Influence of structural features on immunostimulating activity of glucans extracted from Agaricus blazei mushroom

Abstract

High molecular weight b-D-glucans derived from Basidiomycetes cell walls are able to specifically activate cellular and humoral components of the host immune system. The aim of this paper was to examine immunomodulating activity of native, chemically and enzimatically modified glucans from Agaricus blazei mushroom and to determine which structural features are of primary importance for their stimulation referring to humane immune cells. The immunomodulating activities were tested in vitro, by stimulation of peripheral blood mononuclear cells (PBMCs) and measuring of interferon-gamma (IFN-g) production by enzyme linked immunosorbent assay (ELISA). Measurements of immunomodulatory capacity of Agaricus blazei native glucans showed their expressive immunostimulating effect on activated PBMCs and synthesis of IFN-g. The results obtained after the stimulation of cells with 1M H2SO4 and 1M NaOH, the treated glucans showed that primary structure is of more importance than the tertiary structure of the triple helix for their immunostimulating activity and synthesis of IFN-g. Glucans of lower molecular weight obtained after acid hydrolysis appeared as effective immunostimulators of PBMC's. The results obtained after the incubation of cells with 1,6 b-glucanase modified glucans suggest that b-(1,6) binding of glucose monomers probably has no importance for the production of imunostimulating effects, in vitro. This confirmed that b-(1,3) bonds are the primary determinants of immunomodulatory activities and stimulation of IFN-g synthesis.

Keywords

• Agaricus blazei
• b-D-glucans
• IFN-g
• immunostimulating activity
• PBMC's