title: Molecular mimicry may contribute to pathogenesis of ulcerative colitis.
abstract: Ulcerative colitis (UC) is a chronic inflammatory bowel disease with mucosal inflammation and ulceration of the colon. There seems to be no single etiological factor responsible for the onset of the disease. Autoimmunity has been emphasized in the pathogenesis of UC. Perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) are common in UC, and recently two major species of proteins immunoreactive to pANCA were detected in bacteria from the anaerobic libraries. This implicates colonic bacterial protein as a possible trigger for the disease-associated immune response. Autoantibodies and T-cell response against human tropomyosin isoform 5 (hTM5), an isoform predominantly expressed in colon epithelial cells, were demonstrated in patients with UC but not in Crohn's colitis. We identified two bacterial protein sequences in NCBI database that have regions of significant sequence homology with hTM5. Our hypothesis is that molecular mimicry may be responsible for the pathogenesis of UC.
authors.affiliation: UMDNJ-Robert Wood Johnson Medical School, Crohn's and Colitis Center of New Jersey, New Brunswick, 08903, USA. kovvalgk@umdnj.edu
authors.forename: Gopala
authors.initials: G
authors.lastname: Kovvali
authors.forename: Kiron M
authors.initials: KM
authors.lastname: Das
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001323:Autoantibodies / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology; D003093:Colitis, Ulcerative / Q000209:etiology* / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D006801:Humans; D008954:Models, Biological; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000276:immunology; D014335:Tropomyosin / Q000737:chemistry / Q000276:immunology
chemical_list: D001323:Autoantibodies; D001426:Bacterial Proteins; D014335:Tropomyosin