Antitumor Antibody Synthesis In Vitro Induced in Mouse Spleen Cells by Xenogeneic Immune RNA

Globulins derived from culture medium and cell lysates that had been prepared from normal, nonimmune C3H mouse spleen cells, following incubation with xenogeneic immune RNA (I-RNA), contained antitumor antibody activity. Globulins derived from spleen cells incubated with I-RNA extracted from the lymphoid organs of guinea pigs that had been immunized with either of two cross-reacting chemically induced C3H mouse sarcomas reacted against target cells of both tumors, but not against target cells derived from a spontaneously arising syngeneic osteosarcoma. Globulins obtained from spleen cells that had been incubated with I-RNA from guinea pigs immunized either with osteosarcoma cells or cells from a spontaneous C3H mouse mammary tumor reacted with target cells from either of the two chemically induced sarcomas, although globulins from spleen cells that had been incubated with antlosteosarcoma I- RNA did not react with osteosarcoma target cells. Globulins derived from spleen cells incubated with I-RNA extracted from guinea pigs that had been immunized with either complete Freund's adjuvant only or with a pool of normal C3H mouse tissues exhibited no reactivity against any of the three target cells tested. The antitumor antibodies whose synthesis was induced by xenogeneic I-RNA were apparently specific for the particular tumor used to immunize the I-RNA donor.