Detection of human ovarian tumor-associated antigens by sandwich enzyme immunoassay.

Immunoglobulin G (IgG) complexes were isolated from the ascitic fluids of patients with serous cystadenocarcinoma of the ovaries, and antiserum against the IgG complexes was raised in rabbits. The antibodies reacting with the tumor-associated antigens were purified after the rabbit antihuman IgG was removed by affinity chromatography on IgG coupled to agarose. The purified antibodies recognized antigens on two human ovarian cell lines and several fresh ovarian tumor specimens, but did not react with nongynecologic tumors. The purified antibodies (IgG) were labeled with alkaline phosphatase, and a noncompetitive enzyme immunoassay was developed to detect the tumor-associated antigens in the sera of patients with ovarian cancer. The levels of tumor-associated antigens detected by this assay were found to be two to four times higher in patients with ovarian cancer than in controls. Levels of tumor-associated antigens were higher in patients with high levels of CA 125, although a direct correlation was not observed with the levels of CA 125 in these patients.