Schauer Kristina, Lehner Angelika, Dietrich Richard, Kleinsteuber Ina, Canals Rocío, Zurfluh Katrin, Weiner Kerstin, Märtlbauer Erwin
Department of Veterinary Science, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim, Germany
Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland.
Infect Immun. 2015 Mar;83(3):876-87. doi: 10.1128/IAI.02211-14. Epub 2014 Dec 22.
Cronobacter turicensis is an opportunistic foodborne pathogen that can cause a rare but sometimes lethal infection in neonates. Little is known about the virulence mechanisms and intracellular lifestyle of this pathogen. In this study, we developed an IgG monoclonal antibody (MAb; MAb 2G4) that specifically recognizes the O1 antigen of C. turicensis cells. The antilipopolysaccharide antibody bound predominantly monovalently to the O antigen and reduced bacterial growth without causing cell agglutination. Furthermore, binding of the antibody to the O1 antigen of C. turicensis cells caused a significant reduction of the membrane potential which is required to energize flagellar rotation, accompanied by a decreased flagellum-based motility. These results indicate that binding of IgG to the O antigen of C. turicensis causes a direct antimicrobial effect. In addition, this feature of the antibody enabled new insight into the pathogenicity of C. turicensis. In a tissue culture infection model, pretreatment of C. turicensis with MAb 2G4 showed no difference in adhesion to human epithelial cells, whereas invasion of bacteria into Caco-2 cells was significantly inhibited.
苏黎世克罗诺杆菌是一种机会性食源性病原体，可在新生儿中引起罕见但有时致命的感染。关于这种病原体的毒力机制和细胞内生存方式知之甚少。在本研究中，我们开发了一种IgG单克隆抗体（MAb；MAb 2G4），该抗体可特异性识别苏黎世克罗诺杆菌细胞的O1抗原。抗脂多糖抗体主要以单价形式结合到O抗原上，并在不引起细胞凝集的情况下抑制细菌生长。此外，该抗体与苏黎世克罗诺杆菌细胞的O1抗原结合导致膜电位显著降低，而膜电位是鞭毛旋转所需的能量，同时基于鞭毛的运动性也降低。这些结果表明，IgG与苏黎世克罗诺杆菌的O抗原结合会产生直接的抗菌作用。此外，该抗体的这一特性为深入了解苏黎世克罗诺杆菌的致病性提供了新的视角。在组织培养感染模型中，用MAb 2G4预处理苏黎世克罗诺杆菌后，其对人上皮细胞的黏附没有差异，而细菌对Caco-2细胞的侵袭则受到显著抑制。
