PRODUCTION OF MONOCLONAL-ANTIBODY DISCRIMINATING SEROLOGICAL DIFFERENCE IN ESCHERICHIA-COLI O9 AND O9A POLYSACCHARIDES

A monoclonal antibody (mAb) with a unique antigenic specificity agains t Escherichia coli O9 was produced, The O9a mAb was reactive with a pa rt of the strains in E. coli O9. The O9a mAb did not react with LPS fr om the E. coli O9 test strain Bi316-42, The distribution of the antige n defined by the O9a mAb in E. coli O9 was consistent with that off. c oli O9a present in E. coli O9 strains. The chemical structure of the r epeating unit of the O-specific polysaccharide detected by the mAb was demonstrated to be a mannotetraose by two-dimensional nuclear magneti c resonance spectroscopy. It was confirmed that the mAb recognized E. coli O9a serotype in E. coli O9 serotype strains, suggesting that E. c oli O9a serotype might be a dominant strain in E. coli O9.