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，可在免疫能力强的个人中引起轻度至严重的呼吸道疾病(球孢子菌病；圣华金河谷热)。这种真菌生活在美国西南部德克萨斯州西部和加利福尼亚州南部之间的沙漠土壤中。约有2000万人居住在疫区。虽然球虫很少是一种危及生命的疾病，但它在40%以上的感染者中会导致显著的发病率，并导致与长期治疗相关的高昂医疗费用。尽管大约一半的球虫感染者只会感到轻微的不适，没有寻求医疗干预，但大量临床证据表明，呼吸道疾病的重新激活可能会在最初的侮辱发生后几个月到几年发生。从有症状的感染中恢复通常会为再次感染提供终身免疫力，这表明接种球孢子菌病疫苗是可行的。我们已经证明，对疾病敏感的BALB/c和C57BL/6小鼠可以通过接种一种基因工程的无毒株球虫来完全保护小鼠免受球虫感染。初步研究表明，这种突变菌株寄生细胞壁的一种洗涤剂提取蛋白部分可以保护小鼠免受肺部球孢子菌病的侵袭。在这项建议中，我们概述了一种新的策略，以球虫活疫苗株细胞壁衍生抗原的子集为基础，开发一种表位驱动的嵌合疫苗，该疫苗与宿主免疫系统接口，并引发针对球虫感染的保护性反应。在具体目标1中，我们将鉴定、结构表征、表达并在球孢子菌病小鼠模型中测试从球孢子虫基因工程疫苗株寄生细胞壁提取物中提取的T细胞反应蛋白(TCRP)的保护效果。在特定目标2中，我们将根据特定目标1选择的非糖基化重组蛋白与相同选择的基因工程重组蛋白的N-糖基化、O-糖基化以及N-和O-糖基化形式的保护效果进行比较，并评估甘露糖受体在保护免疫刺激中的作用。在具体目标3中，我们将把特定目标1和2确定的具有最高保护效力的候选疫苗中确定的混杂的人类主要组织相容性复合体(MHC)II结合表位整合到嵌合疫苗中，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针对多个显性和亚显性表位引导免疫反应，从而诱导对球孢子菌病的强大和持久的保护。 公共卫生相关性：这项提案的目标是开发一种表位驱动的、基于重组蛋白的球孢子菌病疫苗(圣华金河谷热)，该疫苗将首先在呼吸道疾病的转基因小鼠模型(该项目)中进行评估，并最终进入人类临床试验。

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.