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Competitive action of a biological response modifier, PSK, on a humoral immunosuppressive factor produced in
K Matsunaga1, I Morita, H Iijima
1Biomedical Research Laboratories, Kureha Chemical Industries Co., Ltd., Tokyo, Japan.
Abstract:
We investigated the effect of PSK, a protein-bound polysaccharide obtained from the basidiomycetes Coriolus versicolor, on an immunosuppressive factor produced in tumor-bearing animals. Oral administration of PSK suppressed the growth of the tumor in C3H/He mice bearing X5563 plasmacytoma or MH134 hepatoma, but affected mice bearing MM102 mammary tumor little. PSK prevented the reduction in splenic lymphocyte blastogenesis caused by phytohemagglutinin that occurs in mice bearing X5563 tumors or MH134 hepatoma. The lymphocyte blastogenesis affected little by tumor or PSK in mice bearing MM102 tumors. The effect of sera on the blastogenesis of lymphocytes caused by phytohemagglutinin was different with different tumors in the C3H/He mice. Serum of mice bearing X5563 tumors inhibited blastogenesis, but serum of mice bearing MH134 hepatoma or MM102 tumors promoted it. The sera of mice bearing MH134 hepatoma contained both inhibitory and promotive factors; those of mice bearing X5563 tumors contained an inhibitory factor, and those of mice bearing MM102 tumors contained a promotive factor. The oral administration of PSK reduced the inhibition caused by the sera of mice bearing X5563 tumors. The promotive activity of sera from mice bearing MH134 hepatoma was augmented by PSK; that of sera in mice bearing MM102 tumors was not affected by PSK. Living Bacillus Calmette-Guérin did not have such effects in any of these mice. Serum immunosuppressive activity was also reduced by PSK in various tumor lines of rodents. These results suggest that PSK acts by reducing the activity of immunosuppressive factors produced in tumor-bearing hosts.
Insights
PSK, a compound from Coriolus versicolor, was studied for its effects on tumor growth and immune suppression in mice. PSK demonstrated potential in reducing tumor-related immunosuppressive factors, suggesting a therapeutic benefit.
Area of Science:
- Immunology
- Pharmacology
- Oncology
Background:
- Tumor-bearing hosts often exhibit suppressed immune responses.
- Certain tumors produce immunosuppressive factors that hinder anti-tumor immunity.
- PSK (polysaccharide-K) is a protein-bound polysaccharide from Coriolus versicolor with known biological activities.
Purpose of the Study:
- To investigate the effect of PSK on immunosuppressive factors in tumor-bearing animals.
- To determine if PSK can modulate the host's immune response against tumors.
- To assess the impact of PSK on lymphocyte blastogenesis in the presence of different tumor types.
Main Methods:
- Oral administration of PSK to mice bearing X5563 plasmacytoma, MH134 hepatoma, or MM102 mammary tumor.
- Assessment of tumor growth inhibition.
- Measurement of splenic lymphocyte blastogenesis induced by phytohemagglutinin.
- Analysis of serum immunosuppressive and promotive activities on lymphocyte blastogenesis.
Main Results:
- PSK suppressed tumor growth in mice with X5563 plasmacytoma and MH134 hepatoma, but not MM102 mammary tumor.
- PSK prevented the reduction in lymphocyte blastogenesis in mice bearing X5563 or MH134 tumors.
- PSK reduced serum immunosuppressive activity in X5563 tumor-bearing mice and augmented promotive activity in MH134 tumor-bearing mice.
Conclusions:
- PSK exhibits immunomodulatory effects by reducing the activity of immunosuppressive factors in tumor-bearing hosts.
- PSK demonstrates potential as an adjuvant therapy to enhance anti-tumor immunity.
- The efficacy of PSK may vary depending on the tumor type and its associated immune-suppressive mechanisms.