Characterization Of Pathogenicity Roles Of Erysipelothrix Rhusiopathiae Molecules(GAPDH Et Al),and Verification Of DNA Polymerase ? As Diagnostic Marker

Erysipelothrix rhusiopathiae is the causative agent of animal erysipelas and human erysipeloid.Swine erysipelas is the most economically significant.The adhesion of E.rhusiopathiae to endothelial cells is suggested to be a crucial event in the initiation of E.rhusiopathiae infection.However,virulence factors and the mechanism by which E.rhusiopathiae initiates disease processes are not clearly understood.In this study,we characterized pathogenicity phenotypes of E.rhusiopathiae and compared the difference among srains with different virulence.Then we evaluated the ability of 5 E.rhusiopathiae surface proteins to act as a virulence factor.We evaluated the potential of the 5recombinant E.rhusiopathiae surface proteins to act protective antigen.Based our data,We developed or improved methods to differentiate E.rhusiopathiae vaccine strains and wild type strains.It was found that E.rhusiopathiae could adhere to pig endothelial cells and high virulent stain has higher adhesion activity.E.rhusiopathiae exhibited no direct cytotoxicity to pig endothelial cells.E.rhusiopathiae could exploit host plasminogen and fibronectin,and high virulent strains exhibit higher recruitment activity.High virulent strains exhibited stronger resistance activity to blood bactericidal.The dominant immune response of E.rhusiopathiae high virulent strain exhibited Th2 type.In this study,we cloned,expressed,and purified 5 E.rhusiopathiae proteins: Spa A,Cbp B,GAPDH,HP0728,HP1472.It was found that all five proteins localized on cell surface of E.rhusiopathiae.Spa A,Cbp B,GAPDH,HP1472 could acted as adhesins in E.rhusiopathiae adhesion to pig endothelial cells.Spa A,Cbp B,GAPDH,HP0728 could act as receptors in E.rhusiopathiae recruitment of host plasminogen and fibronectin.It was found that Spa A,Cbp B,GAPDH was protective antigen of E.rhusiopathiae.Immunization of recombinant proteins of HP0728 and HP1472 could not provided protection.Anti-r GAPDH serum could decrease adhesion rate E.rhusiopathiae adhesion to pig endothelial cells,increase blood bactericidal to E.rhusiopathiae,but could not decreased plasminogen and fibronectin recruitment of E.rhusiopathiae.Anti-r GAPDH serum could also bind to Streptococcus suis cells and Pasteurella multocida cells,whereas immunization of recombinant E.rhusiopathiae GAPDH failed to protect mice from challenge of the 2 pathogenic bacteria.Base on our data,we modified a SNP based PCR to differentiated Chinese E.rhusiopathiae vaccine strains and wild type strains.We also developed a duplex PCR duplex PCR for rapid detection and differentiation of E.rhusiopathiae vaccine strains and wild type strains.In conclusion,in this study we first time in the world demonstrated E.rhusiopathiae has no direct injury to pig endothelial cells,first time in the world determined E.rhusiopathiae's immune response type,first time in the world reported the plasminogen exploitation phenotype of E.rhusiopathiae and found several potential receptor,first time in the world provided a study demonstrating that a moonlighting protein plays a role in pathogenesis of E.rhusiopathiae infections,first time in the world reported GAPDH as a protective for E.rhusiopathiae,first time in the world developed a duplex PCR method to differentiate E.rhusiopathiae vaccine strains and wild type strains.