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.

This content is only available via PDF.