Tumour antigens and alloantigens. II. Lack of association of rat hepatoma-D23-specific antigen with beta 2 microglobulin.

It has previously been shown that the tumour-specific antigen of the chemically-induced rat hepatoma D23 has determinants recognised by alloantisera raised against normal syngeneic liver and spleen. However, no reactions were observed with alloantisera raised against syngeneic erythrocytes suggesting that the alloantigeneic determinant responsible for this cross-reactivity is not a major serologically-defined histocompatibility antigen. This concept has been further examined using a defined turkey anti-rat beta 2 microglobulin antiserum. This antiserum failed to block the binding of syngeneic antihepatoma D23 sera to hepatoma D23 target cells as assessed using membrane immunofluorescence and complement-dependant 51Cr release tests. Furthermore, immune precipitates formed from soluble tumour extracts containing hepatoma D23 specific antigen with turkey anti-rat beta 2 microglobulin failed to generate a tumour-specific antibody response in syngeneic rats althouth a cross-reactive antiserum was produced following immunization of allogeneic rats with the immune precipitate.