Effects of cyclosporin A (CyA) and methylprednisolone (MP) on the immune response. I. T-cell-activating factor abrogates CyA- but not MP-induced suppression of antigen-induced lymphokine production.

The influence of cyclosporin A (CyA) and methylprednisolone (MP) on the elaboration of the human lymphokine, leukocyte migration inhibitory factor (LIF) was investigated. Both CyA and MP at pharmacological concentrations inhibited the release of LIF from immune lymphocytes challenged by recall antigen. By contrast, the release of LIF in response to polyclonal activation by phytohaemagglutinin A was not affected by CyA or by MP. CyA and MP had no effect on the production of the monokine, T-lymphocyte-activating factor (TAF) by stimulated blood monocytes. However, addition of partially purified TAF to antigen-stimulated lymphocytes completely abrogated the inhibitory effect of CyA, but not that of MP. Thus, CyA and MP affect antigen-induced production of LIF by immune lymphocytes by different mechanisms.