[Activation of antitumor immunity by intratumor injection of biological preparations]

Division of Immunology, Miyagi Cancer Center Research Institute.

The antitumor effects of biological response modifiers (BRMs) in an experimental mouse model using a double grafted tumor system were analyzed. Some BRMs prevented metastases by utilizing the anti-tumor immunological cascade reactions, which activate macrophages in the body. The following BRMs were analyzed: PSK was a hot water extract of cultured mycelia from Coliolus versicolor and a protein bound beta-glucan. Lentinan was purified from fruit bodies of Lentinus erodes and is a beta-glucan. The agaricus preparation was extracted from fruit bodies of Agaricus blazei and a protein-bound alpha-, beta-glucan. The M2 fraction was extracted from mycelia of Tricholoma matsutake and was a protein bound alpha-glucan. M1 fraction was purified from mycelia of T. matsutake and was an alpha-glucan. PSK cured both primary and metastatic tumors in the double grafted tumor system. Lentinan did not inhibit the growth of either primary or metastatic tumors. Agaricus preparation cured a primary tumor and inhibited the growth of a metastatic tumor. The M2 fraction prepared from Matsutake inhibited the growth of both primary and metastatic tumors. The M1 fraction did not inhibit either primary or metastatic tumors. Immunosuppressive acidic protein (IAP) is produced by activated macrophages. The PSK, Agaricus preparation and M2 fraction of the Matsutake preparation induced IAP but the lentinan and M1 fraction did not.