An antitumor component of laetiporus sulphureus and its immunostimulating activity

A protein-polysaccharide fraction was prepared from the carpophores of Laetiporus sulphureus. This fraction suppressed growth of sarcoma 180 in A-strain mice when administered i. p. To investigate the mechanism of antitumor action of this fraction, plaque assay was conducted by administrating i. p. to the mise at a dose level of 50mg/kg for five days. Ten days later, the mice were immunized with 1 * 10$^{7}$ sheep red blooc cells. The number of hemolytic plaque forming cells was significantly greater than that of the control mice. Three monosaccharides and fifteen amino acids were identified in the protein-polysaccharide fraction.