title: Enhancement of MHC-I antigen presentation via architectural control of pH-responsive, endosomolytic polymer nanoparticles.
abstract: Protein-based vaccines offer a number of important advantages over organism-based vaccines but generally elicit poor CD8(+) T cell responses. We have previously demonstrated that pH-responsive, endosomolytic polymers can enhance protein antigen delivery to major histocompatibility complex class I (MHC-I) antigen presentation pathways thereby augmenting CD8(+) T cell responses following immunization. Here, we describe a new family of nanocarriers for protein antigen delivery assembled using architecturally distinct pH-responsive polymers. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize linear, hyperbranched, and core-crosslinked copolymers of 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA) and butyl methacrylate (BMA) that were subsequently chain extended with a hydrophilic N,N-dimethylacrylamide (DMA) segment copolymerized with thiol-reactive pyridyl disulfide (PDS) groups. In aqueous solution, polymer chains assembled into 25 nm micellar nanoparticles and enabled efficient and reducible conjugation of a thiolated protein antigen, ovalbumin. Polymers demonstrated pH-dependent membrane-destabilizing activity in an erythrocyte lysis assay, with the hyperbranched and cross-linked polymer architectures exhibiting significantly higher hemolysis at pH ≤ 7.0 than the linear diblock. Antigen delivery with the hyperbranched and cross-linked polymer architecture enhanced in vitro MHC-I antigen presentation relative to free antigen, whereas the linear construct did not have a discernible effect. The hyperbranched system elicited a four- to fivefold increase in MHC-I presentation relative to the cross-linked architecture, demonstrating the superior capacity of the hyperbranched architecture in enhancing MHC-I presentation. This work demonstrates that the architecture of pH-responsive, endosomolytic polymers can have dramatic effects on intracellular antigen delivery, and offers a promising strategy for enhancing CD8(+) T cell responses to protein-based vaccines.
authors.affiliation: Department of Bioengineering, University of Washington, Box 355061, Seattle, Washington, 98195, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Wilson
authors.forename: Almar
authors.initials: A
authors.lastname: Postma
authors.forename: Salka
authors.initials: S
authors.lastname: Keller
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Convertine
authors.forename: Graeme
authors.initials: G
authors.lastname: Moad
authors.forename: Ezio
authors.initials: E
authors.lastname: Rizzardo
authors.forename: Laurence
authors.initials: L
authors.lastname: Meagher
authors.forename: John
authors.initials: J
authors.lastname: Chiefari
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Stayton
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003432:Cross-Linking Reagents / Q000737:chemistry; D011992:Endosomes / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051379:Mice; D008823:Micelles; D053758:Nanoparticles; D010047:Ovalbumin / Q000276:immunology; D011108:Polymers / Q000737:chemistry*; D014612:Vaccines / Q000276:immunology*
chemical_list: D000178:Acrylamides; D003432:Cross-Linking Reagents; D015395:Histocompatibility Antigens Class I; D008823:Micelles; D011108:Polymers; D014612:Vaccines; D010047:Ovalbumin; C099046:N,N-dimethylacrylamide