Wilson John T, Postma Almar, Keller Salka, Convertine Anthony J, Moad Graeme, Rizzardo Ezio, Meagher Laurence, Chiefari John, Stayton Patrick S
Department of Bioengineering, University of Washington, Box 355061, Seattle, Washington, 98195, USA.
AAPS J. 2015 Mar;17(2):358-69. doi: 10.1208/s12248-014-9697-1. Epub 2014 Dec 12.
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.
与基于生物体的疫苗相比，基于蛋白质的疫苗具有许多重要优势，但通常引发较差的CD8(+) T细胞反应。我们之前已经证明，pH响应性、溶酶体溶解聚合物可以增强蛋白质抗原向主要组织相容性复合体I类（MHC-I）抗原呈递途径的递送，从而在免疫后增强CD8(+) T细胞反应。在此，我们描述了一种用于蛋白质抗原递送的新型纳米载体家族，其由结构不同的pH响应性聚合物组装而成。可逆加成-断裂链转移（RAFT）聚合用于合成甲基丙烯酸2-(N,N-二乙氨基)乙酯（DEAEMA）和甲基丙烯酸丁酯（BMA）的线性、超支化和核交联共聚物，随后用与硫醇反应性吡啶二硫化物（PDS）基团共聚的亲水性N,N-二甲基丙烯酰胺（DMA）链段进行链延伸。在水溶液中，聚合物链组装成25 nm的胶束纳米颗粒，并实现了硫醇化蛋白质抗原卵清蛋白的高效且可还原偶联。聚合物在红细胞裂解试验中表现出pH依赖性的膜破坏活性，超支化和交联的聚合物结构在pH≤7.0时比线性双嵌段聚合物表现出显著更高的溶血率。与游离抗原相比，具有超支化和交联聚合物结构的抗原递送增强了体外MHC-I抗原呈递，而线性构建体则没有明显效果。相对于交联结构，超支化系统使MHC-I呈递增加了四到五倍，证明了超支化结构在增强MHC-I呈递方面的卓越能力。这项工作表明，pH响应性、溶酶体溶解聚合物的结构可以对细胞内抗原递送产生显著影响，并为增强基于蛋白质的疫苗的CD8(+) T细胞反应提供了一种有前景的策略。
