Identification and characterization of immunogenic proteins of mycoplasma genitalium.
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.
Svenstrup
Helle Friis
HF
Institute of Medical Microbiology and Immunology, The Bartholin Building, Aarhus University, DK-8000 Aarhus C, Denmark. hellef@medicro.au.dk
Jensen
Jørgen Skov
JS
Gevaert
Kris
K
Birkelund
Svend
S
Christiansen
Gunna
G
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
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D003902:Detergents; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40