Monoclonal antibody-based ELISA to detect glycoprotein tumor-associated-antigen-specific immune complexes in cancer patients.

This report describes the development and applicability of a tumor-associated-antigen-specific immune complex (IC) detection assay to denote the presence of tumor cells in a cancer host. This assay utilizes a murine monoclonal antibody, AD1-40F4, which was produced to a glycoprotein tumor-associated antigen (TAA). In Western blot, the murine monoclonal antibody recognized a 90-100 kD subunit of the antigen. This antigen is immunogenic in cancer patients and induces formation of endogenous antigen-antibody complexes. Analysis of 250 sera from normal individuals and 419 sera from cancer patients revealed that a significantly (P less than .0005) greater proportion (234/419; 55.9%) of cancer sera was positive for the marker than the normal sera (8/250; 3.2%). The incidence of the 90 kD-TAA-specific-IC was consistently and significantly higher in melanoma (58.5%; 38/65), sarcoma (52.9%; 83/157), and carcinoma of breast (50.9%; 58/114), lung (68.2%; 30/44), and colon (64.1%, 25/39) than in the normal group. The age of serum donors did not affect the incidence of the reactivity. Also, at least in the cancer group the gender of the serum donor did not affect the incidence of the 90 kD-TAA-specific-IC positivity. In a retrospective study where sequential serum samples obtained postoperatively from 105 patients with melanoma were analyzed, the 90 kD-TAA-specific-IC could be detected in 72 (69%) of patients several years before the appearance of clinically detectable disease.(ABSTRACT TRUNCATED AT 250 WORDS)