Differential requirements for the production by a T helper clone of the lymphokines involved in the induction of polyclonal proliferation and differentiation of unstimulated B lymphocytes.

Abstract

Antigen-activated T helper (TH) cells secrete into their supernatant various lymphokines that are able to drive B cells to proliferate and to differentiate into Ig-secreting cells. In this report, we compared the production of these two types of activities by a TH clone. We found that B cell proliferating activity was released by TH cells under conditions in which T cell proliferation and the release of the B cell differentiating activity were totally blocked by anti-L3T4 monoclonal antibody GK1.5. The release of these two activities also dissociated during the reversion of T cells to the resting state after activation with antigen. Two weeks after activation, the T cell clone still secreted B cell proliferating activity, but did not secrete B cell differentiating activity. Three to four weeks after activation, neither activity was produced. The data suggest that the genes coding for these two activities are independently regulated in activated T cells. The implications of these observations concerning B lymphocyte development are discussed.