Inhibition of T-cell activity by cyclosporin A.

Cyclosporin A (CyA) inhibits early events in the T-cell response. It strongly suppresses the activation of naive T cells by IL1 or IL2 and alloantigen. CyA exerts a selective effect on activated T cells. It inhibits the ability of these cells to release IL2 in response to antigen or mitogen restimulation, at concentration that have no effect on the ability of these same cell populations to respond to IL2 by proliferation. The specific effects of CyA are not limited to T cells, however, and this drug will inhibit IL1 production by lipopolysaccharide W-stimulated PU5-IR cells.