Optimization of therapeutic mAbs to carbapenem resistant Klebsiella clone ST258

碳青霉烯耐药肺炎克雷伯菌（CR-Kp）是最常见的革兰阴性菌 多重耐药细菌在美国医院。CR-Kp主要引起肺炎、败血症和泌尿道感染 感染，并且在军事人员中，复杂的侵入性伤口感染也是如此。大多数患者都是这样做的。 卫生保健相关环境中的病原体。士兵们处于危险之中，因为他们通常会长期逗留 在医院和康复中心，当他们从战斗中受伤后恢复过来。死亡率 侵袭性CR-Kp感染很高，通常超过50%。一个问题是，大多数CR-Kp感染是 诊断得太晚，使用多粘菌素等抗生素进行经验性治疗是有毒的，而且也会受到影响 甚至对这些抗生素也产生了耐药性。此应用程序的目标是优化两个现有的铅 单克隆抗体（mAb），其结合CR-Kp的不同多糖囊（CPS）。两个进化枝1 和进化枝2 CPS特异性IgG mAb是可用的，并且预期覆盖大多数CR-Kp菌株 特别是属于克隆群CG 258群的更强毒力的进化枝2的那些。基于他人 和我们发表的经验，我们提出了几种策略来测试这些单克隆抗体。提出了三个目标。在 目的1我们提出产生CR-Kp特异性mAb的同种型转换变体，并研究CR-Kp特异性mAb的相关性。 体内Fc γ R结合。在目标2中，我们将鉴定先导单抗的表位，并鉴定最佳同种型。 候选mAb的保护效力。我们还将测试CR-Kp特异性mAb的组合， 用抗生素进行最佳保护最后，在目标3中，我们将使用鼠肠道定殖模型， 研究是否可以通过CPS治疗来预防在定殖小鼠中的寄生虫诱导的传播- 特异性mAb。

Carbapenem resistant Klebsiella pneumoniae (CR-Kp) bacteria are the most common gram-negative multidrug-resistant bacteria in US hospitals. CR-Kp cause predominantly pneumonia, sepsis and urinary tract infections and, in military personnel, complicated invasive wound infections as well. Most patients acquire this pathogen in health care associated settings. Soldiers are at risk because they commonly have prolonged stays in hospitals and rehabilitation centers when they recover from injuries they sustained in combat. Mortality of invasive CR-Kp infections is high and commonly over 50%. One problem is that most CR-Kp infections are diagnosed too late and empiric treatment with antibiotics like polymyxin is toxic and also compromised by emerging resistance even to these antibiotics. The goal of this application is to optimize two existing lead monoclonal antibodies (mAbs) that bind to the diverse polysaccharide capsule (CPS) of CR-Kp. Both clade 1 and clade 2 CPS-specific IgG mAbs are available and are expected to cover the majority of CR-Kp strains especially those that belong to the more virulent clade 2 of the clonal group CG258 group. Based on others and our published experience we propose several strategies to test these mAbs. Three aims are proposed. In Aim 1 we propose to generate isotype switch variants of CR-Kp specific mAbs and investigate relevance of FcɣR binding in vivo. In Aim 2 we will identify the epitopes of the lead mAbs, and identify the best isotypes of the candidate mAbs with respect to protective efficacy. We will also test combinations of CR-Kp specific mAbs with antibiotics for optimal protection. Finally, in Aim 3 we will use a murine gut colonization model to investigate if antibiotic-induced dissemination in colonized mice can be prevented by treatment with CPS- specific mAbs.