Monoclonal antibodies reacting with colorectal tumours

25 mouse monoclonal antibodies were screened for cell surface reactivity with colorectal tumours using the indirect immunoperoxidase method. Five antibodies of the IgG subclasses were selected. LICR-LON-M8 was raised against human milk fat globule membrane (HMFGM). The remaining four antibodies 48-1, 3-48-2, 77-1, and 8-30-3 were raised against human bladder metastases. M8, 77-1, and 8-30-3 which showed epithelial membrane antigen (EMA) - like reactivity exhibited greater selectivity for colorectal cancer compared with normal colon. M8 and 77-1 are being evaluated for immunoscintigraphy of colorectal carcinoma.