Antitumor effect of heat-killed Aspergillus fumigatus mycelium in a mouse model.

A suspension of heat-killed Aspergillus fumigatus mycelium inhibited the growth of a chemically-induced mouse bladder tumor (MBT). Tumor growth was inhibited when the mycelium was injected into mice in a mixture with the tumor cells, when injected into growing tumors, and when introduced IP at the time tumor cells were injected into the hind leg muscle. In the concentrations that affected tumor growth no toxicity of the fungus preparation was observed. The fungal suspension was more effective against MBT than a Corynebacterium parvum strain known to be a potent biologic response modifier. A significant increase in the number of mouse peritoneal exudate cells (PEC) was noted following inoculation with the mycelium. The induced PEC were cytotoxic to the tumor cells in vivo, suggesting that at least part of the tumor inhibition by the mycelium is host-mediated.