HtrA is important for stress resistance and virulence in haemophilus parasuis

Luhua Zhang, Ying Li, Yiping Wen, Gee W. Lau, Xiaobo Huang, Rui Wu, Qigui Yan, Yong Huang, Qin Zhao, Xiaoping Ma, Xintian Wen, Sanjie Caoa

Research output: Contribution to journalArticlepeer-review


Haemophilus parasuis is an opportunistic pathogen that causes Glässer's disease in swine, with polyserositis, meningitis, and arthritis. The high-temperature requirement A (HtrA)-like protease, which is involved in protein quality control, has been reported to be a virulence factor in many pathogens. In this study, we showed that HtrA of H. parasuis (HpHtrA) exhibited both chaperone and protease activities. Finally, nickel import ATP-binding protein (NikE), periplasmic dipeptide transport protein (DppA), and outer membrane protein A (OmpA) were identified as proteolytic substrates for HpHtrA. The protease activity reached its maximum at 40°C in a time-dependent manner. Disruption of the htrA gene from strain SC1401 affected tolerance to temperature stress and resistance to complement-mediated killing. Furthermore, increased autoagglutination and biofilm formation were detected in the htrA mutant. In addition, the htrA mutant was significantly attenuated in virulence in the murine model of infection. Together, these data demonstrate that HpHtrA plays an important role in the virulence of H. parasuis.

Original languageEnglish (US)
Pages (from-to)2209-2219
Number of pages11
JournalInfection and immunity
Issue number8
StatePublished - 2016

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases


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