The development of in vitro and in vivo anti-tumor cytotoxicity in noncytotoxic, MOPC-315-tumor-bearer, spleen cells ?educated? in vitro with MOPC-315 tumor cells

Abstract

Spleen cells from mice bearing various sizes of MOPC-315 plasmacytoma tumors were not cytotoxic in the 51Cr release assay or the local adoptive transfer assay. These noncytotoxic spleen cells became cytotoxic, however, upon in vitro cocultivation with MOPC-315 tumor cells. The maximal level of in vitro anti-tumor cytotoxicity (51Cr release) with in vitro “educated” tumor-bearer spleen cells was obtained on the fifth day of the cocultivation and was equal to or lower than the level of cytotoxicity seen with in vitro educated normal spleen cells. On the other hand, the level of in vivo anti-tumor cytotoxicity (Winn assay) achieved with tumor-bearer spleen cells educated in vitro was at least equal to, but usually greater than the level of anti-tumor cytotoxicity obtained with normal spleen cells educated in vitro. Thus, in vitro education can generate anti-tumor cytotoxicity in autochthonous lymphoid cells from tumor-bearing hosts. Such educated histocompatible cells should be useful for immunotherapy regimens that might be applicable to man.