Resting lymphocytes are the target of cyclosporin action

Immunomodulation with Cyclosporin may allow better management of the patient with insulin dependent diabetes mellitus. The cellular effects of CsA were determined on rabbit lymphocytes which are a resting (Go) population for which the kinetics of activation have been defined. Cyclosporin inhibited polyclonal T-cell activation as well as B-cell activation by T-dependent and T-independent antigens. Resting lymphocytes were the exclusive target of CsA. Primed or activated cells, as well as cells in G1, were resistant to the drug. Cyclosporin inhibited the generation of T-helper cells and spared suppressor cell generation. The inhibitory effects of cyclosporin were not reversible.