Serum antibody responses to an ascitic variant of rat hepatoma D23

Antibody was detected by membrane immunofluorescence tests in sera of rats bearing an ascitic variant of a transplanted hepatoma, and in concentrated cell-free ascitic fluid. Ascites hepatoma cells were also shown to have immunoglobulin, possibly tumour specific antibody, bound to their surface. The kinetics of antibody responses to ascites hepatoma and hepatoma cells from solid tumours were compared: both tumour types gave positive reactions by the third day after implantation; antibody was present throughout subsequent tumour growth with the ascites whereas antibody was not detected after tumour became palpable in rats injected with hepatoma cells from solid tumour. Antibody responses to ascites tumour were investigated in rats bearing solid hepatoma tumour. Subcutaneous hepatoma did not influence the antibody response to ascites, but rats bearing intraperitoneal tumours showed a diminished serum antibody response to ascitic hepatoma.