AVIDITY FOR ANTIGEN CAN INFLUENCE THE HELPER DEPENDENCE OF CD8-LYMPHOCYTES( T)

To examine the influence of avidity on the helper dependence of CD8+ T cells, purified CD8+ T cells from transgenic mice expressing a TCR sp ecific for H-2K(b) were tested for their responsiveness to spleen cell s expressing different densities of H-2K(b). High avidity interactions resulted in the induction of strong proliferative responses by purifi ed CD8+ T cells. These cells synthesized their own IL-2 and IL-2R. By contrast, low avidity interactions failed to induce proliferation or d etectable IL-2 synthesis, although IL-2R were induced and addition of rIL-2 induced a proliferative response. These results are consistent w ith a model in which TCR avidity for Ag can determine the helper depen dence of a CD8+ T cell.