Stimulatory Effect of β-glucans on Immune Cells

β-Glucans are naturally occurring polysaccharides that are produced by bacteria, yeast, fungi, and many plants. Although their pharmacological activities, such as immunomodulatory, anti-infective and anti-cancer effects, have been well studied, it is still unclear how β-glucans exert their activities. However, recent studies on the β-glucan receptors shed some light on their mechanism of action. Since β-glucans have large molecular weights, they must bind surface receptors to activate immune cells. In this review, we summarize the immunopharmacological activities and the potential receptors of β-glucans in immune cells.

Keywords

β-glucan; Receptors; Immune cells

CHEMISTRY OF β-GLUCANS

β-Glucans are heterogeneous polysaccharides of glucose polymer, consisting of a backbone of β-(1-3)-linked β-D-glucopyranosyl units with β-(1-6)-linked side chains of varying distribution and length. The activity of β-glucan depends on the molecular structure, size, branching frequency, structural modification, conformation, and solubility. It appears that the most active forms of β-glucans contain β-(1-3)(1-6) linkages (1). The structure of several biologically active β-glucans has been reported. β-Glucan from many mushrooms has a β-(1-3) backbone with shorter β-(1-6) linked branches, while β-glucan from Alcaligenes faecalis contains only β-(1-3)-glucosidic linkages (2). Schizophyllan from Schizophyllum commune and scleroglucan from Sclerotium glucanicum both have a β-(1