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Clinical and Vaccine Immunology, June 2009, p. 835-843, Vol. 16, No. 6
1071-412X/09/$08.00+0 doi:10.1128/CVI.00021-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Pgp3 Antibody Enzyme-Linked Immunosorbent Assay, a Sensitive and Specific Assay for Seroepidemiological Analysis of Chlamydia trachomatis Infection
Gillian S. Wills,1,
Patrick J. Horner,2,
Rosy Reynolds,3
Anne M. Johnson,4
David A. Muir,5
David W. Brown,6
Alan Winston,1
Andrew J. Broadbent,1
David Parker,7 and
Myra O. McClure1*
Jefferiss Trust Laboratories, Wright-Fleming Institute, Imperial College London,1 Research Department of Infection and Population Health, University College London,4 Department of Diagnostic Virology, St Mary's Hospital, Imperial College Healthcare NHS Trust,5 Health Protection Agency Centre for Infections, Colindale, London,6 Department of Social Medicine, University of Bristol,2 Department of Medical Microbiology, North Bristol NHS Trust, Bristol,3 Novel Consulting, Crown House, Home Gardens, Dartford, United Kingdom7
Received 6 January 2009/ Returned for modification 23 February 2009/ Accepted 31 March 2009
Understanding of the burden of Chlamydia trachomatis infection and its clinical sequelae is hampered by the absence of accurate, well-characterized tests using serological methods to determine past exposure to infection. An "in-house" immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) based on the C. trachomatis-specific antigen Pgp3 was produced and evaluated against three commercial ELISAs derived from the major outer membrane protein: the Medac pELISA plus, the Savyon SeroCT-IgG ELISA, and the Ani Labsystems IgG enzyme immunoassay. Sensitivities and specificities were determined using sera from both male and female patients (n = 356) for whom C. trachomatis had been detected in the lower genital tract at least 1 month prior to the testing of the sample and from 722 Chlamydia-negative children aged 2 to 13 years. The Pgp3 ELISA was significantly more sensitive (57.9% [95% confidence interval {95% CI}, 52.7 to 62.9%]) than the Ani Labsystems (49.2% [95% CI, 44.0 to 54.3%]; P = 0.003), SeroCT (47.2% [95% CI, 42.1 to 52.4%]; P < 0.0005), and Medac (44.4% [95% CI, 39.3 to 49.6%]; P < 0.0005) ELISAs. The Pgp3, Ani Labsystems, and SeroCT assays, but not the Medac assay, had significantly higher sensitivity for female specimens than for male specimens (73.8 versus 44.2%, 59.8 versus 40.5%, 55.5 versus 40%, and 45.7 versus 43.7%, respectively). For female patients, the Pgp3 assay was 14.0% (95% CI, 5.5 to 22.5%) more sensitive than the next most sensitive ELISA, the Ani Labsystems assay (P = 0.001). There was no significant difference in specificity between the Pgp3 (97.6% [95% CI, 96.2 to 98.6%]), Ani Labsystems (99% [95% CI, 97.7 to 99.6%]), SeroCT (97.2% [95% CI, 95.7 to 98.2%]), and Medac (96% [95% CI, 94.3 to 97.2%]) ELISAs. None of the ELISAs showed evidence of cross-reactivity with antibodies to Chlamydia pneumoniae.
* Corresponding author. Mailing address: Jefferiss Trust Laboratories, Wright-Fleming Institute, Imperial College London, London W2 1PG, United Kingdom. Phone: 44-207-5943902. Fax: 44-207-5943906. E-mail: m.mcclure{at}imperial.ac.uk
Published ahead of print on 8 April 2009.
G.S.W. and P.J.H. contributed equally to this article.
Clinical and Vaccine Immunology, June 2009, p. 835-843, Vol. 16, No. 6
1071-412X/09/$08.00+0 doi:10.1128/CVI.00021-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
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