ICAM-1 co-stimulation has differential effects on the activation of CD4(+)and CD8(+) T cells

T cells play a central role in the initiation, maintenance and regulation o f the immune response. Effector responses of T cells are controlled by comp lex combinations of lymphokines and adhesion/co-stimulatory molecule signal s. To isolate the effects of the adhesion/ co-stimulatory molecule ICAM-1,w e have stimulated purified murine CD4(+) and CD8(+) T cells with plate-boun d anti-CD3 in the presence or absence of plate-bound soluble ICAM-1. In thi s report, we demonstrate that the co-immobilization of soluble ICAM-1 and a nti-CD3 leads to a much greater increase in IL-2 production by CD8(+) T cel ls than CD4(+) T cells. The ICAM-1-induced enhancement we observed has diff erential sensitivity to LFA-1 blockade, depending on the T cell subsets and cytokine evaluated. These effects may play an important role in the genera tion and modulation of immune responses.