title: Localization of CD8 T cell epitope within cardiac myosin heavy chain-α334-352 that induces autoimmune myocarditis in A/J mice.
abstract: BACKGROUND
  Cardiac myosin heavy chain-α (Myhc), an intracellular protein expressed in the cardiomyocytes, has been identified as a major autoantigen in cardiac autoimmunity. In our studies with Myhc334-352-induced experimental autoimmune myocarditis in A/J mice (H-2a), we discovered that Myhc334-352, supposedly a CD4 T cell epitope, also induced antigen-specific CD8 T cells that transfer disease to naive animals.
  
  
  RESULTS
  In our efforts to identify the CD8 T cell determinants, we localized Myhc338-348 within the full length-Myhc334-352, leading to four key findings. (1) By acting as a dual epitope, Myhc338-348 induces both CD4 and CD8 T cell responses. (2) In a major histocompatibility complex (MHC) class I-stabilization assay, Myhc338-348 was found to bind H-2Dd-but not H-2Kk or H-2Ld-alleles. (3) The CD8 T cell response induced by Myhc338-348 was antigen-specific, as evaluated by MHC class I/H-2Dd dextramer staining. The antigen-sensitized T cells predominantly produced interferon-γ, the critical cytokine of effector cytotoxic T lymphocytes. (4) Myhc338-348 was found to induce myocarditis in immunized animals as determined by histology and magnetic resonance microscopy imaging.
  
  
  CONCLUSIONS
  Our data provide new insights as to how different immune cells can recognize the same antigen and inflict damage through different mechanisms.
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Chandirasegaran
authors.initials: C
authors.lastname: Massilamany
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Arunakumar
authors.initials: A
authors.lastname: Gangaplara
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Rakesh H
authors.initials: RH
authors.lastname: Basavalingappa
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Rajkumar A
authors.initials: RA
authors.lastname: Rajasekaran
authors.affiliation: Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Vahid
authors.initials: V
authors.lastname: Khalilzad-Sharghi
authors.affiliation: Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Zhongji
authors.initials: Z
authors.lastname: Han
authors.affiliation: Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Shadi
authors.initials: S
authors.lastname: Othman
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: David
authors.initials: D
authors.lastname: Steffen
authors.affiliation: School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States. Electronic address: nreddy2@unl.edu.
authors.forename: Jay
authors.initials: J
authors.lastname: Reddy
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology*; D016827:CD8 Antigens / Q000276:immunology*; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology; D005260:Female; D016056:Immunodominant Epitopes / Q000276:immunology*; D008279:Magnetic Resonance Imaging; D051379:Mice; D008805:Mice, Inbred A; D009205:Myocarditis / Q000209:etiology / Q000276:immunology*; D018995:Myosin Heavy Chains / Q000276:immunology*; D013194:Staining and Labeling; D001613:beta 2-Microglobulin / Q000276:immunology
chemical_list: D016827:CD8 Antigens; D016207:Cytokines; D016056:Immunodominant Epitopes; D001613:beta 2-Microglobulin; D018995:Myosin Heavy Chains
keywords: Autoimmunity; CD8 T cells; Cardiac myosin; MHC class I dextramers; Myocarditis