Characterization of anti-tissue factor antibody and its use in immunoaffinity purification of human tissue factor.

Human brain tissue factor apoprotein was recently purified to homogeneity in this laboratory by affinity chromatography utilizing factor VII bound to immobilized anti-factor VII (Anal Biochem 165, 365-370, 1987). A potent polyclonal anti-tissue factor antibody has now been raised to the purified apoprotein. Immunostaining of purified tissue factor with this polyclonal IgG yielded a single major band with an apparent molecular weight of 47,000, which corresponds to the mobility on SDS-PAGE of tissue factor apoprotein. Immunostaining of a crude Triton extract of brain tissue yielded two additional bands, with apparent molecular weights of 54,000 and 40,000 Da. An anti-tissue factor IgG was coupled to Affi-Gel-15 to prepare an immunoadsorbant column. The two additional proteins in the crude Triton extract recognized by Western blotting did not bind to the column. This permitted its use to develop a simple, efficient technique for purification of human tissue factor apoprotein.