Development of a multivalent vaccine against Coccidioides infection

项目摘要 球孢子菌病影响美国西南部、墨西哥北部和零星地区的居民 来自南美洲。据估计，美国有15万人感染了球虫 每年一次。迫切需要开发更好的化学疗法和防治球虫的疫苗，这一需求尚未得到满足 感染。这项研究旨在优化一种新的疫苗的保护效果和免疫机制。 研制了球孢子菌病多价疫苗。疫苗由一种重组嵌合体组成 多肽抗原(RCPA2)由4个已鉴定的免疫原性最强的片段组成 球虫抗原和5个预测的T细胞表位。初步研究表明，强健和持久 表达人MHC II基因的人类白细胞抗原-DR4转基因小鼠免疫后适应性T细胞应答 葡聚糖-甲壳素颗粒(GCP)“装载”rCPA2。此外，优化的GCP-rCPA2疫苗提供了 在5种测试佐剂形式中保护效果最好，可与减毒活ΔT疫苗相媲美。 RCPA+GCP疫苗由接种地点的巨噬细胞和树突状细胞处理得很好 介导差异免疫基因表达，导致抗原提呈增强，Th1-和Th17- 混合极化。Th17免疫已被证明是疫苗免疫不可缺少的。 球孢子菌病。这一提议的中心假设是优化的rCPA2抗原装载在 具有FDA批准的载体的GCP佐剂/递送系统可以诱导广泛的保护性免疫 用于人源化小鼠对抗这两种球虫的感染。我们的目标是调查 人源化小鼠模型优化的GCP-rCPA2疫苗的保护机制 球孢子菌病与人体免疫细胞。有三个具体目标：目标一是创造一个优化的 RCPA2可诱导对这两个物种的广谱和持久的保护性免疫 球孢子虫。RCPA2上的人类T细胞表位将被映射为3个常见的人类MHC II等位基因。的确有 不同分离株的形态和基因组差异较大。这个 优化的抗原将包括来自两种球虫的多个人类白细胞抗原的优势表位 等位基因。将测试优化疫苗的保护效力，以对抗每种疫苗的两个选定菌株 球虫属中抗原同源性最低的种。目标2是优化GCP 用于诱导保护性Th1和Th17混合反应的佐剂配方 使用人类和小鼠的APC和CD4+T细胞。优化的GCP佐剂/输送系统将是 为最大限度地提高防护效果而创造的。目的3研究疫苗诱导的保护机制。 球孢子菌病小鼠模型的Th1和Th17反应。这项工程完成后， 优化和保护性的GCP2-rCPA2疫苗将被确定为临床试验的进展 评价其对球孢子菌病的安全性和保护效果。

Project Summary Coccidioidomycosis affects residents in the southwestern United States, northern Mexico and scattered areas of South America. An estimated 150,000 people in the United States become infected with Coccidioides annually. There is an urgent unmet need to develop better chemotherapies and a vaccine against Coccidioides infection. This proposed study is to optimize protective efficacy and delineate immune mechanisms of a newly developed multivalent vaccine against coccidioidomycosis. The vaccine consists of a recombinant chimeric polypeptide antigen (rCPA2) composed of the most immunogenic fragments of 4 previously identified Coccidioides antigens and 5 predicted T-cell epitopes. Preliminary studies demonstrate robust and long-lasting adaptive T-cell responses following vaccination of human MHC II-expressing HLA-DR4 transgenic mice with glucan-chitin particles (GCPs) “loaded” with rCPA2. Furthermore, optimized GCP-rCPA2 vaccine affords the best protective efficacy among 5 tested adjuvant formations and comparable to a live, attenuated ΔT vaccine. The rCPA+GCP vaccine is well processed by macrophages and dendritic cells at the vaccination sites and mediates differential immune gene expressions leading to enhanced antigen presentation and Th1- and Th17- mixed polarization. Th17 immunity has shown to be indispensable for vaccine immunity against coccidioidomycosis. The central hypothesis of this proposal is that an optimized rCPA2 antigen loaded in GCP adjuvant/delivery system with an FDA-approved carrier can elicit a broad spectrum of protective immunity for humanized mice against infection with both species of Coccidioides. The goal is to investigate the protective mechanisms of the optimized GCP-rCPA2 vaccine using humanized murine models of coccidioidomycosis and human immune cells. There are 3 Specific Aims: Aim 1 is to create an optimized rCPA2 that can induce a broad spectrum and durable protective immunity against both species of Coccidioides. Human T-cell epitopes on rCPA2 will be mapped for 3 common human MHC II alleles. There is considerable morphological and genomic diversity among different isolates of C. posadasii and C. immitis. The optimized antigen will include dominant epitopes derived from both species of Coccidioides for multiple HLA alleles. Protective efficacy of the optimized vaccine will be tested to against two selected isolates of each Coccidioides species that present with the least homology of the antigens. Aim 2 is to optimize the GCP adjuvant formulation for eliciting a protective Th1- and Th17-mixed response against Coccidioides infection using both human and mouse APCs and CD4+ T cells. An optimized GCP adjuvant/delivery system will be created to maximize protective efficacy. Aim 3 To study the vaccine induced protective mechanism that guides Th1 and Th17 responses using murine models of coccidioidomycosis. Upon completion of this project an optimized and protective GCP2-rCPA2 vaccine will be identified for advancement to clinical trials for assessment of it safety and protective efficacy against coccidioidomycosis.