Molecular Cloning and Expression of Salmonella typhi Ragellin : Characterization of 52 kDa Specific Antigen of S. typhi

We previously reported monoclonal antibodies (MAbs) speclftc to S. typItI 52 kOa antigen which do not cross react with related protein antigens from 11 :..acterla causing enteric feyer and enteric feyer-llke Illness. Using the combination of these specHlc MAbs and recombinant DNA technology. expression plasmlds containing the antigen gene producing substantial amount of the S. typhl protein antigen have been established. Plasmid pSKM-T7 containing the specific 52 kOa antigen gene was cloned and the antigen expressed was detectable by immunoblottlng using specHlc mAbs. The complete nucleotide sequence of this gene was compared with other bacterial sequences and found to be highly homologous with the flagellin gene H 1 -d of S. muenchen except in the hypervarlable region In the central portion. The specific 52 kDa antigen of S. typhl detected by our MAbs is thus a flagellin.