Induction of immune responsiveness in a genetically low-responsive tumor-host combination by chemical modification of the immunogen.

Trinitrophenylated Moloney virus-induced YAC cells induced a higher cytotoxic antibody response and better protection against small tumor cell doses in syngeneic, low-responsive strain A mice than nonmodified YAC cells that had been inactivated by irradiation or mitomycin C treatment. The results indicated that genetically determined low responsiveness to a virally induced antigen can be overcome, at least to some extent, by coupling the immunizing cells to a strong immunogenic hapten.