Detection of human ovarian tumor-associated antigens by antibodies isolated from ovarian carcinoma ascitic fluid

Ascitic fluid from patients with ovarian epithelial cancer contains large amounts of soluble immune complexes and is a potential source of antibodies and antigens associated with the tumor. The antibodies against tumor-associated antigens were purified from the ascitic fluids of patients with ovarian serous cystadenocarcinoma. These antibodies showed specificity toward ovarian epithelial cancer when tested against ovarian tumor cell lines and paraffin-embedded tissue sections of ovarian cancer. The antigens in sera of patients were separated from IgG and IgG complexes by affinity chromatography and the free antigens were isolated. With the antibodies purified from ascitic fluid, the levels of tumor-associated antigens in sera of 10 patients with serous cystadenocarcinoma and 12 control patients were detected by an enzyme-linked immunosorbent assay. The antigens in patients with ovarian epithelial cancer were 2 to 10 times higher than those in control patients. These studies demonstrate that the antibodies isolated from ascitic fluid detect the tumor-associated antigens on tumor cells as well as the shed antigens present in serum.