Identification, Characterization Of Epitope And Surface Molecular Binding Peptide From The Erysipelothrix Rhusiopthiae By Phage Display

Erysipelothrix rhusiopthiae (E.rhusiopathiae) is Gram-positive, rod-shaped, asporous bacteria that cause swine erysipelas. The objective of this study was to investigate characteristics of peptides and surface molecular binding peptides(SMBP) from E.rhusiopathiae by Phage Display.The E.rhusiopathiae polyantibodies were purified through the bacterium antigen adsorption combined with recombination protein A (SPA) of staphylococcus affinity chromatography from swine serum and were immunescreened against phage-displayed random dodecapeptide library (Ph.D.-12). After three rounds of biopanning,224phage clones were randomly selected and sequenced, there were total36mimotopes were obtained. Furthermore, E.rhusiopathiae were directly screened by phage-displayed random dodecapeptide library, after the same biopanning method,144phage clones were randomly selected and sequenced, there were total66SMBP were obtained.11mimotopes were positive by indirect ELISA, three of which had a little high reacted with BSA. The mimotope15(GPKSNNVGVTYS), had reactogenicity by western-blot which as the highest homology with SMBP (NLLGPHRISDME) and the most amount of homologus SMBP in all of the mimotopes by molecular recognition theory, may be the dominant epitope in E.rhusiopathiae. Moreover, there were26mimotopes’antisense peptide,8were positive by indirect ELISA, also had been found such relation with their homologus SMBP from the other35mimotopes, although the homology were not very high, the most positive mimotopes’antisense peptide had more than one homologus SMBP by this theory. Those mimotopes were blast in the NCBI, and we found that many of them were the surface proteins、Lipoproteins or glycoproteins of bacterium, especially to the gram-positive bacterium, they were participated in bacterium’s growth and metabolism、adapt for environment infection for host cell、anti-infection for phage, and so on. Therefore, the epitope analysis of E.rhusiopathiae can be more facilitated from those information, moreover, the mimotopes were found to be useful for developing broad spectrum vaccine of those bacterium.11of the E.rhusiopathiae SMBP were positive by indirect ELISA. We also found that9and2of the11positive SMBP could react to the7strain and2strain Streptococcus suis, respectively, two of them were the common positive SMBP for the three bacterium. These results indicated that there were some similar surface moleculars between E.rhusiopathiae and Streptococcus suis, however, the difference of SMBP at the homogeneous bacteria can apply to identify among different serotype. Form the NCBI, We also found that some of SMBP may be the surface receptor proteins of host cell such as neurocyte and immunocyte; some of them may be the enzymes which were secreted from host cell or bacteria itself; some of them may be the surface regulatory factors of host cell; others may be the outer membrane of phage. Hence, we deprived E.rhusiopathiae SMBP which indicated that the surface molecular of this bacteria may have the interaction with host and can analysis pathogenesis of the disease.We developed a method that identification the mimotope and the SMBP from E.rhusiopathiae by Phage Display to characterize the surface construction, immunity or virulence, at the same time this enables it to use to other bacterium especially to the identification serotype.