Dually Active Anthrax Vaccine Against Bacilli and Toxins

描述(由申请人提供)：我们研究的总体目标是开发一种有效的、双重活性的炭疽疫苗(DAAV)，提供对细菌和毒素的同时保护。炭疽芽孢杆菌全身性炭疽感染可导致广泛的败血症、毒血症，甚至几乎无一例外地死亡。炭疽病的发病机制涉及两个重要的过程，即细菌的复制和毒素的释放。这些细菌用聚γ-D-谷氨酸(PGA)胶囊来保护自己，以逃避免疫监视，同时分泌大量毒素。因此，我们假设一种有效的策略需要既杀死细菌又摧毁毒素。我们进一步假设，DAAV可以基于两个主要的毒力因子，即芽孢杆菌囊膜PGA和毒素核心保护性抗原(PA)构建。我们的初步研究表明，PGA-PA结合物可诱导产生强大的抗PA和抗PGA抗体，并保护免疫小鼠免受炭疽毒素和类似杆菌的致死攻击。这种疫苗优于现有的仅针对炭疽毒素的疫苗。 我们提出的研究重点是进一步开发和优化基于PA/PGA的DAAV。我们将通过系统地改变结构来准备三类DAAV构造体(DAAV-X、E和C)的库。我们将通过比较它们诱导抗PGA和抗PA抗体的能力，以及它们保护小鼠免受致命毒素和毒力杆菌攻击的能力来获得最佳结构。优化后的DAV将被测试其在保护小鼠和兔子免受炭疽孢子攻击方面的有效性。 目的1.优化“交联型”PGA-PA偶联物(DAAV-X)。 目的2.创造和优化“末端连接”的PGA-PA偶联物(DAAV-E)。 目的研制以PA和PGA结合物为基础的组合炭疽疫苗(DAAV-C)。 目的4.评价优化的DAAV候选病毒在不同炭疽感染动物模型中的有效性。

DESCRIPTION (provided by applicant): The overall goal of our study is to develop an effective, dually active anthrax vaccine (DAAV) that confers simultaneous protection against both the bacilli and the toxins. Systemic anthrax infection by Bacillus anthracis results in extensive septicemia, toxemia, and almost invariably death. The pathogenesis of anthrax involves two crucial processes, i.e., replication of bacilli and release of toxins. The bacilli protect themselves with a poly-gamma-D-glutamic acid (PGA) capsule to evade immune surveillance while secreting large amounts of toxins. Hence, we hypothesize that an effective strategy needs to both kill the bacilli and destroy the toxins. We further hypothesize that a DAAV can be constructed based on the two major virulence factors, specifically, the bacillus capsular PGA and the toxin core protective antigen (PA). Our preliminary study demonstrates that PGA-PA conjugates induce potent anti-PA and anti-PGA antibodies and protect immunized mice against lethal challenges with both anthrax toxin and analogous bacilli. Such vaccines are superior to existing vaccines that solely target anthrax toxins. The focus of our proposed study is to further develop and optimize PA/PGA-based DAAVs. We will prepare libraries of three classes of DAAV constructs (DAAV-X, E, and C) by systematically varying their structures. We will derive optimal constructs by comparing their ability to elicit anti-PGA and anti-PA antibodies and their ability to protect mice against challenges with lethal toxins and virulent bacilli. Optimized DAAVs will be tested for their efficacy in protecting mice and rabbits against anthrax spore challenges. Aim 1. To optimize "cross-linked" PGA-PA conjugates (DAAV-X). Aim 2. To create and optimize "end-linked" PGA-PA conjugates (DAAV-E). Aim 3. To develop combination anthrax vaccines consisting of mixtures of PA and PGA-based conjugates (DAAV-C). Aim 4. To evaluate the effectiveness of optimized DAAV candidates in various animal models of anthrax infection.