IDENTIFICATION, PURIFICATION, AND RADIOIMMUNOASSAY OF NB-70K, A HUMAN OVARIAN TUMOR-ASSOCIATED ANTIGEN

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (4) , 1351-1357
Abstract
NB/70K, a tumor-associated antigen of human ovarian epithelial tumor Fraction OCA, was purified and identified as a glycoprotein which is stable in 0.6 M perchloric acid, binds to concanavalin A and migrates electrophoretically with .alpha.-like mobility in barbital-buffered agarose at pH 8.6 NB/70K does not appear to contain normal serum, normal ovary, normal lung or carcinoembryonic antigen-like cross-reacting antigenic determinants as measured by radioimmunoassay. NB/70K was purified from ovarian antigen Fraction OCA by chromatography on .gamma.-globulin coupled to Sepharose 4B and by elution from acrylamide gels. NB/70K migrates as a single band with an apparent MW of 70,000 in sodium dodecyl sulfate:acrylamide gel electrophoresis. A rabbit antibody raised against NB/70K was able to precipitate a polypeptide with a MW of 70,000 as visualized by autoradiography of sodium dodecyl sulfate:acrylamide gels. A radioimmunoassay was developed for measuring NB/70K activity, using Staphlococcus aureus protein A as a precipitating agent.