STRESS PROTEINS IN COLORECTAL MUCOSA - ENHANCED EXPRESSION IN ULCERATIVE-COLITIS

Stress (heat shock) proteins are ubiquitous intracellular proteins tha t can be induced in vitro by physiological stress events that occur du ring inflammation. We have used an indirect immunoperoxidase method to locate 60-kDa stress proteins in biopsies taken from normal and infla med colorectal mucosa. An anti-60-kDa monoclonal antibody (ML30) produ ced specific staining of surface epithelial cells localized to the sit e of the Golgi apparatus. In ulcerative colitis, there was an increase d concentration of this stress protein compared with controls (P less- than-or-equal-to 0.002) and also with a small group of active Crohn's colitis (P less-than-or-equal-to 0.01), but no relationship between it s concentration and disease activity. All biopsies also showed stainin g of goblet cells by ML30, suggesting a possible cross-reaction with m ucin; electroblotting of crude but not purified mucin showed a faint 6 0-kDa band with ML30. We conclude that the 60-kDa stress protein is pr esent in normal colorectal epithelial cells and is markedly induced in vivo in ulcerative colitis. Further, we suggest that since the 60-kDa protein functions as a molecular chaperone, it may associate with col onic mucin aiding in its synthesis and/or secretion.