title: CD4+ T cells mediate superantigen-induced abnormalities in murine jejunal ion transport.
abstract: The immunomodulatory properties of bacterial superantigens (SAgs) have been defined, yet comparatively little is known of how SAgs may affect enteric physiology. Staphylococcus aureus enterotoxin B (SEB) was used to examine the ability of SAgs to alter epithelial ion transport. BALB/c mice, severe combined immunodeficient (SCID, lack T cells) mice, or SCID mice reconstituted with lymphocytes or CD4+ T cells received SEB intraperitoneally, and jejunal segments were examined in Ussing chambers; controls received saline only. Baseline short-circuit current (Isc, indicates net ion transport) and Isc responses evoked by electrical nerve stimulation, histamine, carbachol, or forskolin were recorded. Serum levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were measured. SEB-treated BALB/c mice showed elevated serum IL-2 and IFN-gamma levels, and jejunal segments displayed a time- and dose-dependent increase in baseline Isc compared with controls. Conversely, evoked ion secretion was selectively reduced in jejunum from SEB-treated mice. Elevated cytokine levels and changes in jejunal Isc were not observed in SEB-treated SCID mice. In contrast, SCID mice reconstituted with T cells were responsive to SEB challenge as shown by increased cytokine production and altered jejunal Isc responses that were similar to those observed in jejunum from SEB-treated BALB/c mice. We conclude that exposure to a model bacterial SAg causes distinct changes in epithelial physiology and that these events can be mediated by CD4+ T cells.
authors.affiliation: Intestinal Disease Research Program, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.
authors.forename: D M
authors.initials: DM
authors.lastname: McKay
authors.forename: M A
authors.initials: MA
authors.lastname: Benjamin
authors.forename: J
authors.initials: J
authors.lastname: Lu
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D004768:Enterotoxins / Q000633:toxicity*; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis / Q000097:blood; D007376:Interleukin-2 / Q000096:biosynthesis / Q000097:blood; D007408:Intestinal Absorption / Q000187:drug effects* / Q000276:immunology; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D007477:Ions; D007583:Jejunum / Q000187:drug effects* / Q000276:immunology / Q000502:physiology; D008213:Lymphocyte Activation; D017710:Lymphocyte Transfusion; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D009195:Peroxidase / Q000378:metabolism; D013154:Spleen / Q000187:drug effects / Q000276:immunology; D013211:Staphylococcus aureus; D018089:Superantigens / Q000633:toxicity*
chemical_list: D002712:Chlorides; D004768:Enterotoxins; D007376:Interleukin-2; D007477:Ions; D018089:Superantigens; C031818:enterotoxin B, staphylococcal; D007371:Interferon-gamma; D009195:Peroxidase; D002118:Calcium