Abstract

Lyophyllan A was isolated as an antitumor component from Lyophyllum decstes. To elucidate mechanisms of its antitumor activity, its effects on immune response were examined. Lyophyllan A restored the suppressed delayed-type hypersensitivity reaction in tumor-bearing mice up to 85.7% of the normal level. Also lyophyllan A enhanced in vivo generation of cytotoxic T-lymphocytes. When effects of lyophyllan A on natural killer cells that are one of the important nonspecific evvector cells were examined, it augmented natural killer activity in the spleen cells of mice. These results showed that lyophyllan A is an immunopotentiator.