THE EFFECT OF IMMUNE COMPLEXES ON GOBLET CELL MUCUS RELEASE: A possible new mechanism of gastrointestinal host defense

Abstract

In previous in vitro studies, we noted that immune complexes prepared in antibody excess and exposed to everted gut sacs consistently stimulated excessive mucus release. In the present study, the effect of immune complexes on mucus release was investigated in intact rats. Complexes (bovine serum albumin (BSA)-rat anti-BSA antibody) formed in two-fold antibody excess were injected at laparotomy into the duodenum of normal rats. Rats injected with BSA or purified anti-BSA antibody served as controls. In comparison to the controls, there was a marked increase (P < 0.01) in percentage of disrupted goblet cells (an index of mucus release) in segments from the intestine of rats exposed to immune complexes in vivo. Similarly, there was a significant increase in radiolabelled (Na235SO4) mucus released into intestinal contents, rinse and mucosal homogenate fluids from rats exposed to immune complexes compared to those from rats exposed to BSA (p < 0.001) or purified rat anti-BSA antibody (p < 0.001) alone. Cholera toxin, used as a positive control, also produced a significant increase in percentage of disrupted goblet cells and in radiolabelled mucus release into each of the fluids tested. These findings strongly suggest that immune complexes can stimulate mucus release in intact rat small intestine; enhanced release of mucus may have an important role in clearing the intestine of immune complexes formed on the surface. (Supported in part by USPHS grants).