TUMOR-ANTIGENS AND ALLOANTIGENS .1. RELATION OF A RAT TUMOR-SPECIFIC ANTIGEN WITH NORMAL ALLOANTIGENS OF THE HOST STRAIN

It has been shown that tumour‐specific antigen from a chemically‐induced rat hepatoma is capable of binding to immunoadsorbent columns made from the Ig fractions of antisera raised in allogeneic animals against a variety of normal tissues. This reactivity is observed with antisera directed against normal syngeneic liver, spleen and lymph‐node cells but it is not detected in normal sera, F, hybrid sera or an antiserum directed against syngeneic erythrocytes. This phenomenon is specific since soluble extracts of normal syngeneic liver, but not of normal altogeneic liver, are capable of inhibiting the binding of hepatoma‐specific antigen to an immunoadsorbent column of Ig from an allogeneic anti‐normal‐liver antiserum. Syngeneic and allogeneic rats were immunized with immune complexes made from xenogeneic sera, alloantisera or syngeneic immune serum and soluble extracts of normal tissue and affinity‐chromatography‐purified hepatoma‐specific antigen. The resulting sera were examined by means of the membrane immunofluorescence test for reactivity against a panel of syngeneic and allogeneic cells. Xeno‐antisera directed against normal syngeneic tissue precipitated with purified hepatoma antigen and this material generated tumour‐specific antibody following immunization into syngeneic rats. The phenomenon of cross‐reactivity of one chemically‐induced rat hepatoma‐specific antigen with normal syngeneic alloantigens is not a unique phenomenon as preliminary results indicate that two other immunologically distinct hepatomas show similar characteristics. Copyright © 1979 Wiley‐Liss, Inc., A Wiley Company