beta-Glucan Grafted Microcapsule, a Tool for Studying the Immunomodulatory Effect of Microbial Cell Wall Polysaccharides

摘要

beta-(1,3)-Glucan is one of the antigenic components of the bacterial as well as fungal cell wall. We designed microcapsules (MCs) ligated with beta-(1,3)-glucan, to study its immunomodulatory effect. The MCs were obtained by interfacial polycondensation between diacyl chloride (sebacoyl chloride and terephtaloyl chloride) and diethylenetriamine in organic and aqueous phases, respectively. Planar films were first designed to optimize monomer compositions and to examine the kinetics of film formation. MCs with aqueous fluorescent core were then obtained upon controlled emulsification-polycondensation reactions using optimized monomer compositions and adding fluorescein into the aqueous phase. The selected MC-formulation was grafted with Curdlan, a linear beta-(1,3)glucan from Agrobacterium species or branched beta-(1,3)-glucan isolated from the cell wall of Aspergillus fumigatus. These beta-(1,3)-glucan grafted MCs were phagocytosed by human monocyte-derived macrophages, and stimulated cytokine secretion. Moreover, the blocking of dectin-1, a beta-(1,3)-glucan recognizing receptor, did not completely inhibit the phagocytosis of these beta-(1,3)-glucan grafted MCs, suggesting the involvement of other receptors in the recognition and uptake of beta-(1,3)-glucan. Overall, grafted MCs are a useful tool for the study of the mechanism of phagocytosis and immunomodulatory effect of the microbial polysaccharides.