title: TCR-mediated involvement of CD4+ transgenic T cells in spontaneous inflammatory bowel disease in lymphopenic mice.
abstract: Spontaneous colitis resembling ulcerative colitis developed in 3 of 10 independent TCR transgenic (Tg) mouse lines maintained under specific pathogen-free conditions. All three susceptible lines were CD4 lymphopenic, whereas resistant lines had normal numbers of CD4+ T cells. Thus, cytochrome c-specific 5C.C7 TCR Tg mice developed colitis only when crossed onto a SCID- or Rag-1-deficient background. A second line of lymphopenic cytochrome c-specific Tg mice bearing the AND TCR also developed colitis. In both cases, CD4+ T cells expressing the Tg-encoded TCR were preferentially activated in inflamed colons compared with lymph nodes or spleens. In contrast, Tg+CD4+ T cells remained quiescent in both inflamed and unaffected colons in another line of susceptible Tg mice carrying a TCR specific for myelin basic protein, suggesting a fortuitous cross-reactivity of the IEk-restricted cytochrome c-reactive AND and 5C.C7 TCRs with an Ag present in the gut. The percentage of CD4+ T cells expressing only endogenous TCR alpha-chains was increased consistently in inflamed colons in AND as well as 5C.C7 Rag-1-/- TCR Tg mice, suggesting that polyclonal CD4+ T cells were also involved in the pathogenesis of spontaneous colitis. Moreover, our data indicate that some alpha-chain rearrangement was still occurring in TCR Tg mice on a Rag-1-/- background, since activated CD4+ T cells expressing endogenously rearranged alpha-chains paired with the Tg-encoded beta-chain were detected consistently in the colons of such mice.
authors.affiliation: Centenary Institute of Cancer Medicine and Cell Biology, Newtown, Australia.
authors.forename: W P
authors.initials: WP
authors.lastname: Koh
authors.forename: E
authors.initials: E
authors.lastname: Chan
authors.forename: K
authors.initials: K
authors.lastname: Scott
authors.forename: G
authors.initials: G
authors.lastname: McCaughan
authors.forename: M
authors.initials: M
authors.lastname: France
authors.forename: B
authors.initials: B
authors.lastname: Fazekas de St Groth
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015704:CD4 Antigens / Q000235:genetics*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D003093:Colitis, Ulcerative / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D004195:Disease Models, Animal; D016654:Genes, RAG-1 / Q000276:immunology; D020022:Genetic Predisposition to Disease / Q000276:immunology; D018398:Homeodomain Proteins / Q000235:genetics; D016130:Immunophenotyping; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics* / Q000502:physiology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism / Q000473:pathology
chemical_list: D015704:CD4 Antigens; D018398:Homeodomain Proteins; D016693:Receptors, Antigen, T-Cell, alpha-beta; C064658:RAG-1 protein