Targeting Heme Transporters for Improved Vaccines against Anthrax

描述（由申请人提供）：在一个大城市，可能没有比炭疽杆菌孢子（炭疽病的病原体）的恶意释放更严重的生物威胁了。由于吸入形式的死亡率接近90%，并且孢子可以保持多年的传染性，因此对这种致命疾病的保护至关重要。美国炭疽疫苗在动物模型中诱导毒素中和保护。然而，它的成分是未知的，它的免疫原性是短暂的，并且对某些菌株的炭疽杆菌没有保护作用。我们的初步数据表明，芽孢杆菌近铁转运蛋白（NEAT）在感染过程中具有获取和输入宿主血红素的功能，可以保护小鼠在接种炭疽疫苗后免受炭疽疾病的侵袭。在这个应用中，我们利用我们对NEAT蛋白功能的分子理解来创建和测试一种由血红素转运蛋白组成的新型疫苗。我们假设接种NEAT芽孢杆菌蛋白可以诱导中和或调理素介导的对炭疽杆菌的反应，并保护脊椎动物宿主在感染最毒力菌株后免受炭疽杆菌的侵袭。目的1：确定接种NEAT蛋白后的保护机制。重组NEAT结构域将通过小鼠炭疽模型评估其有效性。保护性抗体将通过血红素获取和调理素介导的测定来评估其活性。目的2：确定接种NEAT蛋白疫苗是否能预防全毒力炭疽芽胞杆菌。将使用一种被广泛接受的豚鼠模型来评估NEAT蛋白对全毒性炭疽杆菌的保护能力

DESCRIPTION (provided by applicant): There may not be a more significant biological threat than the malevolent release of B. anthracis spores, the causative agent of anthrax disease, over a major metropolis. With the inhalational form approaching 90% mortality, and a spore that can remain infectious for years, protection against this deadly disease is critical. The U.S. anthrax vaccine induces toxin-neutralizing protection in animal models. However, its composition is unknown, its immunogenicity is short-lived, and it does not protect against some strains of B. anthracis. Our preliminary data suggests bacillus near-iron transporter (NEAT) proteins, which function to acquire and import host heme during infection, can protect mice against anthrax disease following vaccination. In this application, we use our molecular understanding of NEAT protein function to create and test a novel vaccine composed of heme transporters. We hypothesize vaccination with bacillus NEAT proteins will induce neutralizing or opsonin-mediated responses to B. anthracis and protect vertebrate hosts from full-blown anthrax after infection with the most highly-virulent strains. Aim 1: Determine the mechanism of protection following vaccination with NEAT proteins. Recombinant NEAT domains will be evaluated for efficacy using a murine model of anthrax. Protective antibodies will be evaluated for activity using heme acquisition and opsonin-mediated assays. Aim 2: Determine if vaccination with NEAT proteins protects against fully-virulent B. anthracis. NEAT proteins will be evaluated for their ability to protect against fully-virulent B. anthracis using a well-accepted guinea pig model of anthrax under high-containment. Safe antigens will also be constructed by mutagenesis of key residues that mediate NEAT functionality. Since NEAT proteins are conserved in every major genus of Gram-positive pathogenic bacteria, this work also has universal appeal for vaccine development against related species.