title: The significance of the variety of mechanisms of allograft tolerance.
abstract: The influence of variations in protocol on the induction and early stages of maintenance of allograft tolerance in neonatal rats was studied. Allogeneic bone marrow cells, the anti-recipient activity of which was specifically reduced because of their origin from immunologically tolerant donors, possessed diminished tolerogenic capacity. This was commonly manifested by development of an unreactive state in only one of the two parameters of reactivity--allograft rejection and graft-versus-host reactivity--that were monitored. A similar deviation from the occurrence of unreactivity in both forms that characterizes tolerant rats was observed in animals which had been inoculated with syngeneic thymus cells at the time of induction of tolerance. Attempts to demonstrate a requirement for an extended period of exposure of young rats to semi-allogeneic bone marrow cells before specific unreactivity on the part of host cells became irreversible were unsuccessful.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016026:Bone Marrow Transplantation; D006084:Graft Rejection; D006087:Graft vs Host Reaction; D007108:Immune Tolerance; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D008198:Lymph Nodes / Q000473:pathology; D008214:Lymphocytes / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D016038:Skin Transplantation; D013950:Thymus Gland / Q000637:transplantation; D014181:Transplantation Immunology; D014184:Transplantation, Homologous
chemical_list: D007130:Immunoglobulin Idiotypes