亚单位或灭活疫苗包含大多数针对病毒和细菌病原体使用的疫苗。然而,与它们的活/减毒对应物相比,这些疫苗通常表现出降低的免疫原性,需要多种加强剂和/或佐剂来引发保护性免疫反应。出于这个原因,佐剂及其改善灭活疫苗反应的机制的研究对于开发具有更高效力的疫苗至关重要。研究表明,佐剂与抗原的直接结合促进了疫苗的免疫原性,具有佐剂和抗原靶向同一细胞的优势。使用这种直接联系的策略,我们开发了一种灭活的甲型流感(IAV)疫苗,该疫苗通过异双功能交联剂与Toll样受体7/8激动剂瑞喹莫德(R848)直接偶联.以前,我们发现,与无佐剂疫苗相比,该疫苗可改善新生非人灵长类动物的保护和病毒清除能力.我们随后发现,用于将R848与病毒缀合的接头的选择改变了疫苗的刺激活性,促进体外分化的DC成熟和促炎细胞因子的产生。有了这些知识,我们探讨了交联剂的选择如何影响这些疫苗的刺激活性.我们发现,接头的选择改变了人单核细胞衍生的树突状细胞(moDC)中通过NF-κB途径的信号传导。Further,我们将分析扩展到人外周血中存在的体内分化APC,复制在体外分化细胞中发现的接头依赖性差异。最后,我们在小鼠模型中证明,接头的选择会影响接种疫苗时产生的IAV特异性IgG抗体的量.这些数据增强了我们对用于改善疫苗免疫原性的缀合方法的理解。
Subunit or inactivated vaccines comprise the majority of vaccines used against viral and bacterial pathogens. However, compared to their live/attenuated counterparts, these vaccines often demonstrate reduced immunogenicity, requiring multiple boosters and or adjuvants to elicit protective immune responses. For this reason, studies of adjuvants and the mechanism through which they can improve inactivated vaccine responses are critical for the development of vaccines with increased efficacy. Studies have shown that the direct conjugation of adjuvant to antigen promotes vaccine immunogenicity, with the advantage of both the adjuvant and antigen targeting the same cell. Using this strategy of direct linkage, we developed an inactivated influenza A (IAV) vaccine that is directly conjugated with the Toll-like receptor 7/8 agonist resiquimod (R848) through a heterobifunctional crosslinker. Previously, we showed that this vaccine resulted in improved protection and viral clearance in newborn nonhuman primates compared to a non-adjuvanted vaccine. We subsequently discovered that the choice of linker used to conjugate R848 to the virus alters the stimulatory activity of the vaccine, promoting increased maturation and proinflammatory cytokine production from DC differentiated in vitro. With this knowledge, we explored how the choice of crosslinker impacts the stimulatory activity of these vaccines. We found that the linker choice alters signaling through the NF-κB pathway in human monocyte-derived dendritic cells (moDCs). Further, we extended our analyses to in vivo differentiated APC present in human peripheral blood, replicating the linker-dependent differences found in in vitro differentiated cells. Finally, we demonstrated in a mouse model that the choice of linker impacts the amount of IAV-specific IgG antibody produced in response to vaccination. These data enhance our understanding of conjugation approaches for improving vaccine immunogenicity.