Mouse hepatoma BW7756, a primary hepatocellular carcinoma of spontaneous origin, has been presently employed as a tumor cell model for the in vitro study of tumor-associated antigen (TAA) cytotoxicity. α-Fetoprotein (AFP) of hepatoma origin and its homologous rabbit antisera, both with and without complement, were utilized in the TAA cytotoxic reaction. The cell killing effect, demonstrated by a cytotoxic antibody assay, was not complement dependent; however, the addition of extrinsic complement potentiated the cytotoxic effect. The target cell specificity of the anti-AFP serum for the target cells was demonstrated by the substitution of mouse leukemia L 1210 cells in lieu of the hepatoma cells. In addition, rabbit anti-AFP serum fractionated into its γ-globulin components retained 90% of its cytotoxic properties. Cytotoxic activity of the antiserum could not be abrogated by absorption with normal mouse cells and repetitive washings of the tumor cells failed to diminish the cytotoxicity. Incubation of the tumor cells in mouse tumor postexcision sera was capable of inhibiting the cytotoxic effect. Finally, immuno-fluorescent localization studies revealed that AFP resided at the cell surface as well as in the cytoplasm of mouse hepatoma cells. The supposition that AFP is membrane-associated with regard to the mouse hepatoma cell is intrinsic to the present report.
ASJC Scopus subject areas
- Immunology and Allergy
- Pathology and Forensic Medicine