INDUCTION OF HLA-DR ANTIGEN EXPRESSION ON HUMAN COLONIC EPITHELIUM BY TUMOR-NECROSIS-FACTOR-ALPHA AND INTERFERON-GAMMA

Background: We investigated the effects of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) on HLA-DR expression on human normal colonic epithelium, using an organ culture technique. Methods: Biopsy specimens from normal colonic mucosa were cultured for 24 h with various concentrations of TNF-alpha and/or IFN-gamma. Epithelial HLA-DR antigens were identified by an indirect immunoperoxidase staining method. Results: No expression of epithelial HLA-DR antigens was observed in specimens cultured with medium alone. Concentrations of 10(3) U/ml or higher of TNF-alpha and 10(2) U/ml or higher of IFN-gamma induced expression of HLA-DR antigens in a dose-dependent manner. Expression of KLA-DR was increased in specimens cultured with both TNF-alpha and IFN-gamma compared with those cultured with either cytokine alone. Conclusions: Our findings suggest that both TNF-alpha and IFN-gamma play important roles in regulating the expression of HLA-DR on colonic epithelium in patients with inflammatory bowel disease.