β-(1,3)-Glucan is one of the antigenic components of the bacterial as well as the fungal cell wall. We designed microcapsules (MCs) ligated with β-(1,3)-glucan, to study its immunomodulatory effect. The MCs were obtained by interfacial polycondensation between diacylchloride (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 fluorescene into aqueous phase. The selected MC-formulation was grafted with curdlan, a linear β-(1,3)-glucan from Agrobacterium species or branched β-(1,3)-glucan isolated from the cell wall of Aspergillus fumigatus. These β-(1,3)-glucan grafted MCs were phagocytosed by human monocyte-derived macrophages, and stimulated cytokine secretion. Moreover, the blocking of dectin-1, a β-(1,3)-glucan recognizing receptor, did not completely inhibit the phagocytosis of these β-(1,3)-glucan grafted MCs, suggesting the involvement of other receptors in the recognition and uptake of β-(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.
This study was supported by the Centre Franco-Indien pour la Promotion de la Recherche avancée and Agence nationale de la recherche-Deutsche Forschungsgemeinschaft grants, the Institut Universitaire de France, La région Ile de France, BPI France and benefited from the facilities of MIMA2 MEB-GABI, INRA, Agroparistech, 78352 Jouy-en-Josas, France.
CEFIPRA (Centre Franco-Indien pour la Promotion de la Recherche avancée; Grant No. 5403-1, Pathogenic Aspergillus) to JPL and VA, and Agence nationale de la recherche and Deutsche Forschungsgemeinschaft (ANR-DFG bilateral grant, AfuINTERACT) to JPL.