Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA.
Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA.
Acta Biomater. 2015 Mar;14:104-14. doi: 10.1016/j.actbio.2014.11.050. Epub 2014 Dec 4.
We have synthesized thermogelling cationic amphiphilic pentablock copolymers that have the potential to act as injectable vaccine carriers and adjuvants that can simultaneously provide sustained delivery and enhance the immunogenicity of released antigen. While these pentablock copolymers have shown efficacy in DNA delivery in past studies, the ability to deliver both DNA and protein for subunit vaccines using the same polymeric carrier can provide greater flexibility and efficacy. We demonstrate the ability of these pentablock copolymers, and the parent triblock Pluronic copolymers to slowly release structurally intact and antigenically stable protein antigens in vitro, create an antigen depot through long-term injection-site persistence and enhance the in vivo immune response to these antigens. We show release of the model protein antigen ovalbumin in vitro from the thermogelling block copolymers with the primary, secondary and tertiary structures of the released protein unchanged compared to the native protein, and its antigenicity preserved upon release. The block copolymers form a gel at physiological temperatures that serves as an antigenic depot and persists in vivo at the site of injection for over 50days. The pentablock copolymers show a significant fivefold enhancement in the immune response compared to soluble protein alone, even 6weeks after the administration, based on measurement of antibody titers. These results demonstrate the potential of these block copolymers hydrogels to persist for several weeks and sustain the release of antigen with minimal effects on protein stability and antigenicity; and their ability to be used simultaneously as a sustained delivery device as well as a subunit vaccine adjuvant platform.
我们合成了具有热敏性的阳离子两亲性五嵌段共聚物，有望成为可注射疫苗载体和佐剂，同时能够提供持续的药物递送并增强释放抗原的免疫原性。虽然这些五嵌段共聚物在过去的研究中已经显示出在 DNA 递送上的功效，但能够使用相同的聚合物载体递送 DNA 和蛋白质用于亚单位疫苗，能够提供更大的灵活性和功效。我们证明了这些五嵌段共聚物以及母体三嵌段普朗尼克共聚物能够在体外缓慢释放结构完整且具有免疫原性稳定的蛋白质抗原，通过长期注射部位的持续存在形成抗原库，并增强这些抗原在体内的免疫反应。我们展示了模型蛋白抗原卵清蛋白从热敏性嵌段共聚物中的体外释放，与天然蛋白相比，释放的蛋白的一级、二级和三级结构没有改变，并且其抗原性在释放后得以保留。这些嵌段共聚物在生理温度下形成凝胶，作为抗原库，并在体内注射部位持续存在超过 50 天。与单独的可溶性蛋白相比，五嵌段共聚物使免疫反应显著增强了五倍，即使在给药 6 周后，基于抗体滴度的测量也是如此。这些结果表明，这些嵌段共聚物水凝胶具有持续数周的潜力，并能够持续释放抗原，对蛋白质稳定性和抗原性的影响最小；并且它们能够同时用作持续释放装置以及亚单位疫苗佐剂平台。
