title: Molecular mimicry mediated by MHC class Ib molecules after infection with gram-negative pathogens.
abstract: The development of many autoimmune diseases has been etiologically linked to exposure to infectious agents. For example, a subset of patients with a history of Salmonella infection develop reactive arthritis. The persistence of bacterial antigen in arthritic tissue and the isolation of Salmonella or Yersinia reactive CD8+ T cells from the joints of patients with reactive arthritis support the etiological link between Gram-negative bacterial infection and autoimmune disease. Models proposed to account for the link between infection and autoimmunity include inflammation-induced presentation of cryptic self-epitopes, antigen persistence and molecular mimicry. Several studies support molecular mimicry as a mechanism for the involvement of class II epitopes in infectious disease-induced self-reactivity. Here, we have identified an immunodominant epitope derived from the S. typhimurium GroEL molecule. This epitope is presented by the mouse H2-T23-encoded class Ib molecule Qa-1 and was recognized by CD8+ cytotoxic T lymphocytes induced after natural infection. S. typhimurium-stimulated cytotoxic T lymphocytes recognizing the GroEL epitope cross-reacted with a peptide derived from mouse heat shock protein 60 and recognized stressed macrophages. Our results indicate involvement of MHC class Ib molecules in infection-induced autoimmune recognition and indicate a mechanism for the etiological link between Gram-negative bacterial infection and autoimmunity.
authors.affiliation: Division of Rheumatology, Department of Medicine and The Graduate Program in Immunology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, USA.
authors.forename: W F
authors.initials: WF
authors.lastname: Lo
authors.forename: A S
authors.initials: AS
authors.lastname: Woods
authors.forename: A
authors.initials: A
authors.lastname: DeCloux
authors.forename: R J
authors.initials: RJ
authors.lastname: Cotter
authors.forename: E S
authors.initials: ES
authors.lastname: Metcalf
authors.forename: M J
authors.initials: MJ
authors.lastname: Soloski
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018834:Chaperonin 60 / Q000737:chemistry / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018716:Molecular Mimicry; D012480:Salmonella Infections / Q000276:immunology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D018834:Chaperonin 60; D015395:Histocompatibility Antigens Class I; D016056:Immunodominant Epitopes