Evaluation of immuno-stimulatory property of PLGA/PBAE microparticles

Success of vaccine formulation depends on its immunogenicity. Traditional vaccines using whole killed pathogen or attenuated pathogen are intrinsically immunogenic, whereas immunogenicity of DNA vaccines relies solely on their delivery system. Synthetic delivery systems like polymeric particles are safe and effective in delivery of DNA but often are less immunogenic. Recently, poly beta amino esters (PBAE polymers) were studied for their use as vaccine delivery system, but their immunogenic potential is not much explored. In this study, the immune stimulatory efficiency of the microparticles made of PBAE and PLGA at different ratio was evaluated by two in vitro assays, viz., T cell rosette assay and phagocytic assay. A dose dependent increase in immune stimulation was observed with all the formulations tested. Additionally, number of T-cell rosettes and phagocytosis was found to be directly proportional to PBAE content. This clearly indicated the role of PBAE polymer in immune stimulation. Further in vivo studies could establish the adjuvancy role of these polymers.