Department of Infectious Diseases, MedImmune, LLC, Gaithersburg, MD 20878, USA.
J Exp Med. 2012 Jul 2;209(7):1273-87. doi: 10.1084/jem.20120033. Epub 2012 Jun 25.
Pseudomonas aeruginosa is a leading cause of hospital-associated infections in the seriously ill, and the primary agent of chronic lung infections in cystic fibrosis patients. A major obstacle to effective control of P. aeruginosa infections is its intrinsic resistance to most antibiotic classes, which results from chromosomally encoded drug-efflux systems and multiple acquired resistance mechanisms selected by years of aggressive antibiotic therapy. These factors demand new strategies and drugs to prevent and treat P. aeruginosa infections. Herein, we describe a monoclonal antibody (mAb) selection strategy on whole P. aeruginosa cells using single-chain variable fragment phage libraries derived from healthy individuals and patients convalescing from P. aeruginosa infections. This approach enabled identification of mAbs that bind three distinct epitopes on the product of the Psl. This exopolysaccharide is important for P. aeruginosa attachment to mammalian cells, and for the formation and maintenance of biofilms produced by nonmucoid and mucoid P. aeruginosa isolates. Functional screens revealed that mAbs to one epitope exhibit superior activity in opsonophagocytic killing and cell attachment assays, and confer significant protection in multiple animal models. Our results indicate that Psl is an accessible serotype-independent surface feature and promising novel protective antigen for preventing P. aeruginosa infections. Furthermore, our mAb discovery strategy holds promise for application to other bacterial pathogens.
铜绿假单胞菌是严重疾病患者医院相关感染的主要病原体，也是囊性纤维化患者慢性肺部感染的主要病原体。有效控制铜绿假单胞菌感染的主要障碍是其对大多数抗生素类别的固有耐药性，这是由染色体编码的药物外排系统和多年强化抗生素治疗选择的多种获得性耐药机制引起的。这些因素需要新的策略和药物来预防和治疗铜绿假单胞菌感染。在此，我们描述了一种使用源自健康个体和从铜绿假单胞菌感染中康复的患者的单链可变片段噬菌体文库对整个铜绿假单胞菌细胞进行单克隆抗体（mAb）选择的策略。这种方法能够鉴定出与 Psl 产物上三个不同表位结合的 mAbs。这种胞外多糖对于铜绿假单胞菌附着于哺乳动物细胞以及非粘液型和粘液型铜绿假单胞菌分离株产生的生物膜的形成和维持非常重要。功能筛选显示，针对一个表位的 mAbs 在调理吞噬杀伤和细胞附着试验中表现出优异的活性，并在多种动物模型中提供了显著的保护作用。我们的结果表明，Psl 是一种可及的、与血清型无关的表面特征，是预防铜绿假单胞菌感染的有前途的新型保护性抗原。此外，我们的 mAb 发现策略有望应用于其他细菌病原体。
