title: Expression and function of CD59 on colonic adenocarcinoma cells.
abstract: The expression and function of CD59, a 19-25 kDa membrane glycoprotein that inhibits formation of the membrane attack complex of complement, was analyzed on normal and malignant human colonic epithelial cells. Analysis by immunofluorescence demonstrated a weak apical expression of CD59 on normal intestinal epithelium, with an increased expression on adenocarcinoma cells. The expression of CD59 was greatest on tumor cells with poor differentiation. The functional activity of CD59 on human adenocarcinoma cells was investigated using the colonic adenocarcinoma cell line HT29. CD59 on HT29 cells was glycosyl-phosphatidylinositol-linked, and had a molecular mass of 19-25 kDa. HT29 cells expressed approximately four times more CD59 than leukocytes, and showed a high resistance to antibody-dependent complement-mediated lysis. Blocking of CD59 with divalent antigen-binding F(ab')2 fragments of the anti-CD59 monoclonal antibody 1F5 resulted in a dose-dependent increase in complement-mediated lysis, suggesting that CD59 may be of importance in protecting colonic adenocarcinoma cells against complement-mediated cytolysis.
authors.affiliation: Department of Microbiology and Immunology, Gade Institute, Bergen, Norway.
authors.forename: L
authors.initials: L
authors.lastname: Bjørge
authors.forename: C A
authors.initials: CA
authors.lastname: Vedeler
authors.forename: E
authors.initials: E
authors.lastname: Ulvestad
authors.forename: R
authors.initials: R
authors.lastname: Matre
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology*; D015703:Antigens, CD / Q000096:biosynthesis / Q000276:immunology*; D015153:Blotting, Western; D018957:CD59 Antigens; D015179:Colorectal Neoplasms / Q000276:immunology*; D003169:Complement Inactivator Proteins / Q000096:biosynthesis / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000276:immunology*; D008856:Microscopy, Fluorescence; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010727:Phosphoric Diester Hydrolases; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D018957:CD59 Antigens; D003169:Complement Inactivator Proteins; D008562:Membrane Glycoproteins; D010727:Phosphoric Diester Hydrolases; D043265:Phosphatidylinositol Diacylglycerol-Lyase