Increased efficiency of Lewis lung carcinoma chemotherapy with a macrophage stimulator--yeast carboxymethyl glucan

The efficiency of chemotherapy of Lewis lung carcinoma with cyclophosphamide was affected by administration of the water-soluble yeast polysaccharide derivative--carboxymethylated (1 --> 3)-beta-D-glucan (CMG)-a well-known macrophage stimulator. It was found that while cyclophosphamide showed 57% growth inhibition of the intramuscular tumor implants in comparison with the control group, its combined administration with CMG led to 75-90% inhibition. Similarly, increased inhibition of occurrence of lung metastases (up to 92-94%) was observed using the combined application of the two compounds. The stimulatory effect of CMG is not associated with the changed cellularity of peripheral blood, but is rather due to the obviously increased concentration of the intracellular inhibitor of cysteine proteases-stefin A and cystatin C in tumor tissue.