title: Development and evaluation of an enzyme-linked immunosorbent assay for the detection of antibodies to a common urogenital derivative of Chlamydia trachomatis plasmid-encoded PGP3.
abstract: Urogenital infection with Chlamydia trachomatis is the most commonly diagnosed sexually transmitted infection in the developed world. Accurate measurement and therefore understanding the seroprevalence of urogenital C. trachomatis infections requires a rigorously optimised and validated ELISA. Previous ELISAs based on the C. trachomatis plasmid-encoded protein, PGP3, have been described but lack standardisation and critical controls or use a less common PGP3 as the capture antigen.
  
  
  
  A sensitive and specific indirect ELISA was developed based on recombinant PGP3 derived from a urogenital strain of C. trachomatis, serovar E (pSW2), using a rigorous validation protocol. Serum samples were collected from 166 genitourinary medicine (GUM) clinic patients diagnosed as positive or negative for urogenital C. trachomatis infection by nucleic acid amplification testing (NAATs). Overall sensitivity and specificity compared to NAATs was 68.18% and 98.0%, respectively. Sensitivities for female and male samples were 71.93% and 64.15%, respectively. Comparison of samples from these patients diagnosed positive for C. trachomatis by NAAT and patients diagnosed negative by NAAT revealed statistical significance (p≤0.0001).
  
  
  
  We have developed and validated a sensitive and specific ELISA to detect anti-PGP3 antibodies as an indicator of past and current infection to C. trachomatis using PGP3 from a common urogenital strain. It is anticipated that this assay will be used for seroepidemiological analysis of urogenital C. trachomatis in populations.
authors.affiliation: Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, Hampshire, United Kingdom. Electronic address: cew1g13@soton.ac.uk.
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Winstanley
authors.affiliation: Department of Microbiology & Immunology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL, USA.
authors.forename: Kyle H
authors.initials: KH
authors.lastname: Ramsey
authors.affiliation: Public Health England Regional Microbiology Laboratory, Southampton General Hospital, Southampton, Hampshire, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Marsh
authors.affiliation: Molecular Microbiology Group, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, Hampshire, United Kingdom.
authors.forename: Ian N
authors.initials: IN
authors.lastname: Clarke
mesh_terms: D000906:Antibodies / Q000032:analysis* / Q000276:immunology; D000942:Antigens, Bacterial / Q000097:blood / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000097:blood / Q000235:genetics / Q000276:immunology*; D002690:Chlamydia Infections / Q000175:diagnosis / Q000276:immunology*; D002692:Chlamydia trachomatis / Q000276:immunology*; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D011994:Recombinant Proteins / Q000097:blood / Q000235:genetics / Q000276:immunology
chemical_list: D000906:Antibodies; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011994:Recombinant Proteins; C082169:pgp3 protein, Chlamydia
keywords: Antibody; Chlamydia infection; Chlamydia trachomatis; ELISA; Enzyme-linked immunosorbent assay; PGP3