A mucoprotein with colon-specific determinants.

The tissue specificity of colonic mucoprotein antigen (CMA) was examined to determine whether the antigen might have a role as a tissue marker. The immunofluorescent technique, using a rabbit anti-CMA antiserum, was employed to examine a wide range of tissues. Gastrointestinal mucosae as well as non-gastrointestinal mucin producing tissues were positive; however, non-gastrointestinal reactivity could be eliminated by the appropriate absorptions. Mucoproteins were purified separately from each gastrointestinal anatomic region and used to absorb the antiserum. This analysis demonstrated the existence of a family of mucoproteins with a common gastrointestinal specific determinant(s). Mucoproteins from neighboring regions, as seen by this antiserum, showed a greater structural similarity than did mucoproteins from distant regions. Absorption of the antiserum with ileal or cecal mucoprotein allowed the detection of a colon specific determinant present on CMA.