title: Identification and characterization of immunogenic proteins of mycoplasma genitalium.
abstract: Mycoplasma genitalium causes nonchlamydial nongonococcal urethritis. M. genitalium was detected by PCR in 17 urethral swabs obtained from 99 men with and without urethritis (J. S. Jensen, R. Orsum, B. Dohn, S. Uldum, A. M. Worm, and K. Lind, Genitourin. Med. 69:265-269, 1993), and later, four M. genitalium strains were isolated (J. S. Jensen, H. T. Hansen, and K. Lind, J. Clin. Microbiol. 34:286-291, 1996). The objective of this study was to characterize immunogenic proteins of M. genitalium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting by using a hyperimmune rabbit serum against M. genitalium G37, determine their identity by mass spectrometry, and develop an M. genitalium-specific enzyme-linked immunosorbent assay (ELISA) free from cross-reactivity with M. pneumoniae antibodies. Using recombinant fragments of the C-terminal part of MgPa (rMgPa), we developed a specific ELISA for detection of M. genitalium antibodies. This antigen did not bind M. pneumoniae antibodies. Using serum samples from the 99 men with and without urethritis, we found that 26 had immunoglobulin G (IgG) antibodies to M. genitalium. There was a strong statistically significant correlation between PCR and IgG antibodies to M. genitalium (odds ratio [OR], 5.9; 95% confidence interval [CI], 2.3 to 21.5; P = 0.002). Furthermore, men with recurrent urethritis were more likely to have antibodies to M. genitalium than were those without recurrent urethritis (OR, 4.0; 95% CI, 1.1 to 14.5; P = 0.0383) and they had significantly higher antibody titers. By use of the rMgPa ELISA, this study further substantiates the importance of M. genitalium as a cause of male urethritis.
authors.affiliation: Institute of Medical Microbiology and Immunology, The Bartholin Building, Aarhus University, DK-8000 Aarhus C, Denmark. hellef@medicro.au.dk
authors.forename: Helle Friis
authors.initials: HF
authors.lastname: Svenstrup
authors.forename: Jørgen Skov
authors.initials: JS
authors.lastname: Jensen
authors.forename: Kris
authors.initials: K
authors.lastname: Gevaert
authors.forename: Svend
authors.initials: S
authors.lastname: Birkelund
authors.forename: Gunna
authors.initials: G
authors.lastname: Christiansen
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000276:immunology*; D002692:Chlamydia trachomatis / Q000276:immunology; D003429:Cross Reactions; D003902:Detergents / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D045704:Mycoplasma genitalium / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D009177:Mycoplasma pneumoniae / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000737:chemistry; D016133:Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014526:Urethritis / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D003902:Detergents; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40