Apparent lack of H-Y-specific suppressor cells in female mice given male spleen cells intravenously.

Mice given a pretransplant i.v. infusion of spleen cells from donors incompatible with the recipients with respect to individual minor H antigens exhibit a delayed rejection of skin grafts from these incompatible donors. Attempts were made to detect suppressor T cells, possibly induced by the i.v. infusion of donor cells, among spleen cells from female mice made hyporesponsive to H-Y antigen by an i.v. infusion of male spleen cells. When transferred to nonimmune immunocompetent mice, lymphoid cells from hyporesponsive females delayed the rejection of male skin grafts only slightly. Similar results were obtained when putative suppressor cells were transferred to immunodeficient hosts having had their potential to reject male skin grafts restored with either nonimmune or specifically immune female lymphoid cells. The observed suppression of graft rejection could be accounted for, to a significant extent, by male spleen cells carried over with the transferred female cells to the assay recipients. Though an active host-derived suppressor mechanisms was not found, transferred spleen and lymph-node cells obtained from females given a prior i.v. infusion of male spleen cells were poor at restoring the capacity to reject male skin grafts to immunodeficient female recipients, whereas equal numbers of lymphoid cells from untreated females were much better. Thus, i.v. infusion of male spleen cells appeared to deplete the peripheral lymphoid tissue of the recipients of responsivity to H-Y antigen.