Effect of PSK on prohibited immunity of splenectomized mice.

The effect of PSK (Krestine, an anti-tumor drug prepared from Coriolus versicolor) on splenectomized experimental animals was investigated. Splenectomy was performed on both a tumor-free control group and a tumor-bearing group. The administration of PSK on the splenectomized control group significantly increased the immune state of the host. In the case of the tumor-bearing group, administration of PSK resulted in restoration of the immune function as observed in the control group. Recovery of the immunological function was accelerated when tumor-bearing animals were splenectomized at the terminal stage. The results suggest that the immunomodulating effects of PSK developed at the time of the splenectomy resulted in anticancer activity.