Cyclosporin A Inhibits Thymus-dependent but not Thymus-independent Immune Responses Induced by Dextran B512

Abstract

Studies of the immune response to dextran (Dx) B512 in thymus-deficient nu/nu and thymectomized, lethally irradiated and bone marrow-reconstituted mice were compared with those obtained with cyclosporin A (CyA) as a T-cell-inhibiting drug. Only immune responses to TD forms of Dx B512 are susceptible to suppression by CyA, whereas anti-alpha 1-6 and anti-DNP [dinitrophenyl] antibodies induced by high MW dextran and DNP-native Dx, respectively, were not inhibited. Similar results were obtained when polyclonal responses were studied. The polyclonal response induced by another dextran preparation, the polyanion dextran sulfate, was inhibited by CyA to the same extent as polyclonal T-cell activation by T-cell mitogens.