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Updated: Aug 30, 2026
Experimental Melanoma Immunotherapy Model Using Tumor Vaccination with a Hematopoietic Cytokine
Published on: February 24, 2023
[Activation of antitumor immunity by intratumor injection of biological preparations]
1Division of Immunology, Miyagi Cancer Center Research Institute.
Abstract:
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.
Insights
Biological response modifiers (BRMs) like PSK and Agaricus preparation showed significant antitumor effects against primary and metastatic tumors in mice. These BRMs activate macrophages, demonstrating potential in cancer immunotherapy.
Area of Science:
- Immunology
- Pharmacology
- Oncology
Background:
- Biological response modifiers (BRMs) can modulate the immune system to fight cancer.
- Macrophage activation is a key mechanism in the anti-tumor immunological cascade.
- Understanding BRM efficacy is crucial for developing novel cancer therapies.
Purpose of the Study:
- To evaluate the antitumor effects of various BRMs in a mouse model.
- To investigate the role of BRMs in preventing tumor metastasis.
- To determine the correlation between BRM administration and macrophage activation.
Main Methods:
- Utilized a double grafted tumor system in an experimental mouse model.
- Administered and analyzed the effects of PSK, Lentinan, Agaricus preparation, and Tricholoma matsutake fractions (M1 and M2).
- Assessed tumor growth, metastasis inhibition, and induction of immunosuppressive acidic protein (IAP) as a marker of macrophage activation.
Main Results:
- PSK demonstrated complete cure of primary and metastatic tumors.
- Agaricus preparation and the M2 fraction of Matsutake inhibited tumor growth and metastasis.
- Lentinan and the M1 fraction of Matsutake showed no significant antitumor or anti-metastatic effects.
- PSK, Agaricus preparation, and M2 fraction induced IAP, indicating macrophage activation.
Conclusions:
- Certain BRMs, including PSK and Agaricus preparation, exhibit potent antitumor and anti-metastatic properties.
- Macrophage activation, evidenced by IAP induction, is a likely mechanism for the observed therapeutic effects.
- The study highlights the differential efficacy of various BRMs, suggesting a need for tailored therapeutic strategies.
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