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Fu L.,National Key Laboratory of Agricultural Microbiology | Fu L.,Huazhong Agricultural University | Zhao J.,Huazhong Agricultural University | Zhao J.,Key Laboratory of Development of Veterinary Diagnostic Products | And 15 more authors.
Microbes and Infection | Year: 2016

IgA1 protease of Streptococcus suis serotype 2 (SS2) has been proven to be relative with virulence and immunogenicity, however, its protective efficacy remained to be evaluated. The present study found evidence that immunization with purified recombinant IgA1 protease (600-1926aa) could induce high IgG antibody titers and could confer complete protection against a challenge with a lethal dose of SS2 in a mouse model. In addition, our findings confirmed that the IgA1 protease distributes on the surface of SS2. Therefore, the present study identified the virulence-associated protein, IgA1 protease, as a novel surface protective antigen of SS2. © 2016 Institut Pasteur.

Gong R.,National Key Laboratory of Agricultural Microbiology | Hu C.,National Key Laboratory of Agricultural Microbiology | Xu H.,National Key Laboratory of Agricultural Microbiology | Guo A.,National Key Laboratory of Agricultural Microbiology | And 5 more authors.
Clinical and Vaccine Immunology | Year: 2010

The present study evaluated the potential of recombinant binding region A of clumping factor A (rClfA-A) to be an effective component of a vaccine against mastitis induced by Staphylococcus aureus in the mouse. rClfA-A and inactivated S. aureus were each emulsified in Freund's adjuvant, mineral oil adjuvant, and Seppic adjuvant; phosphate-buffered saline was used as a control. Seven groups of 12 mice each were immunized intraperitoneally three times at 2-week intervals. The titers of IgG and subtypes thereof (IgG1 and IgG2a) in the rClfA-A-immunized group were more than 1,000-fold higher than those in the killed-bacteria-immunized group (P < 0.01). Of the three adjuvants used, mineral oil adjuvant induced the highest antibody levels for both antigens (P < 0.001). Furthermore, the anti-rClfA-A antibody capacities for bacterial adhesion and opsonizing phagocytosis were significantly greater in the rClfA-A-immunized group than in the killed-bacteria-immunized group (P < 0.05). Lactating mice immunized with either rClfA-A or inactivated vaccine were challenged with S. aureus via the intramammary route. The numbers of bacteria recovered from the murine mammary glands 24 h after inoculation were significantly lower in the rClfA-A group than in the killed-bacteria-immunized group (P < 0.001). Histologic examination of the mammary glands showed that rClfA-A immunization effectively preserved tissue integrity. Thus, rClfA-A emulsified in an oil adjuvant provides strong immune protection against S. aureus-induced mastitis in the mouse. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Chen B.,National Key Laboratory of Agricultural Microbiology | Chen B.,Huazhong Agricultural University | Zhang A.,National Key Laboratory of Agricultural Microbiology | Zhang A.,Huazhong Agricultural University | And 6 more authors.
Journal of Proteome Research | Year: 2011

Protein-protein interactions between bacteria and their hosts are responsible for all types of infection processes. The investigation of the bacteria-host crosstalk can provide a comprehensive understanding of the pathogenesis of bacterial disease. Despite scattered efforts in this field, a systematic identification of interactions between host and bacterial proteins remains unavailable. Here, we develop ACSP (affinity chromatography-based surface proteomics), which combines affinity chromatography and shotgun proteomics (LC-MS/MS), to investigate the interactions on a large-scale. Using ACSP, the potential surface interacting proteins (SIPs) of Streptococcus suis serotype 2 (SS2) were captured by the chromatographic resin, which was immobilized with the native surface molecules of Hep-2 cells. And then 40 potential SIPs were identified from the preys by LC-MS/MS, including 3 SIPs that have been previously reported in the literature. We selected 8 important SIPs and confirmed their ability to adhere to Hep-2 cells. Additionally, 3 newly identified SIPs, or their polyclonal antibodies, were found to significantly inhibit the adherence of SS2 to Hep-2 cells, indicating their essential role in the interaction between SS2 and Hep-2 cells. Using this example, we show that ACSP represents a new valuable tool for investigating the bacteria-host interactions. © 2011 American Chemical Society.

PubMed | Huazhong Agricultural University and National Key Laboratory of Agricultural Microbiology
Type: Journal Article | Journal: Microbiology and immunology | Year: 2016

Streptococcus suis infection induces formation of neutrophil extracellular traps (NETs) in vitro; however, the contribution of NETs-mediated killing to the pathogenesis of S. suis in vivo is yet to be elicited. The findings of the present study indicated that extracellular DNA fiber can be induced in a murine model in response to S. suis infection. A nuclease that destroys their structure was used to evaluate the role of NETs on S. suis infection. Treatment with nuclease resulted in a greater bacteria load and higher serum TNF- concentrations in response to S. suis infection, indicating that NETs structure played an essential role in S. suis clearance and inflammation. Furthermore, nuclease treatment resulted in more severe clinical signs during and higher mortality from S. suis infection. These findings indicated that NETs structure contributes to protection against S. suis infection.

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