DETECTION OF TUMOR-ASSOCIATED ANTIGENS IN SERA OF CANINE CANCER-PATIENTS BY MONOCLONAL-ANTIBODIES GENERATED AGAINST CANINE MAMMARY-CARCINOMA CELLS

Two murine monoclonal antibodies (MAbs), 1A10 and SB2, generated again st a canine mammary carcinoma cell line, were used in a competitive en zyme-linked immunosorbent assay (ELISA) to measure tumor-associated an tigens (TAAs) in canine serum samples. Sera were tested from disease-f ree dogs and from dogs diagnosed with mammary carcinoma, non-mammary c arcinoma, sarcoma, benign mammary tumor, benign non-mammary tumor, or non-neoplastic disease. Serum antigen concentrations measured by ELISA were expressed as inhibitory units (IU). The upper limit of normal, d efined as the mean plus 2 SD of the TAA concentration in disease-free dogs, was 20 IU with antibody 1A10 and 22 IU with antibody SB2. Compar ed with disease-free dogs, the frequency of TAA-positive sera was sign ificantly greater (P < 0.05) among dogs with mammary or non-mammary ca rcinoma when tested with MAbs 1A10 or SB2, and also with sarcoma when tested with MAb SB2. Testing a serum sample with both antibodies rathe r than just one increased the sensitivity of the competitive ELISA for TAA detection. The presence of TAA in serum might serve as a useful m arker for certain types of carcinomas or sarcomas in canine cancer pat ients.