title: Species cross-reactive membrane-associated urothelial differentiation antigen.
abstract: An antigen, termed "urothelium membrane antigen" (UMA), confined to urothelium and most abundantly associated with the asymmetric unit membrane of the terminally differentiated luminal cells was identified with a monospecific (absorbed or affinity purified) rabbit antiserum obtained by immunization with membranes from normal bovine urothelium. A cross-species immunofluorescence-positive reaction was observed in normal bladder: Luminal urothelial membrane reacted most intensely. Underlying normal urothelial cells also showed a weaker cytoplasmic reaction. Specific luminal membrane labeling was confirmed by transmission and scanning electron microscopy. Specificity of the anti-UMA differed from the general epithelial reactivity obtained with antibodies to bovine urothelium cytosol. Anti-UMA did not cross-react with keratin, although there was some evidence of a filamentous localization in the cytoplasm of permeabilized cells. UMA was variably expressed by urothelial carcinoma-derived cell lines to a degree apparently related to the degree of cell differentiation, showing the highest positivity on the well-differentiated RT4 and RT112 lines and only a very weak reaction with the anaplastic MGHU-1 (EJ) and T24 lines. On immunoblots, anti-UMA reacted with a peptide of approximately 54,000 daltons.
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000276:immunology*; D002417:Cattle; D002454:Cell Differentiation; D002460:Cell Line; D003429:Cross Reactions; D004848:Epithelium / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D007633:Keratins / Q000276:immunology; D008855:Microscopy, Electron, Scanning; D013045:Species Specificity; D001743:Urinary Bladder / Q000166:cytology*; D001749:Urinary Bladder Neoplasms / Q000276:immunology
chemical_list: D000954:Antigens, Surface; D007633:Keratins