Glucan Particles as a Vaccine Platform for Protective Immunity

描述（由申请方提供）：该提案的重点是开发葡聚糖颗粒（GP）作为一种新型疫苗平台和佐剂，促进保护性T细胞和抗体应答。GP是中空的，高度纯化的酵母细胞壁，主要由？1，3-葡聚糖。初步研究表明，在用抗原“加载”的GP免疫小鼠后，具有稳健和持久的适应性T细胞和抗体应答。此外，用含有来自荚膜组织胞浆菌（Hc）的抗原的GP接种的小鼠存活，否则致死的实验性组织胞浆菌病。这些实验将解决中心假设，即负载抗原的GP通过警告免疫系统“危险”的存在、将抗原引导到DC中并刺激保护性适应性T和B细胞应答来形成有效的疫苗平台。进一步假设，通过向GP平台添加其他佐剂（例如TLR激动剂和靶向炎症负调节因子的siRNA）可以有利地操纵免疫应答。目的1是破译由GP刺激的传入通路，形成T细胞和抗体反应。待检验的假设是“施用含有包裹的Ag的GP导致补体活化、DC通过补体受体和Dectin-1的摄取、含有GP的DC向引流淋巴结的迁移以及刺激稳健的适应性免疫应答，包括抗体和Th 1/Th 17-偏向的CD 4 + T细胞应答”。目的二是研究复合于GP的真菌抗原对小鼠抗丙型肝炎病毒感染的保护作用。待检验的假设是“DC对携带抗原的GP的摄取形成免疫应答以产生保护性Th 1和/或Th 17应答”。目的3是探索增强GP平台免疫原性的新方法。待检验的假设是“GP配制的疫苗保护免受HC攻击的能力可以通过先天免疫应答的特异性刺激剂来增强”。我们预计，在资助期结束时，我们将使用FDA批准的材料创建基于GP的疫苗，这些材料能够引发稳健和持久的抗体和Th 1-/Th 17-偏倚应答，保护免疫活性和免疫功能低下的小鼠免受Hc的攻击。此外，我们预期通过改变疫苗的组成（例如通过添加TLR配体或siRNA），我们将积极影响应答的性质。这些研究解决了NIH确定的开发疫苗的需求，以保护流行地区免疫功能低下和免疫功能正常的个体免受组织胞浆菌病的侵害。此外，这些研究应该建立有关基于GP的疫苗平台功效的原则证明，这些平台应该适用于其他疫苗可预防的疾病，并构成最终人体测试的基础。

DESCRIPTION (provided by applicant): This proposal is focused on developing glucan particles (GPs) as a novel vaccine platform and adjuvant that promotes protective T cell and antibody responses. GPs are hollow, highly purified yeast cell walls composed predominantly of ?-1,3-glucan. Preliminary studies demonstrate robust and long-lasting adaptive T cell and antibody responses following immunization of mice with GPs "loaded" with antigen. Moreover, mice vaccinated with GPs containing antigen from Histoplasma capsulatum (Hc) survive otherwise lethal experimental histoplasmosis. The experiments will address the central hypothesis that antigen-loaded GPs make effective vaccine platforms by alerting the immune system to the presence of "danger", directing antigens into DCs and stimulating protective adaptive T and B cell responses. It is further hypothesized that the immune response can be beneficially manipulated by the addition to the GP platform of other adjuvants, such as TLR agonists and siRNA targeting negative regulators of inflammation. Aim 1 is to decipher the afferent pathways stimulated by GPs that shape T cell and antibody responses. The hypothesis to be tested is "administration of GPs containing encased Ag results in complement activation, uptake by DCs via complement receptors and Dectin-1, migration of DCs containing GPs to draining lymph nodes and stimulation of a robust adaptive immune response including antibody and Th1/Th17-biased CD4+ T cell responses". Aim 2 is to investigate the efferent mechanisms by which fungal antigens complexed in GPs protect against Hc infection in mice. The hypothesis to be tested is "uptake of antigen-bearing GPs by DCs shapes the immune response to generate a protective Th1 and/or Th17 response". Aim 3 is to explore novel approaches to boosting the immunogenicity of the GP platform. The hypothesis to be tested is "the capacity of GP-formulated vaccines to protect against challenge with Hc can be augmented by specific stimulators of the innate immune response". We anticipate that at the end of the funding period, we will have created GP-based vaccines using FDA- approved materials capable of eliciting robust and durable antibody and Th1-/Th17-biased responses that protect immunocompetent and immunocompromised mice against challenge with Hc. Moreover, we anticipate that by altering the composition of the vaccines (such as by the addition of TLR ligands or siRNA), we will positively impact the nature of the responses. The studies address an NIH-identified need for development of a vaccine to protect immunocompromised and immunocompetent individuals in endemic regions from histoplasmosis. In addition, the studies should establish a proof of principle regarding the efficacy of GP-based vaccine platforms that should be applicable to other vaccine-preventable diseases and form the basis for eventual testing in humans.