Size-Dependent Phagocytic Uptake and Immunogenicity of Gliadin Nanoparticles

The main objective of the present study was to investigate the hemo and immune compatibility of gliadin nanoparticles as a function of particle size. Gliadin nanoparticles of different size were prepared using a modified antisolvent nanoprecipitation method. The hemolytic potential of gliadin nanoparticles was evaluated using in vitro hemolysis assay. Phagocytic uptake of gliadin nanoparticles was studied using rat polymorphonuclear (PMN) leukocytes and murine alveolar peritoneal macrophage (J774) cells. In vivo immunogenicity of gliadin nanoparticles was studied following subcutaneous administration in mice. Gliadin nanoparticles were non-hemolytic irrespective of particle size and hence compatible with blood components. In comparison to positive control zymosan, gliadin nanoparticles with a size greater than 406 ± 11 nm showed higher phagocytic uptake in PMN cells, while the uptake was minimal with smaller nanoparticles (127 ± 8 nm). Similar uptake of gliadin nanoparticles was observed in murine alveolar peritoneal macrophages. Anti-gliadin IgG antibody titers subsequent to primary and secondary immunization of gliadin nanoparticles in mice were in the increasing order of 406 ± 11 nm < 848 ± 20 nm < coarse suspension). On the other hand, gliadin nanoparticles of 127 ± 8 nm in size did not elicit immunogenic response. Phagocytosis and immunogenicity of gliadin nanoparticles are strongly influenced by particle size. The results of this study can provide useful information for rational design of protein-based nanomaterials in drug delivery applications.