Tumor-associated antigens on bovine leukemia virus-induced bovine lymphosarcoma identified by monoclonal antibodies.

Thirteen monoclonal antibodies directed against tumor cells from cattle from enzootic bovine leukosis (EBL) were obtained. They reacted with tumor cells but not with normal bovine cells or bovine leukemia virus antigens. According to the reactivities of these antibodies with 19 individual tumors, the 13 monoclonal antibodies can be divided into three groups. Antibodies of the first group reacted with all the EBLs tested; those of the second group reacted with several, but not all, of the EBLs tested; and those of the third group reacted only with homologous tumor cells. Therefore, tumor-associated antigen (TAA) on the EBL tumor may possess common TAA, partially common TAA, and individually distinct TAA. The TAAs were solubilized from the tumor cells by treatment with 0.2% sodium deoxycholate and partially purified by diethylaminoethyl-cellulose column chromatography. Eleven of the 13 monoclonal antibodies reacted with this soluble TAA. The monoclonal antibodies belonging to the first group inhibited in vitro the growth of the bovine lymphoid cell line derived from the EBL tumor.