title: Cytotoxic activity of V beta 8+ T cells in Crohn's disease: the role of bacterial superantigens.
abstract: In Crohn's disease, disease-related stimuli could alter the T cell receptor (TCR) repertoire. To examine the possibility that changes in function may occur in T cell subsets without obvious changes in expression of TCR, we analysed the TCR repertoire of cytotoxic T lymphocytes in Crohn's disease peripheral blood. Furthermore, we examined the effect of bacterial superantigens, staphylococcal enterotoxin B (SEB) and E (SEE) on the cytotoxic function of T cell subsets bearing different TCR V genes using MoAbs specific for CD3 and TCR V gene products in a redirected cytotoxicity assay. There was no difference between patients and controls in the cytotoxicity measured in concanavalin A (Con A)-stimulated peripheral blood mononuclear cells (PBMC) with anti-CD3 or with six of seven anti-TCR V gene MoAbs. However, the cytotoxicity of V beta 8 T cells was decreased in Crohn's disease patients. This was not due to a decrease in total or CD8+ T cells expressing V beta 8. Furthermore, in normal subjects, PBMC stimulation with SEE and SEB selectively expanded and increased the cytotoxicity of V beta 8 and V beta 12 T cells, respectively. In Crohn's disease, although SEB stimulation increased the number and cytolytic function of the V beta 12 subset, SEE stimulation failed to increase cytolytic activity of V beta 8+ T cells in spite of the expansion of V beta 8+ T cells. These results suggest that the changes in cytotoxic function observed in V beta 8 T cells in Crohn's patients may reflect previous exposure to a V beta 8-selective superantigen.
authors.affiliation: Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: M E
authors.initials: ME
authors.lastname: Baca-Estrada
authors.forename: D K
authors.initials: DK
authors.lastname: Wong
authors.forename: K
authors.initials: K
authors.lastname: Croitoru
mesh_terms: D003424:Crohn Disease / Q000276:immunology*; D003601:Cytotoxicity Tests, Immunologic; D004768:Enterotoxins / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006801:Humans; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000276:immunology*; D018089:Superantigens / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D004768:Enterotoxins; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens; C049463:enterotoxin E, Staphylococcal; C031818:enterotoxin B, staphylococcal