Tumor-specific skin-reactive antigen solubilized from a syngeneic guinea pig liposarcoma by 3M potassium chloride.

Tumor-specific and skin-reactive antigen of a syngeneic liposarcoma (H-10) of Hartley/F guinea pig was solubilized with 3M potassium chloride and purified by precipitation with 2M ammonium sulfate, followed by Sephadex G-200 gel filtration. The antigenic activity of 7 fractions obtained was estimated by the delayed-type skin reaction elicited in syngeneic animals immunized with H-10 cells admixed with BCG. Accurate relative activity of the fractions comparable to the skin reaction elicited by living H-10 cells was calculated by the parallel line assay method in which the dose-response curves of the fractions are compared with that of living cells. About 30 approximately 50 microgram protein of the 3 fractions eluted slowly from the Sephadex column elicited the skin reaction equivalent to that elicited with 1 X 10(6) of living H-10 cells. Tumor-specific skin reactivity per microgram protein of these 3 fractions was roughly 20 approximately 40 times higher than that of lyophilized cells.