title: Activation of T lymphocytes by syngeneic murine intestinal smooth muscle cells.
abstract: OBJECTIVE
  Intestinal smooth muscle cells (ISMCs) express major histocompatibility complex II (MCH II) and intercellular adhesion molecule 1 (ICAM-1) after exposure to interferon gamma (IFN-gamma). T lymphocytes invade the intestinal musculature during Crohn's disease or pseudoobstruction. The aim of this study was to determine whether ISMCs activate syngeneic T cells via MHC II and ICAM-1.
  
  
  METHODS
  Cultured murine ISMCs were exposed to IFN-gamma for 72 hours and analyzed for Mac-1 (CD11B CD18) antigen, MHC II, and ICAM-1 expression using enzyme-linked immunosorbent assay and fluorescence-activated cell sorter scan. T lymphocytes from mesenteric lymph nodes of ovalbumin-sensitized mice were examined for their ability to proliferate after coculture with IFN-gamma-pretreated and ovalbumin-pretreated ISMCs using [3H]thymidine incorporation.
  
  
  RESULTS
  ISMCs expressed smooth muscle alpha-actin before and after IFN-gamma exposure. No macrophages were identified in these cultures. Exposure to IFN-gamma and ovalbumin for 72 hours induced MHC II and ICAM-1 expression; these treated ISMCs induced T-cell proliferation, whereas untreated ISMCs did not. T-cell proliferation was markedly enhanced by adding interleukin 2 and was blocked by antibodies against MHC II and ICAM-1.
  
  
  CONCLUSIONS
  ISMCs activate T lymphocytes in an MHC II-linked manner and thus possess the ability to modulate immune function in the gut.
authors.affiliation: Intestinal Disease Research Programme, McMaster University, Hamilton, Ontario, Canada.
authors.forename: C M
authors.initials: CM
authors.lastname: Hogaboam
authors.forename: D P
authors.initials: DP
authors.lastname: Snider
authors.forename: S M
authors.initials: SM
authors.lastname: Collins
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D007371:Interferon-gamma / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology; D007422:Intestines / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009130:Muscle, Smooth / Q000166:cytology / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma