Dual-Responsive Glycopolymers for Intracellular Codelivery of Antigen and Lipophilic Adjuvants

Abstract

Traditional approaches to vaccines use whole organisms to trigger an immune response, but they do not typically generate robust cellular-mediated immunity and have various safety risks. Subunit vaccines composed of proteins and/or peptides represent an attractive and safe alternative to whole organism vaccines, but they are poorly immunogenic. Though there are biological reasons for the poor immunogenicity of proteins and peptides, one other key to their relative lack of immunogenicity could be attributed to the poor pharmacokinetic properties of exogenously delivered proteins and peptides. For instance, peptides often aggregate at the site of injection and are not stable in biological fluids, proteins and peptides are rapidly cleared from circulation, and both have poor cellular internalization and endosomal escape. Herein, we developed a delivery system to address the lack of protein immunogenicity by overcoming delivery barriers as well as codelivering immune-stimulating adjuvants. The glycopolymeric nanoparticles (glycoNPs) are composed of a dual-stimuli-responsive block glycopolymer, poly[2-(diisopropylamino)ethyl methacrylate]-b-poly[(pyridyl disulfide ethyl methacrylate)-co-(methacrylamidoglucopyranose)] (p[DPAb-(PDSMA-co-MAG)]). This polymer facilitates protein conjugation and cytosolic release, the pH-responsive release of lipophilic adjuvants, and pH-dependent membrane disruption to ensure cytosolic delivery of antigens. We synthesized p[DPA-b-(PDSMA-co-MAG)] by reversible addition−fragmentation chain transfer (RAFT) polymerization, followed by the formation and physicochemical characterization of glycoNPs using the p[DPA-b-(PDSMA-co-MAG)] building blocks. These glycoNPs conjugated the model antigen ovalbumin (OVA) and released OVA in response to elevated glutathione levels. Moreover, the glycoNPs displayed pH-dependent drug release of the model hydrophobic drug Nile Red while also exhibiting pH-responsive endosomolytic behavior as indicated by a red blood cell hemolysis assay. GlycoNPs coloaded with OVA and the toll-like receptor 7/8 (TLR-7/8) agonist Resiquimod (R848) activated DC 2.4 dendritic cells (DCs) significantly more than free OVA and R848 and led to robust antigen presentation of the OVA epitope SIINFEKL on major histocompatibility complex I (MHC-I). In sum, the dual-stimuliresponsive glycopolymer introduced here overcomes major protein and peptide delivery barriers and could vastly improve the immunogenicity of protein-based vaccines.

Reactive oxygen species/glutathione dual sensitive nanoparticles with encapsulation of miR155 and curcumin for synergized cancer immunotherapy

“…The Gu, Hb and DSMA monomers were synthesized according to the literature [ 29 , 30 ]. To synthesize the macroinitiator mPEG-CTA, CPADB, which possessed a carboxyl terminus, was connected to mPEG-OH through an esterification reaction.…”

Discovery of Kinetic Trapping of Poloxamers inside Liposomes via Thermal Treatment

“…Many amphiphilic polymers, such as PEO–PPO, poly­( N -isopropyl­acrylamide), and glycopolymers, contain moieties that form hydrogen bonds with water. Because of the entropic cost of constraining translation of water molecules bonded to the polymer, as temperature increases the hydrogen-bonded water shell dehydrates, making aqueous solutions of these materials thermoresponsive, lower-critical-solution-temperature systems. − One consequence of this effect is the decreasing critical micelle concentration (CMC) with increasing temperature . Poloxamers are nonionic ABPs with PEO–PPO–PEO triblock architecture that are commercially available over a range of molecular weights and compositions and are biocompatible. , Poloxamer binding to phospholipid bilayers is endothermic, driven by entropically dominated hydrophobic forces. , Because the hydrophobic effect and the hydrogen-bonded water shell of PEO and PPO are sensitive to temperature, it is important to understand how temperature and thermal history affect poloxamer–lipid bilayer interactions.…”