Male skin isografts can induce unresponsiveness in female rats.

Nonsensitized (DA x PVG/c) F1 hybrid female rats regularly accepted male skin isografts. However, almost all F1 females sensitized with male F1 bone marrow cells rejected male skin isografts. Spleen cells taken from sensitized F1 females, either before or after the rejection of male skin isografts, conferred resistance against graft-versus-host (GVH) reactions produced in F1 females by parental PVG/c lymph node cells, but only when the cell donors were male. Repeated injection with bone marrow cells from F1 males failed to cause rejection of established male skin grafts by F1 females. Additional male skin grafts transferred after bone marrow cell injection were also retained. However, if established male skin isografts had been deliberately removed from F1 females before injection of male bone marrow cells, subsequently placed male skin grafts were rejected. Neither spleen cells collected from F1 females bearing established male skin isografts after repeated injection with male bone marrow cells, nor spleen cells obtained from F1 females that had received four consecutive male skin isografts were observed to confer resistance against GVH reactions produced by male PVG/c lymph node cells in F1 female recipients. Splenectomy of prospective F1 female recipients did not confer on them the capacity to reject male skin isografts. These results imply that the placement of a male skin isograft interfered with subsequent attempts to stimulate F1 hybrid females to reject male grafts and to resist GVH reactions produced by lymphocytes from PVG/c males.