A new tumor-associated antigen, Tennessee Antigen (TAG), has been isolated from 95 percent of 154 primary human gastrointestinal tumors. Of 208 patients with colorectal carcinoma, 81 percent showed elevated leels of TAG in their serum. In this project, TAG is being isolated from extracts of adenocarcinoma of the human gastrointestinal tract. Monoclonal antibodies (MoAb) against TAG are being produced by the following procedure: Spleen cells from Balb/c mice immunized with TAG fuse with Sp 2/0-Ag 14 cells by means of 30 percent polyethylene glycol to produce hybridomas. Culture fluids from hybridoma are screened for antibodies by enzyme immunoassay. After identifying the cultures producing specific antibodies, the hybridoma cells are grown and cloned by limiting dilution in fluid phase. Lines producing MoAb are injected into Balb/c mice to produce MoAb-containing ascites fluid.The MoAb will facilitate analysis of the structure and genetic origin of TAG. It can be used as part of a panel of MoAb to immunologically type the antigenic expression of colorectal carcinomas. Commercially, MoAb can be used for developing a sensitive radioimmunoassay for diagnosis of colorectal carcinomas. It may be useful in the treatment of human colorectal carcinomas.National Cancer Institute
