title: De novo autoimmunity to cardiac myosin after heart transplantation and its contribution to the rejection process.
abstract: Allograft rejection is initiated by an immune response to donor MHC proteins. We recently reported that this response can result in breakdown of immune tolerance to a recipient self Ag. However, the contribution of this autoimmune response to graft rejection has yet to be determined. Here, we found that after mouse allogeneic heart transplantation, de novo CD4+ T cell and B cell autoimmune response to cardiac myosin (CM), a major contractile protein of cardiac muscle, is elicited in recipients. Importantly, CM is the autoantigen that causes autoimmune myocarditis, a heart autoimmune disease whose histopathological features resemble those observed in rejected cardiac transplants. Furthermore, T cell responses directed to CM peptide myhcalpha 334-352, a known myocarditogenic determinant, were detected in heart-transplanted mice. No responses to CM were observed in mice that had received an allogeneic skin graft or a syngeneic heart transplant, demonstrating that this response is tissue specific and that allogeneic response is necessary to break tolerance to CM. Next, we showed that sensitization of recipient mice with CM markedly accelerates the rejection of allogeneic heart. Therefore, posttransplant autoimmune response to CM is relevant to the rejection process. We conclude that transplantation-induced autoimmune response to CM represents a new mechanism that may play a significant role in cardiac transplant rejection.
authors.affiliation: Department of Surgery and Immunogenetics, Davies Medical Center, University of California School of Medicine, San Francisco 94114, USA.
authors.forename: E V
authors.initials: EV
authors.lastname: Fedoseyeva
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: P L
authors.initials: PL
authors.lastname: Orr
authors.forename: D
authors.initials: D
authors.lastname: Levin
authors.forename: H J
authors.initials: HJ
authors.lastname: Buncke
authors.forename: G
authors.initials: G
authors.lastname: Benichou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D001324:Autoantigens / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D006084:Graft Rejection / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D016027:Heart Transplantation / Q000009:adverse effects / Q000276:immunology* / Q000473:pathology; D007274:Injections, Intraperitoneal; D051379:Mice; D008805:Mice, Inbred A; D008969:Molecular Sequence Data; D009205:Myocarditis / Q000276:immunology* / Q000473:pathology; D018995:Myosin Heavy Chains / Q000276:immunology / Q000378:metabolism; D009218:Myosins / Q000008:administration & dosage / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D014184:Transplantation, Homologous
chemical_list: D001324:Autoantigens; D010446:Peptide Fragments; D018995:Myosin Heavy Chains; D009218:Myosins