Generation of anti-MOPC-315 cytotoxicity in uneducated or in vitro educated spleen cells from normal or MOPC-315 tumor-bearing mice pretreated in vivo with Bacillus Calmette-Guérin.

Cultured spleen cells from normal or MOPC-315 tumor-bearing BALB/c mice that were pretreated in vivo with Bacillus Calmette-Guérin (BCG) exhibited in vitro cytotoxicity against MOPC-315 plasmacytoma. In vitro education of BALB/c spleen cells from normal or tumor-bearing mice by cocultivation with mitomycin C-treated MOPC-315 stimulator cells also resulted in antitumor cytotoxicity. The combination of BCG pretreatment of donor mice with the in vitro education of their spleen cells resulted in a level of anti-MOPC-315 cytotoxicity that was greater than the sum of the levels of cytotoxicity exhibited by spleen cells subjected to either process alone. The levels of cytotoxicity exhibited by educated or uneducated spleen cells from BCG-pretreated mice were dependent on the dose of BCG used and on the time interval between in vivo pretreatment and the initiation of in vitro culture. Thus, our findings suggest that educated spleen cells from tumor-bearing hosts that were pretreated with BCG might be useful in immunotherapeutic regimens requiring histocompatible cells with augmented antitumor cytotoxicity.