Potential of the β-glucans to enhance innate resistance to biological agents

Abstract

The use of numerous mushroom species in traditional medicine has been widely documented, with their observed immunomodulatory effects now attributed, in part, to bioactive components called beta-glucans. The beta-glucans are of particular interest since they are naturally occurring polymers of glucose, are orally active when taken as food supplements and have a long track record of safe use. Due to their immunomodulatory properties, purified beta-glucans have been used clinically as part of a combination therapy for a variety of cancers and their potential anti-infective properties have received attention. This review relates the structure of beta-glucans to their function, with a particular focus on their documented immunomodulatory effects and the mechanisms by which they affect inter- and intracellular function, resulting in potential antimicrobial benefits. Overall, the benefits of dietary supplementation with beta-glucans in order to enhance innate resistance to biological agents are evaluated.

An Overview of the Immunological Defenses in Fish Skin

“…This is a very new area of interest with a great applicated potential in aquaculture systems. For many fish species, the immune modulation activity of beta-glucans has been reported [315], and recent preliminary research data indicates that beta-glucan promotes an antimicrobial response [316]. Furthermore, beta-glucans can potentially affect mucin structure and/or function as they interact with innate signalling pathways in mucus producing cells.…”

Immune modulating effects of β-glucan

“…As a result of their ability to enhance immune function b-glucans have been shown to elicit a wide range of antiinfective activity including enhanced host resistance to various bacterial, viral, protozoan, and fungal diseases [29]. The majority of evidence comes from animal data with relatively few human studies available.…”

Immunomodulatory effects of mushroom β-glucans

“…A variety of PRRs are responsible for β-glucan recognition; for instance Dectin-1, CR3, lactosylceramide and scavenger receptors (SRs) (Brown and Gordon, 2001;Ujita et al, 2009). These receptors are positioned on specific cell surface areas of monocytes, macrophages, dendritic cells (DCs), neutrophils, eosinophils and NK cells, and on some non-immune cells such as enterocytes, alveolar cells and fibroblasts (Thompson et al, 2010).…”

“…Complement receptor 3 (CR3) is an integrin dimer consisting of CD11b noncovalently associated with CD18 (Thornton et al, 1996;Thompson et al, 2010). It is expressed on neutrophils, NK cells, DC, and T and B lymphocyte subsets, and is less strongly expressed on macrophages (Ross, 2000).…”

“…β-glucans induce NFκB gene expression via Dectin-1 in association with TLR-2 and -4 in a MyD88-dependent signalling cascade (Thompson et al, 2010). Up-regulation of the NFκB gene is considered significant as an important regulator of cellular activation, cell cycle progression, cell survival, cell adhesion, invasion and inflammatory responses (Ravi and Bedi, 2004).…”