Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, USA.
Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, PA 15219, USA.
Acta Biomater. 2023 Oct 15;170:453-463. doi: 10.1016/j.actbio.2023.08.048. Epub 2023 Aug 29.
Generation of protective immunity through vaccination arises from the adaptive immune response developed primarily in the lymph nodes drained from the immunization site. Relative to the intramuscular route, subcutaneous administration allows for direct and rapid access to the lymphatics, but accumulation of soluble protein antigens within the lymph nodes is limited. Subunit vaccines also require immune stimulating adjuvants which may not accumulate in the same lymph nodes simultaneously with antigen. Herein we report the use of biotinylated poly (lactic-co-glycolic acid) nanoparticles (bNPs) to enhance delivery of a model protein antigen to the lymphatics. bNPs provide dual functionality as adjuvant and vehicle to localize antigens with stimulated immune cells in the same draining lymph node. Using streptavidin as a model antigen, which can be loaded directly onto the bNP surface, we evaluated the kinetics of lymph node occupancy and adaptive immune responses in wildtype C57BL/6 mice. Antigen exposure in vivo was significantly improved through surface loading onto bNPs, and we developed a working kinetic model to account for the retention of both particles and antigen in draining lymph nodes. We observed enhanced T cell responses and antigen-specific B cell response in vivo when antigen was delivered on the particle surface. This work highlights the advantage of combining intrinsic adjuvant and antigen loading in a single entity, and the utility of kinetic modeling in the understanding of particle-based vaccines. STATEMENT OF SIGNIFICANCE: Development of safe and effective subunit vaccines depends on effective formulations that render optimized exposure and colocalization of antigens and adjuvants. In this work, we utilize a nanoparticle system which features self-adjuvanting properties and allows for surface loading of recombinant protein antigens. Using in vivo imaging, we demonstrated prolonged co-localization of the antigen and adjuvant particles in draining lymph nodes and provided evidence of B cell activation for up to 21 days following subcutaneous injection. A pharmacokinetic model was developed as a step towards bridging the translational gap between particulate-based vaccines and observed outcomes. The results have implications for the rational design of particle-based vaccines.
通过疫苗接种产生的保护性免疫源自主要在从免疫接种部位引流的淋巴结中发育的适应性免疫反应。与肌肉内途径相比，皮下给药允许直接和快速进入淋巴管，但可溶性蛋白质抗原在淋巴结中的积累受到限制。亚单位疫苗还需要免疫刺激佐剂，这些佐剂可能不会与抗原同时在同一淋巴结中积累。在此，我们报告了使用生物素化聚（乳酸-共-乙醇酸）纳米颗粒（bNP）来增强模型蛋白抗原向淋巴管的递呈。bNP 提供双重功能，既作为佐剂又作为载体，将抗原与刺激免疫细胞定位在同一引流淋巴结中。使用链霉亲和素作为模型抗原，其可以直接加载到 bNP 表面，我们评估了野生型 C57BL/6 小鼠淋巴结占据和适应性免疫反应的动力学。通过表面加载到 bNP 上，体内抗原暴露得到显著改善，我们开发了一个工作动力学模型来解释在引流淋巴结中颗粒和抗原的保留。当抗原在颗粒表面递呈时，我们观察到体内 T 细胞反应和抗原特异性 B 细胞反应增强。这项工作强调了将内在佐剂和抗原加载结合在单个实体中的优势，以及在理解基于颗粒的疫苗时使用动力学模型的效用。
安全有效的亚单位疫苗的开发取决于有效的制剂，这些制剂可以优化抗原和佐剂的暴露和共定位。在这项工作中，我们利用一种纳米颗粒系统，该系统具有自佐剂特性，并允许表面加载重组蛋白抗原。通过体内成像，我们证明了抗原和佐剂颗粒在引流淋巴结中的共定位时间延长，并提供了在皮下注射后长达 21 天的 B 细胞激活证据。开发了一个药代动力学模型，作为缩小基于颗粒的疫苗和观察结果之间转化差距的一步。结果对基于颗粒的疫苗的合理设计具有重要意义。
