PREVENTION BY LIVER-TRANSPLANTATION OF THE GRAFT-VERSUS-HOST REACTION AND ALLOGRAFT-REJECTION IN A RAT MODEL OF SMALL-BOWEL TRANSPLANTATION

In the rat combination of DA (MHC haplotype RT1(av1)) donor into PVG(RT1(c)) recipient, liver grafts are not rejected and allow the acceptance of other organ grafts from the same donor strain. Here we show that an existing DA liver graft allows the acceptance of a DA small bowel graft in the PVG; the liver graft also prevented the graft-versus-host reaction normally associated with small bowel grafting. In addition, a liver graft could suppress the GVHR in F-1 hybrid recipients of parental lymphoid cells, a classic GVHR model. GVHR suppression was immunologically specific and required that donor lymphocytes and liver be of the same strain. Besides their clinical implications, these results demonstrate the capacity of the liver for tolerance induction and suggest that it may play a physiological role in negative selection of T cells.