Inhibition of mitogen-induced lymphokine production by cyclosporin A

The new antilymphocytic agent Cyclosporin A was found to inhibit the production and/or secretion of migration inhibitory factor (MIF) in human lymphocytes stimulated by Concanavalin A. Preincubation for one hour with the compound, followed by 8 hr restoration period of the cells in absence of the drug, resulted in moderate decrease in MIF synthesis and/or release. Cell viability was not affected. The agent was shown not to interfere with MIF action on the macrophage. We conclude that the molecular mechanism of action of Cyclosporin A is based, at least partially, on a blockade of synthesis and/or secretion of lymphokines from immunocompetent cells.