Pro-inflammatory Mechnasiam Study Of Streptococcus Suis Serotype 2 Extracellular Proteins HP1856

Streptococcus suis type?Streptococcus suis 2,SS2?2 is an important pathogen threating the swine industry and is also an emerging zoonotic pathogens,According to the literature,it has resulted in more than two thousand worldwide people infected with the disease and even cause death seriously once in our country Jiangsu and Sichuan provinces broke out two large-scale pig streptococcus disease,and now is a tremendous threat to the aquaculture and the safety of human life.Streptococcus suis can cause pigs and people showed arthritis,endocarditis,meningitis and septicemia symptoms after infection,Streptococcus suis infection can cause the activation of host immune system,Leading to a host of inflammatory factors releasing large amounts to clear the pathogen,It helps the host to resist the invasion of S.suis,However,the excess immune response may result the host to produce septic shock.Studies have shown that there are some pro-inflammatory component may play an important role in the process of the host to produce sepsis.The study found a significant pro-inflammatory surface protein of Streptococcus suis type 2 and make this protein as a study object,further study the Specific mechanisms of the protein causes inflammation,To provide some evidence for control the wine disease caused by the Streptococcus suis.The object of this study is encoded by a gene SSU05₁856 and is a Streptococcus suis type 2 extracellular proteins naned HP 1856,Specific contents of this study are as follows:1)We expressed and purified the protein in vitro with the pET-28a plasmid vector;2)We carried out cell experiments in RAW264.7 cells after removing the protein endotoxin,This protein was found to stimulate RAW264.7 cells releasing a high levels of pro-inflammatory cytokines IL-lp,TNF-?,IFN-? and MCP1;3)We found that HP1856 inducing the RAW264.7 upregulate release TNF-? and IL-1? can be inhibited by the TLR4 specific antibodies and not be the TLR2 specific antibodies tested by TLR2?TLR4 antibody characteristics as well as TLR2?TLR4 gene deficient mice;Gene deletion mice speculate that upregulation of cytokines induced protein may be TLR4-dependent;4)And then we used the related signaling pathways inhibitor to verify signaling pathway intermediate molecule,The fluorescence quantitative results show that the HP1856 activate IL-1?,TNF-?,MCP1 and IFN-? may be mainly through PI3K and NF-?B;5)In order to study the function of the protein,We constructed an overexpression strain to make the gene overexpression,Deternination the growth curve of the overexpression strain showed that the overexpression strains and the parent strain 1s no significant difference in the growth rate;6)Then we evaluated the overexpression strain pro-inflammatory effects with RAW264.7 cellin vitro,the results showed that overexpression strain has a more obvious pro-inflarmatory effect relative to the parent strain,Tip overexpression strain expressing the protein may helps the host to produce a strong inflammatory response;7)Following we tested by a mice,the body blood volume results show that over-expression strains higher than the parent strain after the bacterial infection,this suggests that the presence of the protein causes the blood to clear the pathogens slower in the SS2 pathogenic process,and it may helps the host to produce more severe sepsis.In summary,the recombinant protein HP 1856 is a pro-inflammatory component having significant pro-inflammatory effect,and may plays a important role in the pathogenesis of Streptococcus suxs serotype 2,We hope to provide new ideas for the prevention of Streptococcus suls by study this pathogenic mechanism.