[Preparation and identification of monoclonal antibodies against different epitopes on TAG-72 antigen].

The antigen reacted with mAb B72.3 is tumor associated glycoprotein 72 (TAG-72). It has been shown that TAG-72 has good specificity, and it can bind to TAG-72 expressed in great majority of tumors. We have prepared 2 monoclonal antibodies, named 72-45 and 72-142, against epitopes on TAG-72 antigen different from those reacted with B72.3. The results shown that both antibodies did not react with normal adult and fetus tissues but sweat and sebaceous gland and epithelial cells of small intestine. The mAb 72-45 gave a 100% (20/20) positive reaction in colon cancer and 80% (24/30) positive in lung adenocarcinoma. The mAb 72-142 showed a 40.5% (9/20) positive reaction in colon cancer and 79.5% (27/34) positive in lung adenocarcinoma. The antigenic epitopes to which mAb 72-45 directs is carbohydrate and those to mAb 72-142 is also carbohydrate, but also related to sialo-acid mucin in molecular structure.