BINDING-STUDIES OF A MONOCLONAL-ANTIBODY SPECIFIC FOR 3-DEOXY-D-MANNO-OCTULOSONIC ACID WITH A PANEL OF KLEBSIELLA-PNEUMONIAE LIPOPOLYSACCHARIDES REPRESENTING ALL OF THE O-SEROTYPES

A monoclonal antibody (MAb) raised against Salmonella minnesota R595 a nd specific for alpha-3 deoxy-D-manno-octulosonic acid (alpha-Kdo) of the inner core was tested for binding to lipopoIysaccharides (LPS) of Klebsiella pneumoniae. The MAb was tested in several assay systems (en zyme-linked immunosorbent assay, passive hemolysis, and inhibition of passive hemolysis) with a large panel (n = 23) of K. pneumoniae LPS re presenting all nine currently known O serotypes. MAb 20 shelved reacti vity with almost all O serotypes of K. pneumoniae LPS, and this reacti vity could be inhibited by synthetic Kdo. This suggests an epitope in the cores of these Klebsiella LPS much like that in the inner core of LPS of S. minnesota. Large differences in reactivity between LPS of di fferent strains belonging to the same O serotype were observed, After sodium dodecyl sulfate-polyacrylamide gel electrophoresis of LPS follo wed by immunoblotting, reactivity of MAb 20 was observed only with the fast-moving fraction possibly representing the nonsubstituted core. N o binding was seen with the high-molecular-weight fraction that contai ned core material substituted with several units of O-antigen building blocks. The chemical basis for these differences in reactivity remain s to be established. As far as we know, this is the first report conta ining comprehensive immunochemical data on the LPS core of K. pneumoni ae.