Boosted mucosal immune responsiveness in the rat intestine by actively transported hexose

Anaphylaxis-mediated intestinal fluid secretion was measured in Trichinella spiralis- or ovalbumin-immunized rats challenged intraduodenally with T. spiralis somatic antigen (1 mg protein/0.5 mL saline) or ovalbumin (1 mg/0.5 mL saline), respectively. Intestinal fluid volume was measured 30 minutes after challenge as an index of net secretion. Challenge with the antigenic bolus containing 40 mmol/L D-glucose induced twice the fluid secretion as that induced by either antigen alone. L-Glucose was an ineffective substitute for D-glucose. The enhancement of secretion by D-glucose was dependent on prior immunologic sensitization, was diminished in the presence of phlorizin, and was mimicked by beta-methyl glucoside. Results indicate that the active transport of D-glucose augments the antigen-mediated fluid secretion, possibly by enhancing permeation of the intestinal epithelium to antigen, thereby providing greater access to the mucosal immune system.