Delayed cutaneous hypersensitivity to cell-free tumor antigens.

The exposure of two different methylcholanthrene-induced strain 2 guinea pig sarcomas to low-intensity sonic energy provided cell-free extracts that could elicit tumor-specific delayed cutaneous hypersensitivity reactions. These extracts, when fractionated by diethylaminoethyl column chromatography, yielded u partially purified component capable of eliciting delayed cutaneous hypersensitivity reactions in tumor-immunized syngeneic guinea pigs, which reactions were highly specific for the tumor from which the extract was derived. These partially purified antigens, which were derived from tumors induced by the same chemical agent, could thus evoke, in tumor-immunized syngeneic guinea pigs, cellular immune responses that are specific for the immunizing tumor.