Tumor-specific delayed hypersensitivity was transferred to peritoneal exudate cells obtained from unimmunized strain 2 guinea pigs after the peritoneal exudate cells were incubated with RNA-rich extracts from lymphoid tissues of syngeneic guinea pigs previously immunized to either of two antigenically distinct diethylnitrosamine-induced transplantable hepatomas. Tumor-specific delayed hypersensitivity was demonstrated by the inhibition of migration from capillary tubes of the RNA-treated peritoneal exudate cells in the presence of the soluble tumor-specific antigen. The RNA extracts exhibited three distinct peaks corresponding to 4 S, 18 S, and 28 S material when analyzed on sucrose density gradients. Tumor-specific delayed hypersensitivity was not transferred when: (a) RNA extracts were from liver, muscle, or kidney of tumor-immunized guinea pigs; (b) the RNA extracts were from unimmunized syngeneic guinea pigs; (c) the RNA extracts exhibited relatively large amounts of 4 S material on sucrose density gradients as occurs after contact with RNase.
This investigation was supported by NIH Contract 72-3205 from the National Cancer Institute. Presented in part at the Annual Meeting of the American Association for Cancer Research in Atlantic City, N. J., April 13, 1973.