Effect of a conjugate of daunomycin and antibodies to rat alpha-fetoprotein on the growth of alpha-fetoprotein-producing tumor cells.

Daunomycin was covalently attached via a dextran bridge to specific antibodies against rat alpha-fetoprotein produced in a horse. The effect of this conjugate on an alpha-fetoprotein-producing tumor was investigated in terms of cytotoxicity and inhibition or retardation of tumor development. Under the experimental conditions used, the covalent conjugate was by both criteria more efficient than either daunomycin alone or a mixture of daunomycin and specific antibodies or a conjugate of daunomycin with horse immunoglobulin. These results show that the conjugate may be useful as a specific cytotoxic agent against alpha-fetoprotein-producing tumors.