Calcium phosphate nanoparticles show an effective activation of the innate immune response in vitro and in vivo after functionalization with flagellin

For subunit vaccines,adjuvants play a key role in shaping the magnitude,persistence and form of targeted antigen-specific immune response.Flagellin is a potent immune activator by bridging innate inflammatory responses and adaptive immunity and an adjuvant candidate for clinical application.Calcium phosphate nanoparticles are efficient carriers for different biomolecules like DNA,RNA,peptides and proteins.Flagellin-functionalized calcium phosphate nanoparticles were prepared and their immunostimuiatory effect on the innate immune system,i.e.the cytokine production,was studied.They induced the production of the proinflammatory cytokines IL-8(Caco-2 cells) and IL-1β(bone marrow-derived macrophages;BMDM) in vitro and IL-6 in vivo after intraperitoneal injection in mice.The immunostimulation was more pronounced than with free flagellin.