Initial immunochemical characterization of MX35 ovarian cancer antigen.
Monoclonal antibody (mAb) MX35 reacts with approximately 90% of ovarian epithelial cancers and has been studied in localization and biodistribution trials in ovarian cancer patients. This study shows that mAb MX35 recognizes a cell surface antigen of about 95,000 D on OVCAR-3 ovarian cancer cells. The antigen could be immunoprecipitated from lysates of cells metabolically labeled with [3H]glucosamine and it bound to concanavalin A and wheat germ agglutinin lectins, showing that it is a glycoprotein. MX35 antigen can also be detected in detergent lysates of OVCAR-3 cells by Western blotting. Using this technique the MX35 epitope(s) was shown to be heat stable but susceptible to reduction by 2-mercaptoethanol. Protease digestion of the antigen resulted in smaller fragments (42-52 kDa) that still reacted with antibody. We conclude that MX35 antigen is a 95 kDa glycoprotein, stabilized by disulfide bonds, with a large protease-resistant region that carries the MX35 epitopes.
Welshinger
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Gynecology Service and Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
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Lloyd
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D000951:Antigens, Neoplasm / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D000939:Epitopes; D005260:Female; D006801:Humans; D008970:Molecular Weight; D010051:Ovarian Neoplasms / Q000276:immunology*; D011233:Precipitin Tests; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D000939:Epitopes