ENHANCEMENT OF ANTITUMOR RESISTANCE IN MI CE BY MEANS OF ANTIGENIC MODIFICATION OF TUMOR-CELLS WITH RNA PREPARATIONS

Xenogeneic high polymeric RNA was administered intraperitoneally to A/ He mice with syngeneic tumor of the mammary gland (TMG). It caused a r eliable decrease of the tumor growth only in combination with precedin g immunization with RNA-treated TMG cells. Under syngeneic transfer of Krebs-2 tumor cells to CC57BR mice from mice who received <<rat>> RNA , the tumor growth was suppressed in contrast to mice preimmunized wit h rat spleen cells. It is supposed that an, alteration of tumor cell a ntigens due to parenteral RNA injection similar to that observed in th e cells exposed to RNA action in vitro is possible.