Deletion of ssnA Attenuates the Pathogenicity of Streptococcus suis and Confers Protection against Serovar 2 Strain Challenge

作者：Li, Miao; Cai, Ru-Jian^*; Li, Chun-Ling^*; Song, Shuai; Li, Yan; Jiang, Zhi-Yong; Yang, Dong-Xia

来源：PLos One, 2017, 12(1): e0169791.

DOI：10.1371/journal.pone.0169791

• NEUTROPHIL EXTRACELLULAR TRAPS
• ZOONOTIC PATHOGEN
• MOUSE MODEL
• VIRULENCE
• SEROTYPE-2
• DNASE
• GENE
• IDENTIFICATION
• DEGRADATION
• PNEUMONIAE

Streptococcus suis serotype 2 (SS2) is a major porcine and human pathogen which causes arthritis, meningitis, and septicemia. Streptococcus suis nuclease A (SsnA) is a recently discovered deoxyribonuclease (DNase), which has been demonstrated to contribute to escape killing in neutrophil extracellular traps (NETs). To further determine the effects of ssnA on virulence, the ssnA deletion mutant (Delta ssnA) and its complemented strain (C-Delta ssnA) were constructed. The ability of Delta ssnA mutant to interact with human laryngeal epithelial cell (Hep-2) was evaluated and it exhibited dramatically decreased ability to adhere to and invade Hep-2 cells. This mutation was found to exhibit significant attenuation of virulence when evaluated in CD1 mice, suggesting ssnA plays a critical role in the pathogenesis of SS2. Finally, we found that immunization with the Delta ssnA mutant triggered both antibody responses and cell-mediated immunity, and conferred 80% protection against virulent SS2 challenge in mice. Taken together, our results suggest that Delta ssnA represents an attractive candidate for designing an attenuated live vaccine against SS2.

• 出版日期2017-1-12
• 单位广东省农业科学院