Abstract: | During multiple in vitro allosensitisations of human lymphocytes, suppressor cells of the allogenic response are developed. They are radioresistant and specific to the HLA-DR presented by the stimulators, and adherent to nylon and glass wool, while cytotoxic cells are not. Moreover when irradiated, these hyperimmunized cells are able to release a suppressor factor (SF). This suppressor factor is non antigen specific and active on the autologous producer and some allogenic responders. There is a restriction phenomenon, the genetic control of which is not yet defined. The dominant effect of multiple transfusions on kidney graft survival could be explained in part by a similar cellular mechanism. |