B. anthracis:passive immunization with anticapsular mAb

描述（由申请人提供）：炭疽芽孢杆菌被抗吞噬胶囊包围，该胶囊由多γ - d -谷氨酸（PGA）组成。尽管炭疽热胶囊在炭疽的发病过程中起着至关重要的作用，但对炭疽热胶囊的免疫反应却很少受到关注，PGA抗体的保护作用尚不清楚。该提议的总体假设是PGA抗体对炭疽具有保护作用。本研究的目的是建立PGA单克隆抗体（mab）文库，并在体外和体内评价抗体的性质。在初步研究中，通过PGA与一种强效的新型b细胞佐剂联合免疫小鼠，产生了强烈的同型转换（IgG）和亲和成熟抗体应答。在很短的时间内已经产生了5个分泌抗pga IgG的杂交瘤，并且具有不同表位特异性的其他单克隆抗体的生产正在进行中。因此，在小鼠中产生强大抗体反应和生产lgG单克隆抗体的可行性已被证明。提案的具体目标是我)生成一个图书馆的PGA免疫球蛋白马伯代表一系列的表位特异性,2)评估马伯的免疫化学绑定可溶性和荚膜PGA, iii)产生免疫球蛋白子类开关变量的PGA马伯,iv)评估体外PGA马伯的活动,可能是预测的保护,和v)评估表位特异性抗体和同形像的角色在决定保护皮肤和吸入炭疽的小鼠模型。针对这种胶囊进行疫苗开发或免疫治疗是有吸引力的，因为抗胶囊免疫不会因抗生素耐药性或对基于毒素的免疫具有抗性的炭疽毒素工程而受到损害。所提议的保护效力的确定对于任何针对炭疽芽孢杆菌胶囊的主动或被动免疫工作都是至关重要的，并将为被动免疫作为炭疽芽孢杆菌暴露前或暴露后免疫治疗的概念提供证据。

DESCRIPTION (provided by applicant): Bacillus anthracis is surrounded by an antiphagocytic capsule that is composed of poly-gamma-D-glutamic acid (PGA). Despite an essential role for the capsule in the pathogenesis of anthrax, the immune response to the capsule has received little attention, and the protective role of PGA antibody is unknown. The overall hypothesis for this proposal is that PGA antibodies are protective against anthrax. The goal for the study is to generate a library of PGA monoclonal antibodies (mAbs) and to evaluate the properties of the antibodies in vitro and in vivo. In preliminary studies, a strong isotype-switched (IgG) and affinity-matured antibody response has been generated in mice through immunization with PGA in combination with a potent and novel B-cell adjuvant. Five hybridomas that secrete anti-PGA IgG have been generated in a very short time, and production of additional mAbs having distinct epitope specificities is in progress. Thus, the feasibility for generation of a robust antibody response in mice and for production of lgG mAbs has been demonstrated. The specific aims of the proposal are to i) generate a library of PGA IgG mAbs that represent a spectrum of epitope specificities, ii) evaluate the immunochemistry of mAb binding to soluble and capsular PGA, iii) generate IgG subclass switch variants of PGA mAbs, iv) assess in vitro activities of PGA mAbs that may be predictive of protection, and v) evaluate the role of epitope specificity and antibody isotype in determining protection in murine models of cutaneous and inhalation anthrax. Targeting the capsule for vaccine development or immunotherapy is attractive because anticapsularimmunity would not be compromised by antibiotic resistance or engineering of an anthrax toxin that is resistant to toxin-based immunity. The proposed determination of protective efficacy is central to any effort at active or passive immunization that targets the B. anthracis capsule and would provide proof of concept for passive immunization as a pre- or post-exposure immunotherapy for anthrax.