Isolation and characterization of a lipopolysaccharide mutant of Legionella pneumophila.
A mutant unable to bind a monoclonal antibody (mAb 1E6) directed against serogroup 1 lipopolysaccharide (LPS) was isolated from L. pneumophila strain Philadelphia-1. SDS-PAGE analysis of isolated LPS from the mutant and wild type revealed that there were no obvious structural differences between the two LPS. The results from Western-blot experiments showed that the mutant LPS was unable to bind mAb 1E6 but retained the ability to bind polyclonal serogroup 1 antibodies. Loss of the LPS epitope recognized by mAb 1E6 did not alter the ability of the mutant to multiply in human monocyte-like U937 cells. Also, the mutant, like wild type, was resistant to killing by normal human serum. These results show that a minor change in the antigenic composition of serogroup 1 LPS has no effect on the virulence properties of strain Philadelphia-1. Additionally, this mutant may be useful for molecular genetic analysis of serogroup 1 LPS biosynthesis and assembly.
Mintz
C S
CS
Department of Microbiology and Immunology, University of Miami School of Medicine, FL 33101.
Zou
C H
CH
D001770:Blood Bactericidal Activity; D002460:Cell Line; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D006801:Humans; D016952:Legionella pneumophila / Q000235:genetics* / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification; D008070:Lipopolysaccharides / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D009000:Monocytes / Q000166:cytology; D009154:Mutation; D012703:Serotyping
D000939:Epitopes; D008070:Lipopolysaccharides