A MURINE MONOCLONAL-ANTIBODY DEFINES A UNIQUE EPITOPE SHARED BY KLEBSIELLA LIPOPOLYSACCHARIDES

A hybridoma secreting a monoclonal antibody (MAb) directed against Kle bsiella lipopolysaccharide (LPS) was derived from spleen cells of mice immunized with a smooth, nonencapsulated Klebsiella strain (Friedland er 201; serogroup 01). The MAb, called V/9-5 (immunoglobulin G2a), cro ss-reacted,vith LPS preparations produced from reference strains for t he Klebsiella 0 serogroups 01, 02ab, 02ac, 03, 04, 05, and 012. Furthe rmore, the MAb reacted with LPSs from serogroup reference strains 06/0 8, 09, and 011, which are regarded as being identical to 01, 02, and 0 4, respectively. When testing the supernatant of clinically isolated K lebsiella strains by means of an inhibition enzyme-linked immunosorben t assay, we found that 86 (92.4%) of 93 Klebsiella pneumoniae subsp. p neumoniae isolates and 26 (96.0%) of 25 K. oxytoca isolates harbored t he cross-reactive epitope. By contrast, two laboratory strains of K. p neumoniae subsp. rhinoscleromatis did not react with MAb V/9-5. The MA b proved to be specific for the genus Klebsiella, since it did not rea ct with any of a total of 73 strains belonging to other gram-negative bacterial genera. In conjunction with other LPS-specific MAbs, MAb V/9 -5 might become a useful reagent for rapid identification of klebsiell ae in clinical specimens. Furthermore, the epitope recognized by MAb V /9-5 might serve as a target epitope for the production of human MAbs for immunotherapeutic purposes.