A Recombinant Protein Vaccine Against Coccidioidomycosis

描述（由申请人提供）：球孢子虫是一种空气传播的真菌病原体，可在免疫正常的个体中引起轻度至重度呼吸道疾病（球孢子菌病；圣华金谷热）。这种真菌栖息在美国西南部德克萨斯州西部和南加州之间的沙漠土壤中。大约有2000万人居住在流行地区。虽然球虫病很少是一种危及生命的疾病，但在40%以上的感染者中引起显著发病率，并造成与长期治疗相关的高额卫生保健费用。虽然大约一半的球虫感染个体只经历轻微的不适，不寻求医疗干预，但大量临床证据表明，呼吸道疾病可能在最初的伤害发生数月至数年后重新激活。从症状性感染中恢复通常可获得对再次感染的终身免疫力，这表明针对球虫菌病的疫苗接种是可行的。我们已经证明，疾病易感的BALB/c和C57BL/6小鼠可以通过接种一种基因工程的、无毒的病原体菌株来完全保护其免受球虫感染。初步研究表明，洗涤剂提取的蛋白质部分的寄生细胞壁的这种突变株保护小鼠对肺球孢子菌病。在这一建议中，我们概述了一种基于球虫活疫苗株细胞壁源性抗原亚群开发表位驱动嵌合疫苗的新策略，该疫苗与宿主免疫系统结合，并引发针对球虫感染的保护性反应。在特异性目标1中，我们将鉴定、结构表征、表达和在球孢子菌病小鼠模型中测试t细胞反应蛋白（Tcrp）的保护作用，这些蛋白来源于球孢子菌基因工程疫苗菌株的寄生细胞壁提取物。在Specific Aim 2中，我们将比较基于Specific Aim 1选择的非糖基化重组蛋白与基因工程的N-糖基化、o -糖基化以及N-和o -糖基化形式的相同选择的重组蛋白的保护效果，并评估甘露糖受体在刺激保护性免疫中的作用。在特异性目标3中，我们将选择在特异性目标1和特异性目标2确定的具有最高保护功效的候选疫苗中鉴定的混杂的人类主要组织相容性复合体（MHC） ii结合表位纳入嵌合疫苗中，并评估其保护表达mhcii的转基因小鼠免受球虫肺部感染的能力。我们认为，这种表位驱动的疫苗可以同时引导免疫应答多个显性和亚显性表位，从而诱导对球孢子菌病的强大和持久的保护。

DESCRIPTION (provided by applicant): Coccidioides is an airborne fungal pathogen that can cause mild to severe respiratory disease (coccidioidomycosis; San Joaquin Valley fever) in immunocompetent individuals. The fungus inhabits desert soil in the Southwestern U.S. between West Texas and Southern California. About 20 million people reside in the endemic region. Although rarely a life-threatening disease, Coccidioides causes significant morbidity in more than 40% of infected individuals, and is responsible for high health care costs related to long term treatment. Although about half of the Coccidioides-infected individuals experience only mild discomfort and do not seek medical intervention, a large body of clinical evidence suggests that reactivation of the respiratory disease may occur months to years after the original insult. Recovery from symptomatic infection typically confers lifelong immunity to reinfection, suggesting that vaccination against coccidioidomycosis is feasible. We have shown that disease- susceptible BALB/c and C57BL/6 mice can be fully protected against coccidioidal infection by vaccination with a genetically engineered, avirulent strain of the pathogen. Preliminary studies have revealed that a detergent extracted protein fraction of the parasitic cell wall of this mutant strain protects mice against pulmonary coccidioidomycosis. In this proposal we outline a novel strategy to develop an epitope-driven chimeric vaccine based upon a subset of cell wall-derived antigens of the live vaccine strain of Coccidioides that interface with the host immune system and elicit a protective response against coccidioidal infection. In Specific Aim 1, we will identify, structurally characterize, express and test in a murine model of coccidioidomycosis the protective efficacy of T-cell-reactive proteins (Tcrp) derived from parasitic cell wall extracts of the genetically-engineered vaccine strain of Coccidioides. In Specific Aim 2, we will compare the protective efficacy of non-glycosylated recombinant proteins selected on the basis of Specific Aim 1 to genetically-engineered N- glycosylated, O-glycosylated, and both N- and O-glycosylated forms of the same selected recombinant proteins, and evaluate the involvement of mannose receptors in the stimulation of protective immunity. In Specific Aim 3, we will incorporate selected promiscuous, human major histocompatibility complex ((MHC) II-binding epitopes identified in vaccine candidates with the highest protective efficacy, as determined by Specific Aims 1 and 2, into a chimeric vaccine and evaluate its ability to protect human MHCII-expressing transgenic mice against pulmonary infection with Coccidioides. We argue that this epitope-driven vaccine can simultaneously direct the immune response to multiple dominant and subdominant epitopes and, thereby, induce robust and durable protection against coccidioidomycosis. PUBLIC HEALTH RELEVANCE: The goal of this proposal is to develop an epitope-driven, recombinant protein-based vaccine against coccidioidomycosis (San Joaquin Valley fever), which will first be evaluated in a transgenic murine model of the respiratory disease (this project), and ultimately moved forward to human clinical trial.