A Recombinant Protein Vaccine Against Coccidioidomycosis

描述（由申请方提供）：球孢子菌是一种空气传播的真菌病原体，可在免疫功能正常的个体中引起轻度至重度呼吸道疾病（球孢子菌病;圣华金河谷热）。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。虽然很少有危及生命的疾病，球孢子菌引起超过40%的感染个体的显著发病率，并负责与长期治疗相关的高医疗保健费用。虽然大约一半的球孢子菌感染者只会感到轻微的不适，并且不会寻求医疗干预，但大量的临床证据表明，呼吸道疾病的重新激活可能会在最初的损伤后数月至数年内发生。从症状性感染中恢复通常赋予终身免疫力以防止再感染，这表明接种球孢子菌病疫苗是可行的。我们已经表明，疾病易感的BALB/c和C57 BL/6小鼠可以通过接种基因工程的病原体无毒菌株而完全免受球虫感染。初步研究表明，这种突变株的寄生细胞壁的去污剂提取的蛋白质部分保护小鼠免受肺球孢子菌病。在这个建议中，我们概述了一种新的策略，开发一个表位驱动的嵌合疫苗的基础上的一个子集的细胞壁衍生的抗原的活疫苗株的球孢子虫接口与宿主免疫系统，并引发对球孢子虫感染的保护性反应。在具体目标1中，我们将在球孢子菌病小鼠模型中鉴定、结构表征、表达和测试球孢子菌属基因工程疫苗株寄生细胞壁提取物衍生的T细胞反应蛋白（Tcrp）的保护功效。在特异性目标2中，我们将比较基于特异性目标1选择的非糖基化重组蛋白与相同选择的重组蛋白的基因工程N-糖基化、O-糖基化以及N-和O-糖基化形式的保护效力，并评价甘露糖受体在刺激保护性免疫中的参与。在具体目标3中，我们将选择混杂的，人类主要组织相容性复合体（（MHC）II结合表位确定的候选疫苗具有最高的保护效力，如确定的具体目标1和2，到嵌合疫苗，并评估其能力，以保护人类MHCII表达转基因小鼠肺部感染球孢子虫。我们认为，这种表位驱动的疫苗可以同时直接免疫反应的多个显性和亚显性表位，从而诱导强大和持久的保护球孢子菌病。 公共卫生相关性：该提案的目标是开发一种针对球孢子菌病（圣华金谷热）的表位驱动的重组蛋白疫苗，该疫苗将首先在呼吸道疾病的转基因小鼠模型中进行评估（本项目），并最终进入人体临床试验。

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.