Résumé
Receptors of plant polysaccharides and their signaling pathways have become a hotspot of polysaccharide activity research. As immunomodulators, polysaccharides have attracted much attention due to their immunomodulatory effects mediated by cell surface receptors. Polysaccharide receptors mainly include C-type lectin receptor family, mannose receptor family (MR), Toll-like receptor family (TLR), complement receptor 3 (CR3), scavenger receptor and so on, and these receptors play an important role in the recognition between polysaccharides and cells, which is closely related to polysaccharides activities, such as enhancing cellular immune function, regulating the secretion of cytokines, having immunomodulatory and antineoplastic effects. In this paper, polysaccharide receptors types, biological functions and signal transduction pathways are reviewed, it will be helpful to elucidate the pharmacological activity mechanism of plant polysaccharides and provide theoretical reference for the comprehensive development of polysaccharide drugs.
Résumé
Macrophage-inducible C-type lectin (mincle receptor) is a novel unclassical C-type lectin receptor member,which is mainly expressed on the surface of antigen presenting cells.Under the stimulation of fungus,mycobacterium tuberculosis and necrotic cells,mincle receptor plays anatural immune effect in host body by binding to relevant ligand and activate nuclear factor-κB (NF-κB) signaling pathway,which promotes the expression of many inflammatory factors.Up to now,the laboratory and clinical studies on mincle receptor and infected diseases is being a hot topic.However,these study is lack in ophthalmology.Understanding the association of mincle receptor to infected eye diseases will offer a new approach to the immunotherapy.The basic concept,acting mechanism,its relationship to inflammatory eye diseases and outlook in ophthalmology of mincle receptor were reviewed in this paper.
Résumé
Dectin-1, which specifically recognizes beta-glucan of fungal cell walls, is a non-Toll-like receptor (TLR) pattern recognition receptor and a representative of C-type lectin receptors (CLRs). The importance of Dectin-1 in innate immune cells, such as dendritic cells and macrophages, has previously been well studied. However, the function of Dectin-1 in B cells is very poorly understood. To determine the role of Dectin-1 in B cell activation, we first investigated whether mouse B cells express Dectin-1 and then assessed the effect of Dectin-1 stimulation on B cell proliferation and antibody production. Mouse B cells express mRNAs encoding CLRs, including Dectin-1, and surface Dectin-1 was expressed in B cells of C57BL/6 rather than BALB/c strain. Dectin-1 agonists, heat-killed Candida albicans (HKCA) and heat-killed Saccharomyces cerevisiae (HKSC), alone induced B cell proliferation but not antibody production. Interestingly, HKSC, HKCA, and depleted zymosan (a selective Dectin-1 agonist) selectively enhanced LPS-driven IgG1 production. Taken together, these results suggest that, during fungal infection, beta-glucan-stimulated Dectin-1 may cooperate with TLR4 to specifically enhance IgG1 production by mouse B cells.