Demonstration of tumor-associated immunoglobulin G isolated from immune complexes in ascitic fluid of ovarian cancer.

An analysis was made of the ascitic fluid obtained from a patient with serious cyst-adenocarcinoma of the ovary. The fluid contained no reactivity to rheumatoid factor, carcinoembryonic antigen, and autoantigens. The immune complexes in the ascitic fluid, demonstrated by C1q deviation and characterized by gel chromatography, protein A binding studies, and Ouchterlony diffusion, appeared as high molecular weight material. The monomeric IgG dissociated from this material was capable of reassociation into complexes, as shown by radioactive labelling studies. The IgG isolated from the complexes was localized specifically to autologous as well as heterologous malignant ovarian tumor cells but not to normal ovarian tissue by the immunoperoxidase technique.