Harnessing Antibody Responses to Prevent and Treat Urinary Tract Infections

摘要 尿路感染(UTIs)每年影响美国1500万女性，尿路感染的治疗是 由于抗生素耐药率高，变得更加困难。此外，尿路感染具有很高的重复性。在20之间 40%的尿路感染发作之后是复发性尿路感染(RUTI)，一些妇女遭受的尿路感染多达6或 每年有更多的复发。尿路致病性大肠杆菌(UPEC)是尿路感染的主要病原体。 UPEC分离株的抗生素耐药性正在上升，超广谱β-内酰胺酶的出现 产生氟喹诺酮耐药菌株是一个严重的公共卫生问题。类型1菌毛，尖端带有 甘露糖结合的FimH粘附素已被证明在膀胱定植和尿路感染发病机制中起重要作用 在多个老鼠模型中。FimH介导与衬里膀胱表面的甘露糖化尿板结合 促进膀胱细胞的定植和侵袭，在那里它们迅速复制到细胞内细菌 保护UPEC免受免疫细胞和抗生素侵害的社区。此外，FimH还促进了 UPEC在GIT中建立一个储存库，从那里他们可以通过从尿道周上升来播种尿路感染 进入膀胱的区域。虽然UPEC在基因上是可变的，但FimH是核心大肠杆菌基因组的一部分，尽管 已发现罕见的菌株存在1型操纵子突变。针对FimH的免疫接种可预防 UPEC UTI在小鼠和猴子膀胱炎模型中的应用和基于FimH的疫苗已被FDA允许用于 多药耐药UPEC患者。在动物模型中，保护是由抗体介导的，如FimH- 在受保护动物的尿液中发现了特定的免疫球蛋白抗体，可以通过被动的方式预防尿路感染。 调职。有趣的是，在有症状的尿路感染时，肠道中UPEC的丰度增加，这表明 肠道定植是Ruti循环中的关键步骤。此外，这项提案中的研究表明，诱导一种粘膜 针对FimH的抗体反应可以减少UPEC在肠道的定植。根据这些发现，这项建议 解决了抗FimH诱导的抗体可以通过两种不同的机制对抗Ruti的假设：i) 防止UPEC与尿路上皮结合；以及ii)干扰UPEC对GIT的定植，从而 降低UPEC进入尿路的可能性。这项提案的目的是：i)确定 粘膜接种FimCH如何减少UPEC肠道定植(目标1)；II)开发疫苗诱导的B 分离抗FimH的单抗并确定其表位特异性的细胞反应(目标2)； 和iii)将这些单抗用于git定植和膀胱炎的小鼠模型，以阐明 保护(目标3)。该研究计划将揭开抗FimH抗体可能发挥作用的机制 通过直接阻断膀胱结合和间接干扰UPEC GIT定植来预防尿路感染。 这些结果将为影响数百万尿路感染患者的尿路病原体的合理靶向提供信息。在……里面 此外，我们的方法能够快速产生可用于治疗的抗UPEC人源单抗 和诊断学。

SUMMARY Urinary tract infections (UTIs) affect 15 million women in the United States every year and treatment for UTIs is becoming more difficult due to high rates of antibiotic resistance. Further, UTIs are highly recurrent. Between 20 and 40% of UTI episodes are followed by recurrent UTIs (rUTIs), with some women suffering as many as 6 or more recurrences per year. Uropathogenic Escherichia coli (UPEC) is the major causative agent of UTIs. Antibiotic resistance within UPEC isolates is rising, and the emergence of extended-spectrum beta-lactamase producing and fluoroquinolone resistant strains is a serious public health concern. Type 1 pili, tipped with the mannose binding FimH adhesin have been shown to be essential for bladder colonization and UTI pathogenesis in multiple mouse models. FimH mediates binding to mannosylated uroplakins lining the bladder surface to facilitate colonization and invasion into bladder cells where they rapidly replicate into intracellular bacterial communities that protect UPEC from immune cells and antibiotics. In addition, FimH facilitates the ability of UPEC to establish a reservoir in the GIT, from where they can seed UTIs by ascending from the periurethral area into the bladder. While UPEC are genetically variable, FimH is part of the core E. coli genome, although rare strains have been found with mutations in the type 1 operon. Immunization against FimH protects against UPEC UTI in murine and monkey cystitis models and a FimH-based vaccine has been allowed by the FDA for patients suffering from multi-drug resistant UPEC. In animal models, protection is antibody-mediated, as FimH- specific IgG antibodies are found in the urine from protected animals and can protect from UTI through passive transfer. Intriguingly, UPEC abundance in the gut is increased at the time of symptomatic UTI, suggesting that gut colonization is a key step in the rUTI cycle. Additionally, studies in this proposal show that eliciting a mucosal antibody response against FimH can reduce UPEC colonization of the gut. In light of these findings, this proposal addresses the hypothesis that anti-FimH induced antibodies can combat rUTI by two distinct mechanisms: i) prevention of UPEC binding to the uroepithelium; and ii) interference with UPEC colonization of the GIT, thereby lowering the likelihood of UPEC introduction into the urinary tract. The aims of this proposal are to: i) determine how mucosal vaccination against FimCH reduces UPEC gut colonization (Aim 1); ii) exploit vaccine induced B cell responses to isolate monoclonal antibodies (mAbs) to FimH and determine their epitope specificity (Aim 2); and iii) use these mAbs in mouse models of GIT colonization and cystitis in order to elucidate mechanisms of protection (Aim 3). The research plan will unravel the mechanisms by which anti-FimH antibodies may function to prevent UTIs by directly blocking bladder binding and indirectly by interfering with UPEC GIT colonization. These results will inform the rational targeting of the uropathogens that affect millions of people with rUTIs. In addition, our approach enables the rapid generation of anti-UPEC human mAbs that can be used for therapeutics and diagnostics.