The effect of cyclosporine on humoral and cellular alloreactivity to allogeneic pregnancy in rats.

We have evaluated the effect of a therapeutic dose (10 mg/kg/day) of the immunosuppressant cyclosporine (CsA) on humoral and cell-mediated immunity in rats during an allogeneic first pregnancy. Virgin female Lewis rats mated with DA males and treated with CsA vehicle produced a humoral response, as measured by both the erythrocyte rosette inhibition (EAI) and indirect hemagglutination assays. The capacity of Lewis splenocytes to mediate a graft-versus-host (GVH) reaction in six-week old F1 (Lewis X DA) hybrid rats was unaffected by either pregnancy or CsA. In mothers treated with CsA, however, no antibody production was detected, and a significant reduction in GVH reactivity was observed using their cells. This reduction was specific for the paternal strain. When compared with vehicle-treated primiparas, suppression of the immune response by CsA had no effect on either the number or viability of fetuses present in utero at day 20. These data suggest that antipaternal antibodies may not be essential to protect the fetus when there is concomitant suppression of the capacity of the mother's T cells to express a cell-mediated antipaternal response.