THE ROLE OF CYCLOSPORINE ON IA-ANTIGEN EXPRESSION ON GUT EPITHELIUM IN NUDE-MICE

Increased expression of class II antigens (HLA-DR, human:la murine) on epithelial cells (EC) such as keratinocytes and gut EC suggests a rol e of the epithelium in the inflammatory response. It has been shown th at injection of normal mouse serum (NMS) into nude mice caused an indu ction of Ia antigen by keratinocytes of the nude mice. The aim of the present study was to determine whether such induction could be observe d in gut EC and whether it can be inhibited by cyclosporine A (CyA). F orty nude mice were divided into 4 groups of 10 each, designated A-D. Group A was injected with 0.1 ml of NMS; groups B and C were also inje cted with NMS and treated with oral CyA for 10 days. The dosage in gro up B was 30 g/ml and in group C 60 g/ml of drinking water. Group D was injected with serum of nude mice and served as a control group. Biops ies of small intestine and colon were obtained from each mouse and ana lyzed by indirect immunoperoxidase to identify Ia expression. Small in testine and colon EC were induced to express Ia antigen in most of the mice in groups A and B. A striking reduction in Ia expression was not ed in group C. The differences between groups A and C concerning Ia ex pression on small intestine and colon EC were statistically significan t. Our results demonstrate that the nude mouse may serve as a model fo r the study of Ia expression on gut EC, and that CyA can suppress the expression of Ia antigen also in the gut.