696 ESTABLISHMENT OF AN ANIMAL MODEL OF OVALBUMIN - SENSITIZED MOUSE TO STUDY PROTEIN INTOLERANCE IN VITRO

Abstract

Protein intolerance, such as cow's milk allergy, represents a common cause of enteropathy in infancy. However, no reliable laboratory test for the diagnosis is presently available. An animal model of ovalbundn (OVA) - sensitized mouse has been established to study the response of the small intestinal mucosa in organ culture. A decrease of γ-glutamyltranspeptidase (γ-GT), alkaline phosphatase (AlPase), sucrase (S), lactase (L) and glucoamylase (GA) activities was observed in the explants (T) cultured during 24 hours in presence of OVA. In contrast, a large increase of these enzymatic activities was noted in the culture media (M), the overall effect observed beeing a net stimulation of the total enzymatic activities of the culture system. During the same period, a 20% decrease in 3H-thymidine incorporation into DNA was noted (P< .005). Results (X ± S.E.M.) from 12 experiments are expressed as % of activity with respect to autocontrols cultured in presence of β-lactoglobulin. The enzymes accumulated mainly in the particulate fraction of the culture medium (brush border membrane fraction) suggesting an increased turn-over of some membrane components by a process of shedding or microvesiculation. This animal model represents a useful tool to evaluate the modifications of the small bowel mucosa induced by an allergen and to establish the criteria for an in vitro diagnosis of protein intolerance. * Supported by the Medical Research Council of Canada, Grant MT-3320