Effect of protein-bound polysaccharide preparation, PS-K, on the immune response of mice to sheep red blood cells.

The protein-bound polysaccharide preparation, PS-K, was found to potentiate the production of hemolytic plaque-forming cells of spleen and serum hemagglutinin in C57BL/6 mice, when they were immunized with a low dose of sheep red blood cells. PS-K was administered intraperitoneally at a dose of 150 mg/kg daily for 5 days. Ten days later, the mice were immunized with either 4 X 10(8) or 1 X 10(7) sheep red blood cells. Both the number of plaque-forming cells in their spleen and the amount of serum hemagglutinin were significantly higher in the PS-K treated mice when 1 X10(7) sheep red blood cells were used as an immunizing dose.