Mechanisms of STING-Mediated Mucosal Vaccine Adjuvant Activity of Cyclic di-GMP

描述（由申请人提供）：本提案的目标是揭示STING（干扰素基因刺激因子）介导环二gmp （CDG）粘膜疫苗佐剂活性的体内机制。粘膜免疫最能有效地诱导粘膜保护性免疫反应。然而，目前批准的大多数人类疫苗都是全身注射，通常不能引起有效的粘膜免疫。粘膜减毒活疫苗存在安全性和可接受性问题，而经粘膜途径接种的纯化抗原通常免疫原性较差。CDG具有很强的粘膜免疫原性，因此被认为是一种很有前途的粘膜疫苗佐剂。CDG发挥其粘膜佐剂作用的机制尚不清楚，这阻碍了CDG作为有效粘膜佐剂的进一步发展。STING，也被称为MPYS/MITA，是CDG的受体。我们最近发现，经鼻CDG/Ag免疫后，STING-/-小鼠不能产生Ag特异性抗体或TH1-TH2-TH17 T细胞反应。我们进一步发现sting依赖性的TNF-a对体内CDG佐剂活性至关重要。鼻内共给药CDG/Ag可诱导肺和鼻相关淋巴组织（NALT）的免疫反应。在这里，我们将使用TNFR1-/- tnfr2 -/-和条件STING-/-小鼠来解剖CDG/STING诱导的肺和NALT佐剂活性的体内机制。我们将同时采用模型Ag OVA和肺炎球菌表面蛋白A (PspA) Ag进行研究。树突状细胞（DC）在佐剂活性中起核心作用。我们假设CDG诱导sting依赖的炎症信号，直接或间接激活DC来执行CDG的佐剂活性。为实现这一目标，提出了两个具体目标。目的1。确定STING如何调节cdg诱导的DC佐剂活性。目标2。确定TNF-a如何调节cdg诱导的佐剂活性。目前，还没有一种含有粘膜佐剂的疫苗制剂被批准用于人类。我们的研究所产生的知识可以帮助推进CDG作为人类使用的有效粘膜疫苗佐剂的发展。

DESCRIPTION (provided by applicant): The goal of this proposal is to uncover the in vivo mechanisms by which STING (Stimulator of interferon genes) mediates the mucosal vaccine adjuvant activity of cyclic di-GMP (CDG). Protective mucosal immune responses are most effectively induced by mucosal immunization. However, most of the currently approved human vaccines are administered systemically and generally fail to elicit effective mucosal immunity. Live attenuated mucosal vaccines present safety and acceptability issues while purified antigens are generally poor immunogenic when administered by the mucosal route. CDG exhibits potent mucosal immunogenicity thus, has been explored as a promising mucosal vaccine adjuvant. The mechanism by which CDG executes its mucosal adjuvant activity is unknown, which hinders the further development of CDG as an efficacious mucosal adjuvant. STING, also known as MPYS/MITA, is a receptor for CDG. We recently showed that STING-/- mice fail to generate Ag-specific antibody production or TH1-TH2-TH17 T cell response after intranasal CDG/Ag immunization. We further discovered that STING-dependent TNF-a is essential for CDG adjuvant activity in vivo. Intranasal co-administration of CDG/Ag induces immune response in lung and nasal-associated lymphoid tissue (NALT). Here, we will use TNFR1-/-TNFR2-/- and conditional STING-/- mice to dissect the in vivo mechanism of CDG/STING-induced adjuvant activity in lung and NALT. We will adopt both the model Ag OVA and pneumococcal surface protein A (PspA) Ag for our study. Dendritic cells (DC) play a central role in adjuvant activity. We hypothesize that CDG induces STING-dependent inflammatory signals that activate DC directly or indirectly to execute the adjuvant activity of CDG. Two specific Aims are proposed to carry out this objective. Aim 1. Determine how STING regulates CDG-induced adjuvant activity in DC. Aim 2. Determine how TNF-a regulates CDG-induced adjuvant activity. Currently, there is no vaccine formulation containing a mucosal adjuvant approved for human use. The knowledge generated by our studies can help advance the development of CDG as an efficacious mucosal vaccine adjuvant for human use.