Abstract:In order to analyze the antigenicity of pili subunit of ETEC adhesin F41 and K99 and the possibility to use them as candidate in the subunit vaccine,two pairs of primers were designed according to the coding sequence of these adhesin genes and used for the amplification of the coding gene for these pili proteins. The full-length of the F41 and K99 fragments were cloned into the prolaryotic expression vector pET-28a and the expression of target protein in E.coli BL21 was determined by SDS-PAGE and Western blotting. It was found that the expressed F41 and K99 pili subunit proteins could react with antiserum against the single factor of F41 or K99 pili subunit proteins,thus proving the antigenicity of these proteins.