The use of cellular immunoadsorbents to prepare antibody that distinguishes between syngeneic surface antigens on two guinea pig hepatocarcinomas.

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.