The antitumor effects and effect on cell-mediated immunity of Corynebacterium parvum

The antitumor effects and influence on cell-mediated immunity of Corynebacterium parvum (C. parvum) were studied using C3H/He mice and syngenic mouse ascites hepatoma MH 134 tumor. With the administration of C. parvum alone, a significant antitumor effect was obtained in the group given 0.4mg per day intraperitoneally for 5 consecutive days from the fifth day after transplanting 5x10(5)cells/0.1ml of MH 134 tumor subcutaneously on the back. A significant antitumor effect was also obtained when C. parvum was combined with MF chemotherapy (Mitomycin C 1mg/kg, 5-Fluorouracil 25mg/kg), in the group given MF i.p. on the fifth day and 0.4mg/day of C. parvum i.p. for 5 consecutive days from the seventh day after tumor transplantation. The cell-mediated immunity in these two groups was investigated by using the delayed type hypersensitivity (DTH) and macrophage migration inhibition factor (MIF activity). The results were: no decrease in DTH was shown compared with the tumor-bearing untreated group. MIF activity was marked compared with the tumor-bearing untreated group and tended to persist for a long period. From these findings, it was concluded that C. parvum was an effective immunopotentiator which yeilded an antitumor effect by restoring the cell-mediated immunity of the tumor bearing host. The effect seemed to be enhanced when used in combination with chemotherapy