Isolation and characterization of Crohn's disease tissue-specific glycoproteins

Two Crohn's disease tissue-specific proteins are identified and purified several thousand-fold from crude tissue extracts by different chromatographic procedures. The two proteins migrate in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as 200-210-kilodalton and 150-160-kilodalton species. They are glycoproteins, as evidenced by their binding to concanavalin A-Sepharose 4B and positive staining with Schiff's reagent. Specific immunoreactivity of the two glycoproteins against Crohn's disease sera was demonstrated by immunotransblot analysis. All but one of the operative specimens of colon or small intestine (or both) from 13 patients with Crohn's disease contained either or both of the proteins; they were not detected in specimens of colon from 5 patients with ulcerative colitis, 1 patient with diverticulitis, 1 patient with ischemic colitis, from the normal bowel segments resected from 3 patients with colon cancer, and from two normal ileal tissue specimens. The two glycoproteins did not react with antihuman IgG, IgM, and IgA, suggesting that they are not immunoglobulins. The purified glycoproteins may provide important leads toward the understanding of the pathogenesis of Crohn's disease.