Intensification of antitumor-immunity by protein-bound polysaccharide, EA6, derived from Flammulina velutipes (Curt. ex Fr.) Sing. combined with murine leukemia L1210 vaccine in animal experiments.

The antitumor effect of protein-bound polysaccharide, EA6, derived from fruit bodies of Flammulina velutipes (Curt. ex Fr.) Sing., when combined with a vaccine treatment was studied by the challenge test in BDF1 mice and L1210 murine leukemia system. Intensification of the antitumor effect of EA6 was dependent on doses, timing, and frequency of intraperitoneal administration of the material to the immunization by concanavalin A and/or glutaraldehyde treated L1210 vaccine. Administration of EA6 prior to the injection of the vaccine, or repeated injection of more than 4 times did not increase the life span of the animals. But when EA6 was given (40 mg/kg) after the injection of the vaccine, marked prolongation of the life span (ILS of 223%) was observed against challenging of 1 x 10(2) cells of L1210. Combined treatment of EA6 with vaccine exhibited prolonged ILS in the mice challenged with 1 x 10(3) cells of L1210. The specific immunity for L1210 induced by the vaccine was not affected by EA6.