Antitumor and therapeutic effects of spleen cells from tumor-bearing mice cultured with T cell growth factor and soluble tumor extract.

Spleen cells of BALB/c mice that had been inoculated with syngeneic plasmacytoma MOPC 104E were cultured for 11 days in T-cell growth factor (TCGF) and ultrasonicated tumor extract (USE). Cultured lymphocytes (MOPC-CL) possessed three-fold more lytic units than normal spleen cells cultured in TCGF without USE (N-CL). Moreover, the in vivo neutralization assay suggested that MOPC-CL were composed of at least two populations, one possessing tumor-specific and the other nonspecific antitumor activity. When 2 X 10(7) of MOPC-CL were administered IP to mice that had been inoculated IP with 10(5) MOPC 104E cells 5 days previously marginal prolongation of survival was observed. This effect was not augmented by the single injection of a larger number (5 X 10(7] of CL, but was augmented by the repeated daily administration for 4 days (from day 5 to day 8 after the inoculation) of the same total number (5 X 10(7] of CL. In addition, IP injection of the streptococcal preparation OK432 before the transfer of CL significantly enhanced the therapeutic efficacy, and resulted in a cure rate of 20%. The mechanism of this combined effect appears to involve the effect of OK432 on interleukin 2 (IL-2) regulation systems in vivo. Our culture system with TCGF and USE and our therapy system with OK432 and CL allow the clinical application of adoptive immunotherapy for the many types of solid cancers.