesis by B cells from athymic (Nu/Nu) mice. Aggregated con A did not stimulate these cells and, like soluble con A, depressed the background incorporation of 3H-thymidine. Unlike soluble Pa-2, aggregated Pa-2 also greatly increased Ig production by both the B cell cultures and B + T cell cultures from normal (BALB/c) mice.