Immunogenic properties of rat hepatoma subcellular fractions.

Subcellular fractions from an aminoazo dye induced rat hepatoma (D23) were examined for their ability to evoke rejection responses in syngeneic hosts to transplanted tumour cells and to induce the production of humoral antibody. Membrane fractions isolated by zonal centrifugation and displaying an increased activity of tumour specific antigen (Price and Baldwin, 1974), as well as crude membrane fractions and purified tumour cell ghosts, all elicited tumour specific antibody demonstrable by membrane immunofluorescence staining of viable hepatoma D23 cells. Tumour cell nuclei or soluble cytoplasmic protein were, however, lacking in this capacity. Resistance to tumour cell challenge was not observed in rats treated with any of the hepatoma D23 subcellular fractions administered by various routes either alone or in admixture with bacterial adjuvants. These findings are relevant to current views that tumour immunity may be more optimally achieved by inoculation of intact (viable or attenuated) tumour cells.