A tri-antigen nasal anthrax vaccine against toxins and vegetative bacilli

描述(申请人提供)：炭疽芽胞是一种吸引人的生物武器，可以通过许多不同的方式传播，以引发生物恐怖主义，例如9·11恐怖袭击后故意污染美国邮件。吸附的炭疽疫苗(AVA)是美国唯一的人类炭疽疫苗，获得了预防皮肤炭疽的许可，需要在随后的年度加强免疫中进行初始多次注射。因此，迫切需要开发一种有效且易于管理的疫苗来预防炭疽感染，特别是吸入性炭疽，这是炭疽最致命的形式。新的炭疽疫苗开发的重点是基于炭疽毒素的纯化保护性抗原(PA)蛋白的疫苗的生产。然而，研究表明，除PA外，炭疽疫苗还应包括其他抗原，如与PA结合形成炭疽致命毒素的致死因子(LF)，以及围绕营养炭疽杆菌的聚γ-D-谷氨酸(PGA)胶囊，以获得更有效的保护。鼻腔多抗原炭疽疫苗将是有利的，不仅因为它将易于管理，还因为它有望诱导针对全身隔室和呼吸道粘膜组织中所有抗原的免疫反应，吸入的炭疽孢子通过这些组织进入宿主。来自最近研究的数据表明，抗PA粘膜反应在预防动物吸入性炭疽病挑战中的重要性。我们建议开发一种有效的鼻腔炭疽疫苗，通过将63 kDa形式的PA、灭活的Lf突变体和PGA作为抗原引入到我们开发的基于脂质的颗粒疫苗载体中，从而诱导针对炭疽毒素和营养杆菌的特异性系统和粘膜免疫反应。我们推测，这种三抗原鼻腔疫苗在预防吸入性炭疽感染方面将比仅以PA为基础的全身注射疫苗更有效。我们的具体目的是确定该三抗原鼻腔炭疽疫苗在小鼠体内诱导的免疫应答(目标1)，评价其诱导的抗毒素和抗细菌活性(目标2)，并验证该疫苗在预防小鼠肺炭疽孢子攻击方面的有效性(目标3)。该项目的完成有望为进一步将该疫苗开发成一种有效且易于管理的人类鼻腔炭疽疫苗提供坚实的科学基础。针对炭疽毒素和杆菌的鼻腔注射多抗原炭疽疫苗原型的开发及其在小鼠模型中的有效性验证，将为开发新一代人用炭疽疫苗奠定坚实的基础，这是在隐蔽炭疽暴发情况下有效大规模免疫所迫切需要的。同样的疫苗或其改良版本也可以用于农业行业为牛接种疫苗。

DESCRIPTION (provided by applicant): Bacillus anthracis spores are an appealing biological weapon, which can be distributed through many different means to cause bioterrorism, such as the intentional contamination of the U.S. mail after the September 11 terrorist attacks. Anthrax vaccine adsorbed (AVA), the only human anthrax vaccine in the U.S., was licensed for the prevention of cutaneous anthrax and requires initial multiple injections with subsequent annual boosters. Thus, there is a critical need to develop an efficacious and easily administrable vaccine to protect against anthrax infection, especially the inhalation anthrax, the most lethal form of anthrax. New anthrax vaccine development has been focused on the production of a vaccine based on purified protective antigen (PA) protein of the anthrax toxin. However, it was shown that, besides the PA, other antigens such as the lethal factor (LF), a protein that binds to PA to form anthrax lethal toxin, and the poly-gamma-D-glutamic acid (PGA) capsule surrounding the vegetative anthrax bacilli, should also be included in an anthrax vaccine for more effective protection. A nasal multi- antigen anthrax vaccine will be advantageous not only because it will be ease to administer, but also because it is expected to induce immune responses against all antigens in both the systemic compartment and the mucosal tissues of the respiratory tract, through which inhaled anthrax spores enter hosts. Data from recent studies have indicated the importance of the anti-PA mucosal responses in preventing against inhalational anthrax challenges in animals. We propose to develop an efficacious nasal anthrax vaccine that can induce specific systemic and mucosal immune responses against both the anthrax toxins and the vegetative bacilli by incorporating a 63 kDa form of PA, an inactivated LF mutant, and PGA as antigens into a lipid-based particulate vaccine carrier we have developed. We hypothesize that that this tri-antigen nasal vaccine will be more effective in preventing against an inhalational anthrax infection than the systemic injection of a vaccine based on PA alone. Our specific aims are to define the immune responses induced by this tri-antigen nasal anthrax vaccine in mice (aim 1), to evaluate the anti-toxin and anti-bacillus activities induced by it (aim 2), and to validate the efficacy of this vaccine in preventing against a pulmonary anthrax spore challenge in mice (aim 3). The completion of this project is expected provide a sound scientific foundation for further developing this vaccine into an efficacious and easily administrable nasal anthrax vaccine for humans. The development of a prototype nasally administrable multi-antigen anthrax vaccine that targets both anthrax toxins and bacilli and the validation of its efficacy in a murine model will provide a sound foundation for the development of a new generation human anthrax vaccine, which is urgently needed for effective mass immunization in case of a covert anthrax outbreak. The same vaccine or its modified version can also be used in agricultural industries to vaccinate cattle.