(232g) Engineering the Release of Protein Antigens by pH-Responsive Blend Polymer Particles

Synthetic vaccines can provide more precise control of the quality and quantity of immune responses. In order to generate a broad spectrum of immune responses against a given infections, multiple antigens are required. Different antigens exhibit different size, charge and solubility, all of which affect their release from polymeric delivery systems. The release of antigens in extracellular space and intracellular compartments is critical for obtaining desired immune responses. The current study focuses on modulating the release of proteins with varied isoelectric points. pH-responsive blend polymer particles made from three polymers, poly(lactic-co-glycolic acid) (PLGA) and two random pH-sensitive copolymer, have been developed for the delivery of antigens. Three model proteins with the same sizes and different isoelectric points were effectively incorporated into these particles. By tuning the composition of the polymer blend, we were able to modulate the release of the three proteins at different pH environments. Our results demonstrate a promising approach to control the release of multiple antigens and thus corresponding immune responses.