Glucan Particles as a Vaccine Platform for Protective Immunity

描述(由申请人提供)：这项提案的重点是开发葡聚糖颗粒(GP)作为一种新的疫苗平台和佐剂，促进保护性T细胞和抗体反应。GP是一种中空的、高纯度的酵母细胞壁，主要由β-1，3-葡聚糖组成。初步研究表明，用GPs“装载”抗原的小鼠免疫后，可产生强大而持久的适应性T细胞和抗体反应。此外，接种含有来自组织胞浆菌(HC)抗原的GPs的小鼠在其他致命的实验性组织胞浆菌病中存活。这些实验将解决一个中心假设，即装载抗原的GP通过提醒免疫系统注意“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细胞反应，从而成为有效的疫苗平台。进一步假设，在GP平台上添加其他佐剂，如TLR激动剂和靶向炎症负调控因子的siRNA，可以有益地操纵免疫反应。目的1是破译GP刺激的形成T细胞和抗体反应的传入通路。将被测试的假设是“给予含有包膜抗原的GPs导致补体激活，树突状细胞通过补体受体和Dectin-1摄取，含有GPs的树突状细胞迁移到引流淋巴结，并刺激强大的适应性免疫反应，包括抗体和Th1/Th17偏向的CD4+T细胞反应”。目的2研究复合在GPs中的真菌抗原对小鼠抗HC感染的传出机制。待检验的假设是“DC摄取携带抗原的GP塑造免疫反应，以产生保护性的Th1和/或Th17反应”。目的3是探索增强GP平台免疫原性的新方法。需要检验的假设是“GP疫苗抵御HC攻击的能力可以通过先天免疫反应的特定刺激物来增强”。我们预计，在资助期结束时，我们将使用FDA批准的材料开发出基于GP的疫苗，该疫苗能够诱导强大而持久的抗体和Th1/Th17偏向反应，保护免疫能力强和免疫受损的小鼠免受HC的挑战。此外，我们预计，通过改变疫苗的组成(如添加TLR配体或siRNA)，我们将对应答的性质产生积极影响。这些研究解决了美国国立卫生研究院确定的开发疫苗的需求，以保护流行地区免疫受损和免疫能力强的个人免受组织胞浆菌病的影响。此外，这些研究应该建立关于基于GP的疫苗平台有效性的原则证据，该证据应该适用于其他疫苗可预防的疾病，并形成最终在人类身上进行测试的基础。

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.