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Stimulation of tumor necrosis factor-induced human myelogenous leukemic cell differentiation by high molecular weight
1First Department of Biochemistry, School of Medicine, Showa University, Tokyo, Japan.
Abstract:
The mouse macrophage-like cell line, J774.1, spontaneously released differentiation-inducing factor(s). When these cells were treated with a protein-bound polysaccharide, PSK, significantly higher amounts of differentiation-inducing activity were accumulated in the culture supernatant. PSK directly stimulated human myelogenous leukemic cell differentiation induced by J774.1 conditioned medium or by tumor necrosis factor. Among four subfractions of PSK, only the highest molecular weight fraction (MW greater than 200 kD) exerted such a stimulating effect.
Insights
Protein-bound polysaccharide (PSK) enhances macrophage differentiation. Specifically, a high molecular weight fraction of PSK significantly boosted the differentiation of leukemic cells induced by J774.1 conditioned medium or tumor necrosis factor.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- The J774.1 mouse macrophage cell line spontaneously releases differentiation-inducing factors.
- Tumor necrosis factor (TNF) is known to induce myeloid leukemic cell differentiation.
Purpose of the Study:
- To investigate the effect of protein-bound polysaccharide (PSK) on macrophage differentiation.
- To determine if PSK can enhance leukemic cell differentiation induced by J774.1 conditioned medium or TNF.
Main Methods:
- Culturing J774.1 mouse macrophage-like cells.
- Treating cells with protein-bound polysaccharide (PSK) and its subfractions.
- Measuring differentiation-inducing activity in culture supernatants.
- Assessing the direct stimulation of human myelogenous leukemic cell differentiation.
Main Results:
- PSK treatment significantly increased differentiation-inducing activity in J774.1 cell culture supernatants.
- PSK directly stimulated human myelogenous leukemic cell differentiation.
- Only the highest molecular weight fraction (MW > 200 kD) of PSK exhibited this stimulating effect.
Conclusions:
- Protein-bound polysaccharide (PSK) potentiates macrophage differentiation-inducing activity.
- A high molecular weight component of PSK is responsible for enhancing leukemic cell differentiation.