Transfer of Tumor-specific Delayed Hypersensitivity in Vitro to Normal Guinea Pig Peritoneal ExÃodateCells Using RNA Extracts from Sensitized Lymphoid Tissues1

Tumor-specific delayed hypersensitivity was transferred to peritoneal exÃodate cells obtained from unimmunized strain 2 guinea pigs after the peritoneal exÃodatecells 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 hypersensi tivity was demonstrated by the inhibition of migration from capillary tubes of the RNA-treated peritoneal exÃodatecells in the presence of the soluble tumor-specific antigen. The RNA extracts exhibited three distinct peaks corre sponding to 4 S, 18 S, and 28 S material when analyzed on sucrose density gradients. Tumor-specific delayed hy persensitivity 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 rela tively large amounts of 4 S material on sucrose density gra dients as occurs after contact with RNase.