Recombinant Fc fusions for treatment of uropathogenic E. coli

尿路感染（UTI）是最常见的细菌感染之一，影响1.5亿 全世界每年。在美国，社区获得性尿路感染每年约有1100万例 每年花费美国公共卫生预算50亿美元。尿路致病性大肠杆菌（UPEC）占 高达80%的UTI。虽然目前用抗生素治疗UTI，但多药耐药的频率是 越来越多，预示着无法治疗的尿路感染的未来。抗生素的一种有希望的替代方法是直接靶向 细菌毒力因子是细菌粘附和侵入尿路上皮细胞的关键。这些 毒力因子包括细菌粘附素FimH，由大多数尿路致病性大肠杆菌表达。大肠杆菌菌株。 FimH结合到一个特定的糖型，寡甘露糖-3，由一个丰富的膜糖蛋白携带， 尿路上皮细胞 我们已经产生了针对FimH的重组蛋白。它是人类蛋白质的分子融合体， 二肽基肽酶4（DPP 4）与IgG 1 Fc（DPP 4-Fc），携带8个含甘露糖的N-聚糖，并结合 以甘露糖特异性的方式与FimH结合。我们已经证明，DPP 4-Fc促进了对尿路致病性大肠杆菌的杀伤。 大肠杆菌补体。本研究项目的目的是证明DPP 4-Fc促进细胞凋亡的能力。 补体在耐药尿路致病性E.大肠杆菌，从而导致增加 通过补体和多形核细胞（PMN）杀死细菌。 我们将产生三种新的DPP 4-Fc变体，每个单体携带不同数量的N-聚糖， 不同的糖型我们将修饰DPP 4-Fc的Fc以改善C1 q结合，从而增加C1 q的活化。 经典的补体途径修饰将包括点突变和IgG 1 Fc替换为 IgG3 Fc.我们还将产生阴性对照DPP 4-Fc，其中Fc含有两个点突变， 消除C1 q结合，因此没有调理活性。我们将测试所有这些新的DPP 4-Fc变体的 能够：i）结合致泌尿道疾病的大肠杆菌、肠杆菌和肺炎克雷伯氏菌菌株，ii）抑制细菌 附着于尿路上皮细胞，iii）促进血清介导的细菌杀伤和iv）促进调理吞噬作用 细菌。 我们期望DPP 4-Fc可以发展成为一种新的治疗尿路致病性大肠杆菌的药物。大肠杆菌，肠杆菌 和克雷伯氏菌感染。未来的研究项目将在动物模型中测试这些分子的活性， 后来在人体临床试验中。

Urinary tract infections (UTIs) are among the most common bacterial infections, affecting 150 million people worldwide each year. In the USA, community-acquired UTIs account for about 11 million cases each year that cost the U.S. public health budget $5 billion annually. Uropathogenic Escherichia coli (UPEC) accounts for up to 80% of UTIs. While UTIs are currently treated with antibiotics, the frequency of multi-drug resistance is increasing, portending a future of untreatable UTIs. A promising alternative to antibiotics is to directly target bacterial virulence factors that are critical for bacterial adhesion to and invasion of uroepithelial cells. These virulence factors include the bacterial adhesin FimH, expressed by the majority of uropathogenic E. coli strains. FimH binds to a specific glycoform, oligomannose-3, carried by an abundant membrane glycoprotein on uroepithelial cells. We have produced a recombinant protein targeting FimH. It is a molecular fusion of human protein, dipeptidyl peptidase 4 (DPP4) with IgG1 Fc (DPP4-Fc), carries eight mannose-containing N-glycans and binds in a mannose-specific manner to FimH. We have shown that that DPP4-Fc promotes killing of uropathogenic E. coli by complement. The purpose of this research project is to demonstrate the ability of DPP4-Fc to promote activation of complement on the surface of antibiotic-resistant uropathogenic E. coli thereby leading to increased bacterial killing by complement and polymorphonuclear cells (PMNs). We will produce three new variants of DPP4-Fc carrying different numbers of N-glycans per monomer and different glycoforms. We will modify the Fc of DPP4-Fc to improve C1q binding and thus increase activation of the classical complement pathway. Modifications will include point mutations and replacement of IgG1 Fc with IgG3 Fc. We will also produce a negative control DPP4-Fc in which the Fc contains two point mutations that abrogate C1q binding and thus has no opsonizing activity. We will test all these new DPP4-Fc variants for their ability to: i) bind to uropathogenic E.coli, Enterobacter and Klebsiella pneumonia strains, ii) inhibit bacterial attachment to urothelial cells, iii) promote serum mediated killing of bacteria and iv) promote opsonophagocytosis of bacteria. We expect that DPP4-Fc can be developed into a novel treatment for uropathogenic E. coli, Enterobacter and Klebsiella infections. Future research projects will test the activity of these molecules in animal models and later in human clinical trials.