title: Dissociation of mouse cardiac transplant rejection and donor alloantigen-specific T cell responsiveness.
abstract: Mouse hearts transplanted into MHC disparate donors are usually rejected 1 week after placement. It is widely accepted that alloantigen-reactive helper T lymphocytes (HTL) and cytotoxic T lymphocytes (CTL) are the key mediators of acute allograft rejection. This report demonstrates that the presence or absence of 'traditional' graft-reactive HTL and CTL is not necessarily related to allograft survival. In these studies, donor/recipient combinations disparate only at MHC or only at minor histocompatibility (mH) loci were employed. Allograft survival was monitored, donor-reactive IL-2 (interleukin-2) producing HTL and CTL were quantified by modified limiting dilution analysis, and serum levels of cytolytic alloantibody were determined. C57BL/10 hearts (H-2b) transplanted into B10.BR (H-2k) recipients (full MHC disparity) enjoyed prolonged survival despite massive infiltration of the allograft by donor-reactive HTL and CTL. IgM, but not IgG, donor-reactive alloantibody was present in the sera of these mice. Hence, traditional IL-2 producing HTL and CTL were not capable of mediating acute graft rejection, nor of providing help for alloantibody isotype switching in this MHC disparate combination. In contrast, C3H/HeN (H-2k) hearts transplanted into B10.BR (H-2k) recipients (mH disparity only) were acutely rejected. Donor-reactive HTL and CTL were rare or not detectable in these recipients, and cytolytic alloantibody was not detectable. Similar observations were made when B10.BR hearts were transplanted into C3H/HeN recipients. Interestingly, treatment of recipients with anti-CD4 monoclonal antibody prevented rejection of mH disparate allografts. Therefore, CD4+ T cells were required for rejection of mH disparate allografts, but this process was independent of detectable IL-2 production or CTL function. Hence, the significance of monitoring 'traditional' T cell functions should be questioned in certain donor/recipient combinations.
authors.affiliation: Department of Surgery, University of Michigan, School of Medicine, Ann Arbor 48109, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Bishop
authors.forename: L A
authors.initials: LA
authors.lastname: DeBruyne
authors.forename: S
authors.initials: S
authors.lastname: Chan
authors.forename: S
authors.initials: S
authors.lastname: Xu
authors.forename: E J
authors.initials: EJ
authors.lastname: Eichwald
mesh_terms: D000818:Animals; D003601:Cytotoxicity Tests, Immunologic; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006084:Graft Rejection / Q000235:genetics / Q000276:immunology*; D006085:Graft Survival / Q000235:genetics / Q000276:immunology; D016027:Heart Transplantation / Q000276:immunology*; D007518:Isoantibodies / Q000096:biosynthesis; D007519:Isoantigens / Q000276:immunology*; D008285:Major Histocompatibility Complex / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008912:Minor Histocompatibility Loci / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism
chemical_list: D000939:Epitopes; D007518:Isoantibodies; D007519:Isoantigens