A shared and unique peptide in the human colon, eye, and joint detected by a monoclonal antibody

Extraintestinal manifestations of inflammatory bowel disease include involvement of the eye and joint. However, the pathogenesis of ocular and joint complications is unknown. The aim of the current study is to examine the presence of cross-reactive peptide in the colon and ocular and joint tissue.

Using a murine monoclonal antibody (7E12H12; immunoglobulin M isotype) developed against a colon epithelial protein, various parts of the eyes (n = 10) and joints (n = 8) were examined. A sensitive immunoperoxidase assay was used.

In the ocular and joint tissues, the reactivity of 7E12H12 monoclonal antibody was exclusively present in the nonpigmented epithelial cells of the ciliary processes and chondrocytes, respectively. Other structures of the eyeball, such as the sclera, cornea, iris, and retina, and the synovium of the joints did not react with 7E12H12 monoclonal antibody. Colonic epithelial cells examined in parallel also reacted with the monoclonal antibody.

The colon epithelial cells share a unique peptide with the nonpigmented ciliary epithelial cells and chondrocytes. Future studies of the peptide(s) expressing this common epitope shared by the colon and extracolonic organs known to be involved in colitis may provide further understanding of the pathogenesis of extraintestinal complications in patients with ulcerative colitis.