engleski

Immunomodulator and antitumor effects of PS-K (krestin)

The antitumor effect of PS-K, a Coriolus versicolor preparation, was analyzed on the growth of tumor and the immune reaction in mice. It was shown that PS-K applied in a single dose, as well as repeatedly, systemically (per os or intraperitoneal) has no significant effect on the growth of tumor induced by methylcholantrene (Mch-13). On the other hand, PS-K has a strong antitumor effect on the Ehrilich ascites carcinoma (EAC), so that it can cause regression of already established tumor in about 50% of animals. Animals in which the tumor had regressed were resistant to tumor reinoculation. The inhibitory effect of PS-K on EAC is most probably based on the stimulated production of cytotoxic anti-EAC antibodies. PS-K has a markedly synergistic antitumor effect with cyclophosphamide (CY). Simultaneous application of PS-K and CY causes complete regression of already established methylcholantrene-induced tumor in about 40% of treated animals. In addition, PS-K decreases mortality and/ or prolongs the survival time of animals treated with a lethal dose of CY. PS-K does not prevent CY -toxicity on hematopoietic stem cells, so that the mechanism of its protective effect is not jet clear. In normal animals, intraperitoneal and peroral application of PS-K induces the increase of the mass and cellularity of the spleen, as well as the total number of leukocytes in the blood (mainly mononuclear cells). PS-K increased the mass of the mesenterial lymph node whi1e it decreased the mass of the thymus (especially when administrated i.p.). Peroral application decreased the mass of axillary lymph nodes, while i. p. application slightly increased it.

tumor growth inhibition; PS-K; cyclophosphamide

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