Sidedness of the reaction to beta-lactoglobulin in sensitised colonic epithelia.

The short circuit current reaction to beta-lactoglobulin shown by the epithelial lining of the colon from guinea-pigs fed with cows' milk is elicited only when the challenge is applied to the basolateral side of the tissue. However if the apical surface of the epithelium is subjected to controlled lesioning with ultraviolet irradiation then apical challenge with beta-lactoglobulin becomes effective. A similar situation ensues when preparations are aged in vitro at room temperature in oxygenated Krebs-Henseleit solution. Although irradiation causes insignificant changes in the electrical resistance of the tissue, the evidence suggests that it allows beta-lactoglobulin to penetrate the epithelium from the apical side. If the model is applicable to clinical conditions of food allergic disease then it appears that concomitant changes in epithelial permeability as well as the development of sensitivity are required.