Glucan Particles as a Vaccine Platform for Protective Immunity

描述（由申请人提供）：该提案的重点是开发葡聚糖颗粒（GPs）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。GPs是中空的，高度纯化的酵母细胞壁，主要由-1,3-葡聚糖组成。初步研究表明，在“装载”抗原的GPs小鼠免疫后，适应性T细胞和抗体反应稳健且持久。此外，接种含有荚膜组织浆体（Hc）抗原的GPs疫苗的小鼠在其他致命的实验性组织浆体病中存活下来。这些实验将解决一个核心假设，即满载抗原的GPs通过提醒免疫系统“危险”的存在、将抗原引导到dc中并刺激保护性适应性T细胞和B细胞反应，从而成为有效的疫苗平台。进一步的假设是，通过在GP平台上添加其他佐剂，如TLR激动剂和靶向炎症负调节因子的siRNA，可以有益地操纵免疫反应。目的1是破译由形成T细胞和抗体反应的GPs刺激的传入通路。要验证的假设是“给药含有包裹银的全身性蛋白导致补体激活，dc通过补体受体和Dectin-1摄取，含有全身性蛋白的dc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是研究真菌抗原在全球定位系统中对小鼠Hc感染的保护作用的传出机制。待验证的假设是“dc对携带抗原的gp的摄取会形成免疫反应，从而产生保护性Th1和/或Th17反应”。目的3是探索提高GP平台免疫原性的新方法。待验证的假设是“gp配方疫苗抵御丙型肝炎攻击的能力可以通过先天免疫反应的特定刺激物得到增强”。我们预计在融资期结束时，我们将使用FDA批准的材料制造出基于gpd的疫苗，这些疫苗能够引发强大和持久的抗体和Th1 / th17偏倚反应，保护免疫正常和免疫功能低下的小鼠免受Hc的攻击。此外，我们预计通过改变疫苗的组成（例如通过添加TLR配体或siRNA），我们将对反应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功能低下和免疫功能正常的个体免受组织浆菌病的侵害。此外，这些研究应建立一个关于基于gp的疫苗平台有效性的原则证明，该平台应适用于其他疫苗可预防的疾病，并为最终的人体试验奠定基础。

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.