Lymphocyte activation by low doses of cyclosporin A.

Supernatants of human lymphocyte cultures incubated with cyclosporin A (CS-A) for 90 min reveal an inhibitory effect on the electrophoretic mobility of guinea-pig macrophages. This effect is distinctly demonstrable already at CS-A concentrations from 10-7 micrograms/ml on with a maximum at 10-3 micrograms/ml. An inhibitory action of CS-A on PHA-induced lymphocyte proliferation is detectable only beyond 10-2 micrograms/ml CS-A. The CS-A induced lymphokine is comparable to that stimulated by other ways (PHA, ConA).