PLGA microspheres phagocytosis by pig alveolar macrophages: influence of poly(vinyl alcohol) concentration, nature of loaded-protein and copolymer nature.

The study aimed to investigate on a pig alveolar macrophage culture model the influence of: (1) poly(D,L-lactide-co-glycolide) characteristics, (2) the residual poly(vinyl alcohol) (PVA) and (3) the nature of encapsulated proteins, immunoglobulin Y (IgY) or bovine serum albumin, on the microspheres phagocytosis efficiency. The phagocytosis evaluation was performed by flow cytometry and has allowed a screening of microspheres formulations. The hydrophilicity of microspheres resulting from the nature of the polymer and/ or from the residual hydrophilic surface agent (PVA) led to a decrease of phagocytosis intensity. The phagocytosis results of IgY-loaded microspheres strongly suggested that the phagocytosis was increased when the phagocytic cell possessed a receptor for this protein on its surface.