Antitumor Activity of P-MSY, a Protein from Bovine Parotid Glands, and Some Observations relating to the Activity

Abstract

When P-MSY, a component of bovine parotid glands, was injected at a dose of 1μg/head/d, daily for 10 d starting 24 h after the transplantation of ascites Ehrlich carcinoma cells, the solid tumor formed was rejected in 6 of 10 mice, and the tumor inhibition rate was 86.4%. Subcutaneous injection of 1μg/head/d, daily for 7 d before transplantation of sarcoma-180 cells resulted in prolongation of the life span of ascites tumor-bearing mice, the mean survival period being 19.4 d against 14.1 d in the control ; T/C was 138%. Such a life-prolonging effect was not observed when P-MSY was administered after the transplantation of the tumor. Electrophoresis of the serum from mice in which the tumor had been rejected after the administration of P-MSY revealed increased quantities of some protein components. By examinations of delayed-type skin reaction, P-MSY was found to hinder significantly the lowering of cellular immunity in tumor-bearing mice.