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

A hybridoma secreting a monoclonal antibody (MAb) directed against Klebsiella lipopolysaccharide (LPS) was derived from spleen cells of mice immunized with a smooth, nonencapsulated Klebsiella strain (Friedlander 201; serogroup 01). The MAb, called V/9-5 (immunoglobulin G2a), cross-reacted,vith LPS preparations produced from reference strains for the Klebsiella 0 serogroups 01, 02ab, 02ac, 03, 04, 05, and 012. Furthermore, the MAb reacted with LPSs from serogroup reference strains 06/08, 09, and 011, which are regarded as being identical to 01, 02, and 04, respectively. When testing the supernatant of clinically isolated Klebsiella strains by means of an inhibition enzyme-linked immunosorbent assay, we found that 86 (92.4%) of 93 Klebsiella pneumoniae subsp. pneumoniae isolates and 26 (96.0%) of 25 K. oxytoca isolates harbored the cross-reactive epitope. By contrast, two laboratory strains of K. pneumoniae subsp. rhinoscleromatis did not react with MAb V/9-5. The MAb proved to be specific for the genus Klebsiella, since it did not react 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 klebsiellae 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.