Abstract
Xenogenic antibodies with reactivity for surface determinants of the guinea pig line-10 hepatocarcinoma were isolated by using cellular immunoadsorbents prepared by coupling formalin-treated line-10 cells to diethylaminoethyl cellulose. Antibodies prepared in this manner exhibited a high degree of reactivity for line-10 surface determinants. These antibodies also reacted with surface determinants of the syngeneic line-1 hepatocarcinoma. Further specificity of antibody reactivity to the line-10 hepatocarcinoma was accomplished by passage of the antibodies through cellular immunoadsorbents prepared with syngeneic line-1 hepatocarcinoma cells. By direct binding studies, these antibodies showed significantly reduced reactivity for line-1 cells and no reactivity for guinea pig spleen cells or for the unrelated murine EL-4 lymphoma. By a competitive radioimmunoassay, these antibodies reacted only with determinants expressed on the surfaces of line-10 cells and not on syngeneic line-1, L2C, spleen, thymus; or xenogeneic EL-4 cell surfaces. In a similar manner, line-10-associated antigens were detected in ascites fluid derived from line-10 tumor-bearing animals. The sequential use of immunoadsorbents made of antigenically distinct but syngeneic tumor cells made it possible to prepare antibodies with restricted reactivity for line-10-associated antigens and should be applicable to the isolation of "tumor-specific" antibodies in other systems.