Mucin-like carcinoma-associated antigen defined by three monoclonal antibodies against different epitopes.
Three monoclonal antibodies [MAb], b-8, b-12, and b-15, have previously been shown to react with mammary carcinomas and with a restricted set of cells in normal human tissues [C. Stähli et al., Experientia (Basel), 41: 1377-1381, 1985; H. R. Zenklusen et al., Virchows Arch. Abt. A Pathol. Anat., 413: 3-10, 1988]. They are shown here to recognize the same high molecular weight acid soluble glycoprotein antigen. Lectin binding, biolabeling, and deglycosylation experiments demonstrate that it contains O-linked carbohydrate side chains with sialic acid and hexoses including fucose, galactose, and/or galactosamine but little if any mannose. These properties, typical of mucin-like glycoproteins, agree with the antigen expression on mucin-secreting epithelial surfaces (H. R. Zenklusen et al., Virchows Arch. Abt. A Pathol. Anat., 413:3-10, 1988). The antigen is thus named mucin-like carcinoma-associated antigen (MCA). The three MAb are shown to bind to three different epitopes on MCA. Two of these epitopes (MCA-b-8 and MCA-b-15) are O-linked carbohydrates, and one (MCA-b-15) contains sialic acid. The epitope MCA-b-12 is of peptide nature. Of various two-site sandwich enzyme immunoassays composed of different combinations of the three MAb, the one with MAb b-12 in both positions is selected for a serum assay. Analyses of tumor patients' sera demonstrate that this MCA enzyme immunoassay can be of use as a tumor marker assay for mammary carcinomas. The parameter MCA enzyme immunoassay is shown to differ from other parameters described in the literature.
Stähli
C
C
F. Hoffmann-La Roche and Co., Ltd., Basel, Switzerland.
Caravatti
M
M
Aeschbacher
M
M
Kocyba
C
C
Takacs
B
B
Carmann
H
H
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000032:analysis*; D002241:Carbohydrates / Q000032:analysis; D002277:Carcinoma / Q000276:immunology*; D000939:Epitopes / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008970:Molecular Weight; D009077:Mucins / Q000032:analysis* / Q000276:immunology; D009369:Neoplasms / Q000032:analysis; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D002241:Carbohydrates; D000939:Epitopes; D009077:Mucins