Serogrouping and subtyping of Legionella pneumophila with monoclonal antibodies

Abstract

Monoclonal antibodies directed against Legionella pneumophila serogroups 1 to 6 were produced by fusing splenocytes of BALB/c mice with the Sp 2/0-Ag14 or the NSO mouse myeloma cell lines. Specificity of these antibodies was determined by indirect fluorescent-antibody staining: 8 reacted with L. pneumophila serogroup 1 and, respectively, 13, 6, 6, 5, and 10 reacted with serogroups 2, 3, 4, 5, and 6; all except 5 were serogroup specific, and none presented cross-reactions with six other species of Legionellaceae. Serogroup determination of 35 isolates of L. pneumophila with seven selected monoclonal antibodies resulted in correct serogrouping in all instances; a pool of the same seven monoclonal antibodies stained intensely all strains of L. pneumophila without any staining of the other species of Legionellaceae. When 24 serogroup 1 isolates of L. pneumophila were stained with eight serogroup 1-specific monoclonal antibodies, the staining patterns could be clustered in five distinct groups. These hybridomas thus represent an unlimited source of standard reagent that could be used in the detection and serogrouping of L. pneumophila; differences in staining patterns could be used as epidemiological markers for these bacteria.

Comparison of Detection Methods for Legionella Species in Environmental Water by Colony Isolation, Fluorescent Antibody Staining, and Polymerase Chain Reaction

“…However, some of the anti-legionellae antibodies, even monoclonal ones, have the cross-reactivity to nonlegionellae such as Pseudomonas fluorescens, Bacteroides fragilis , or Xanthomonas sp. (2,6,11). Polyclonal antibodies-mixture for L. pneumophila serogroup 1 to 6 used in this survey reacted with several non-legionellae, but majority of their fluorescence were visibly distinguishable from the image of L. pneumophila under fluorescence microscopy, except E. coli GIFU 3160.…”

“…However, several specific antibodies including a monoclonal antibody for L. pneumophila to be cross-reactive with Pseudomonas spp. or Bacteroides fragilis (2,6,11). There may be a risk of overestimation of legionellae population in environmental microbial community.…”

Antigenic and genetic characterization of Leaionella Proteins: Contribution to taxonomy, diagnosis and pathogenesis

“…Using antibodies from panel I of the monoclonal antibodies reported by Joly et al (Joly et al 1983) two individual studies of a substantial number of patient and environmental isolates in Canada and France (Stout et al 1988, Dournon et al 1988) demonstrated a significant association between the source of an isolate and its monoclonal subtype. Patient isolates were closely associated with the Mab2 subtype in both reports, leading to the suggestion that this subtype could be a virulence marker.…”

“…Early epidemiological studies made evident that serotyping of L. pneumophila was not sdficiently discriminatory for epidemiological purposes. The use of monoclonal antibodies, raised against L. pneumophila SG 1, was established by three laboratories (Joly et al 1983, McKinney et al 1983, Watkins et al 1985, each contributing to an international panel of seven antibodies (Joly et al 1986) together identifjring ten distinct subtypes of L. pneumophila SG 1 by an indirect immunofluorescence assay. This panel was used for the investigation of several outbreaks, but evidence was accumulating that enhanced discrimination by addition of genetic methods was desirable (Pfaller et al 1989, Struelens et al 1992).…”

Cross-reactivity amongLegionellaspecies and serogroups

“…The use of a large number of antigens and antisera from related organisms presents difficulties due to the appearance of cross-reactions. This is especially important with organisms belonging to the family Legionellaceae that have been reported to share a variety of antigens with bacteria from different levels of relatedness (Joly & Kenny, 1982;Collins et al 1983a, b;Joly, Chen & Ramsay, 1983).…”