Cyclosporin A-induced suppression of ongoing IgE antibody formation in the mouse.

Persistent anti-ovalbumin (OA) IgE antibody formation in the mouse was suppressed by oral administration of cyclosporin A (Cy A). Spontaneous anti-OA IgE antibody formation in vitro was also suppressed by Cy A added to the culture. Anti-OA IgG antibody responses in vivo and in vitro were less affected by Cy A. Cy A-induced immunosuppression was T cell-dependent since removal of T cells from the immune spleen cell suspension abolished the Cy A-induced suppression of antibody formation. Supplementing normal spleen T cells resulted in recovery of Cy A-induced suppression of spontaneous antibody formation in vitro. Cy A-induced suppressor T cells carried both Lyt 1 and Lyt 2 surface markers.