Structure-Functional Activity Relationship of β-Glucans From the Perspective of Immunomodulation: A Mini-Review

Abstract

β-Glucans are a heterogeneous group of glucose polymers with a common structure comprising a main chain of β-(1,3) and/or β-(1,4)-glucopyranosyl units, along with side chains with various branches and lengths. β-Glucans initiate immune responses via immune cells, which become activated by the binding of the polymer to specific receptors. However, β-glucans from different sources also differ in their structure, conformation, physical properties, binding affinity to receptors, and thus biological functions. The mechanisms behind this are not fully understood. This mini-review provides a comprehensive and up-to-date commentary on the relationship between β-glucans' structure and function in relation to their use for immunomodulation.

Curdlan, zymosan and a yeast-derived β-glucan reshape tumor-associated macrophages into producers of inflammatory chemo-attractants

“…When taken current viewpoints together, both soluble and insoluble β-glucan fractions are capable of supporting immune responses, yet we argue that the β-glucan activity towards the production of chemo-attractants and potentially towards a cellular immune response is expected to be linked to insoluble β-glucans. Besides solubility, we cannot exclude that other physicochemical properties of β-glucans also contribute to the observed effects, such as degree of branching and higher order structures [42]. The same holds true for differential expression levels of PRRs upon exposure to β-glucans, as we have previously observed for dietary fibers and again in our microarray data ( [29] and data not shown).…”

β-Glucan-Induced Trained Immunity in Dogs

“…These results can be linked to the analysis of canine Dectin-1 conformation, the cell-surface receptor of β-glucan. These differences in subsequent biological activities of β-glucans could be attributed to dissimilarities in their capacity of binding to the Dectin-1 given its conformation ( 40 ). As mentioned earlier, Dectin-1 structures are highly conserved among studied species.…”

“…The general implications of branching, molecular weight and conformation of β-glucan is still unclear for the most part although linear chains or poorly branched molecules seem to display the highest biological activity throughout all models ( 40 ). The differences between species' isoforms of Dectin-1, the preferential receptor alone or associated to co-receptors for β-glucans, could partly explain this issue.…”

Pomegranate Peel as Suitable Source of High-Added Value Bioactives: Tailored Functionalized Meat Products

“…PP has also been described to be a new source of dietary fiber, specifically β-glucans [ 38 ]. β-glucan is a heterogeneous non-starch polysaccharide constituted of β- d -glucose units linked by β-(1–4) and β-(1–3) glycosidic bonds [ 39 ]. We have only found one study that refers to β-glucans from PP [ 38 ].…”