| Title | The type II histidine triad protein HtpsC facilitates invasion of epithelial cells by highly virulent Streptococcus suis serotype 2 |
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| Author | Yunjun Lu1†, Shu Li2†, Xiaodong Shen2, Yan Zhao2, Dongming Zhou3, Dan Hu3, Xushen Cai1, Lixia Lu1, Xiaohui Xiong1, Ming Li2*, and Min Cao1* |
| Address | 1College Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, Jiangsu, P. R. China, 2Department of Microbiology, College of Basic Medical Sciences, Army Medical University (Third Military Medical University), Key Laboratory of Microbial Engineering under the Educational Committee in Chongqing, Chongqing 400038, P. R. China, 3Center for Disease Control and Prevention for the Eastern Theater Command, Nanjing 210002, Jiangsu, P. R. China |
| Bibliography | Journal of Microbiology, 59(10),949-957, 2021, |
| DOI | 10.1007/s12275-021-1129-1 |
| Key Words | Streptococcus suis serotype 2, HtpsC, invasion, adhesion, epithelial cells |
| Abstract | Streptococcus suis serotype 2 (S. suis 2) is an important zoonotic pathogen that presents a significant threat both to pigs and to workers in the pork industry. The initial steps of S. suis 2 pathogenesis are unclear. In this study, we found that the type II histidine triad protein HtpsC from the highly virulent Chinese isolate 05ZYH33 is structurally similar to internalin A (InlA) from Listeria monocytogenes, which plays an important role in mediating listerial invasion of epithelial cells. To determine if HtpsC and InlA function similarly, an isogenic htpsC mutant (ΔhtpsC) was generated in S. suis by homologous recombination. The htpsC deletion strain exhibited a diminished ability to adhere to and invade epithelial cells from different sources. Double immunofluorescence microscopy also revealed reduced survival of the ΔhtpsC mutant after cocultivation with epithelium. Adhesion to epithelium and invasion by the wild type strain was inhibited by a monoclonal antibody against E-cadherin. In contrast, the htpsC-deficient mutant was unaffected by the same treatment, suggesting that E-cadherin is the host-cell receptor that interacts with HtpsC and facilitates bacterial internalization. Based on these results, we propose that HtpsC is involved in the process by which S. suis 2 penetrates host epithelial cells, and that this protein is an important virulence factor associated with cell adhesion and invasion. |