Preparation and in Vitro Characterization of Carrier Erythrocytes for Vaccine Delivery

Abstract

 Erythrocytes  as the most readily available and abundant cells within the body, have been studied extensively for their potential application as  drug delivery  carriers. In this study, human  erythrocytes have been loaded  by bovine serum albumin (BSA) as  a  model antigen/protein using hypotonic preswelling method for targeted  delivery  of this antigen to antigen-presenting cells (APCs).  A  series of in vitro tests have been carried out to characterize the carrier cells in vitro, including loading parameters, BSA and hemoglobin release kinetics, hematological indices, particle size distribution, SEM analysis, osmotic and turbulence fragility, and osmotic competency. BSA was  loaded  in  erythrocytes with a loaded  amount of 1.98 ± 0.009 mg with antigen release from carrier cells showing  a  zero-order kinetic consistent to that of the cell lysis. The apparent cell sizes, measured using laser scattering, were not significantly different from normal  erythrocytes,  but the real sizes, measured using SEM, and surface topologies were quite different between  loaded  and unloaded cells. The BSA- loaded  cells were remarkably more fragile and less deformable compared to the normal cells. Totally, BSA- loaded erythrocytes  seem to be  a  promising  delivery system  for reticuloendothelial  system  (RES) targeting of the antigens.