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炭疽疫苗（DAAV），可同时提供针对杆菌和毒素的保护。由炭疽杆菌引起的系统性炭疽感染导致广泛的败血症、毒血症和几乎不可避免的死亡。炭疽的发病机制涉及两个关键过程，即，细菌的复制和毒素的释放。这种杆菌用聚γ-D-谷氨酸（PGA）胶囊保护自己，以逃避免疫监视，同时分泌大量毒素。因此，我们假设一个有效的策略需要既杀死杆菌又破坏毒素。我们进一步假设，可以基于两个主要的毒力因子，特别是芽孢杆菌荚膜PGA和毒素核心保护性抗原（PA）构建AAV。我们的初步研究表明，PGA-PA结合物诱导有效的抗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命攻击。这种疫苗比现有的仅针对炭疽毒素的疫苗优越上级。 我们建议的研究重点是进一步开发和优化PA/PGA为基础的DAAV。我们将通过系统地改变它们的结构来制备三类DAAV构建体（DAAV-X、E和C）的文库。我们将通过比较它们引发抗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性杆菌攻击的能力来获得最佳构建体。将测试优化的DAAV在保护小鼠和兔免受炭疽孢子攻击方面的功效。 目标1.优化“交联”PGA-PA缀合物（DAAV-X）。 目标2.创建和优化“末端连接”PGA-PA缀合物（DAAV-E）。 目标3：研制PA和PGA结合物（DAAV-C）组合炭疽疫苗。 目标4。评价优化的DAAV候选物在炭疽感染的各种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.