Implantation of cultured thymic fragments in athymic nude rats: studies on tolerance towards donor haplotype.
We previously observed that nude rats after implantation of cultured thymic fragments (CTF) of allogeneic origin manifest in vitro alloreactivity to the donor haplotype, but not to host haplotype. We here extend preliminary data that this in vitro alloreactivity is not accompanied by in vivo rejection of skin transplant from donor CTF origin. This discrepancy between in vivo and in vitro alloreactivity may suggest the presence of peripheral in vivo suppressive mechanisms, which are not active in in vitro assay systems. After implantation of CTF from two different allogeneic strains, however, skin transplants of either one of the donor strains are rejected. We conclude that education of both types of alloreactivity has occurred in the respective CTF's. This latter observation indicates that the suppressive mechanisms hypothesized above, if existent at all, obviously are not sufficiently potent to suppress the alloreactivity which has been generated in a CTF which expresses MHC antigens irrelevant to the alloreaction inducing determinants. If the tolerance to donor CTF is not due to a peripheral tolerance/suppression, it might bear relation to events occurring during precursor T-cell processing in the grafted CTF. The state of chimaerism in the graft reported earlier may explain this tolerance.
Schuurman
H J
HJ
Department of Pathology, University Hospital, Utrecht, The Netherlands.
Rozing
J
J
Broekhuizen
R
R
Tielen
F
F
van de Bergh
P
P
D000818:Animals; D002678:Chimera; D006084:Graft Rejection / Q000276:immunology; D006239:Haplotypes; D007108:Immune Tolerance; D007114:Immunization; D008297:Male; D010047:Ovalbumin / Q000276:immunology; D051381:Rats; D011914:Rats, Inbred BN; D011923:Rats, Nude; D016038:Skin Transplantation / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology / Q000637:transplantation*; D014184:Transplantation, Homologous
D010047:Ovalbumin