Differential Radiosensitivity of First and Second-set Responses to Allogeneic and Xenogeneic Skin Grafts in Sublethally Irradiated Mice.

Data are presented demonstrating the differential radiosensitivity of the first and second-set responses of sublethally irradiated (670 rad) mice previously sensitized with allogeneic (H-2 difference), xenogeneic (rat) or both allogeneic and xenogeneic skin grafts: The secondset response is more radioresistant than is the first-set response; the second-set response to a xenogeneic graft remains intact during and following recovery from the effects of sublethal irradiation; while intact for a brief period following irradiation, the second-set response to an allogeneic skin graft was abrogated by sublethal irradiation (670 rad); concurrent pre-sensitization with allogeneic and xenogeneic skin grafts prevented the abrogation of the second-set response to the allogeneic graft by sublethal irradiation; the first-set response to an allogeneic graft recovered from the effects of sublethal irradiation prior to the recovery of the first-set response to a xenogeneic graft.