[Augmentation of antitumor activity of Lactobacillus casei YIT 8018 (LC 9018) in combination with various antitumor drugs].

Augmentation of antitumor activity of Lactobacillus casei YIT 9018 (LC 9018), which strongly inhibits the growth of transplantable allogeneic and syngeneic mouse tumors, in combination with antitumor drugs was investigated. Antitumor drugs used in this study were cyclophosphamide (CY), mitomycin C (MMC), 5-fluorouracil (5-FU) and bleomycin (BLM). The antitumor activity of LC 9018 was augmented by combining 5-FU, MMC or BLM against subcutaneously implanted Meth A and BLM, 5-FU or CY against subcutaneously implanted Sarcoma 180 respectively. Furthermore, combinations with BLM, CY, MMC or 5-FU, BLM, CY, MMC significantly inhibited the growth of intraperitoneally inoculated Meth A or Sarcoma 180, respectively. The combination therapy of LC 9018 with CY significantly prolonged the life span of L 1210-inoculated mouse, while the treatment with LC 9018 alone had no inhibitory effect on L 1210. It was suggested that augmentation of antitumor activity of LC 9018 in combination with CY was due to the inhibition of decrease in the number of peritoneal exudate cells caused by CY injection.