title: Genus-specific epitope on the 60-kilodalton Legionella heat shock protein recognized by a monoclonal antibody.
abstract: A monoclonal antibody (MAb) immunoglobulin G2a (2125) was produced against a 60-kDa Legionella heat shock protein (HSP), recognizing a unique epitope common to all species of the genus Legionella. The antibody reacted in the immunoblot with 59 Legionella species and serogroups that were tested and showed no cross-reactivity with other bacteria, including Acinetobacter spp., Bordetella spp., Pseudomonas spp., Mycobacterium spp., and Escherichia coli. Two other MAbs (2122 and 2130) reacted with the 60-kDa Legionella protein as well but showed different cross-reactivities with other gram-negative bacteria in the same molecular mass range. The genus-specific MAb 2125 as well as the cross-reacting MAbs 2122 and 2130 were shown to be reactive with the expressed protein of the cloned gene of the 60-kDa HSP of Legionella micdadei and Legionella pneumophila. These antibodies demonstrate that Legionella-specific and nonspecific epitopes are present on this protein. A sandwich enzyme-linked immunosorbent assay (ELISA) in which the genus-specific MAb is used both as a capture antibody and as a biotinylated second antibody has been established. With this test it is possible to detect Legionella whole cells, sonicated cells, and cell fractions containing the 60-kDa HSP. The main part of the 60-kDa HSP is found in the cytoplasmic fraction. The sandwich ELISA can be used to demonstrate the increased expression of the 60-kDa protein in Legionella cells following heat shock as well as marked differences in the detection of the 60-kDa HSP on whole cells of different Legionella strains. The high specificity and sensitivity of the sandwich ELISA for sonicated cells might be very useful to screen on a genus level for Legionella cells or the 60-kDa antigen in environmental isolates or body fluids of patients.
authors.affiliation: Institute of Medical Microbiology, Hannover Medical School, Federal Republic of Germany.
authors.forename: I
authors.initials: I
authors.lastname: Steinmetz
authors.forename: C
authors.initials: C
authors.lastname: Rheinheimer
authors.forename: I
authors.initials: I
authors.lastname: Hübner
authors.forename: D
authors.initials: D
authors.lastname: Bitter-Suermann
mesh_terms: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007875:Legionella / Q000276:immunology* / Q000302:isolation & purification; D007876:Legionellosis / Q000175:diagnosis; D008970:Molecular Weight; D013045:Species Specificity
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D000939:Epitopes; D006360:Heat-Shock Proteins