Tricholomataceae. We found antitumor component, component, collyban(CB), from the cultured mycelia of this mushroom. CB showed antitumor effect on sarcoma 180(S180) and HeLa cell lines and life prolonging effect on S180 and MM 46 carcinoma in
vivo.
In
this study, we report the immunological effect of CB to elucidate the mechanism of its antitumor activity. CB did not show any direct cytotoxicity on S180, P 388 and Ll210 tumor cell lines except on HeLa cell line. CB increased the number of
murine
peritoneal exudate cells, especially the mature forms of polymorphonuclear leucocytes. By flow cytometric analysis, CB apparently induced the increase of Mac-1+ murine splenic B lymphocytes in the early stage of tumor growth. Moreover, on the
late
stage, it restored the decrased percentages of CD4+ and CD8+ splenic T lymphocytes in the tumor bearing mice to normal levels, indicating that those cytotoxic/helper T lymphocytes were increased by the CB administration. CB increased both the
production
of the acid phosphatase and the release of the superoxide anion from activated macrophages in mice. It showed not only adjuvant effect by increasing the number of the hemolytic plaque forming cells against sheep red blood cells but also
stimulatory
effect in the production of splenic alkaline phosphatase which is an index of the proliferation or activation of the B lymphocytes in the murine spleen cells. In cellular immunity, CB restored the depressed response of delayed type
hypersensitivity
in
the tumor bearing mice to normal level. In nude mice, CB potentiated the cytotoxicity of natural killer cell which is one of important nonspecific effector cells. From these results, CB showed a direct killing effect on HeLa cell line, activated
humoral
and cellular immunological functions and restored the decreased immune response of the tumor bearing host to the normal level. It is therefore concluded that CB acts as an immunomodulator.
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