title: Molecular detection and seroepidemiology of the Chlamydia pneumoniae bacteriophage (PhiCpn1).
abstract: Recent whole-genome analysis has demonstrated limited genetic variation in Chlamydia pneumoniae, with one strain (AR39) containing a 4,524 nucleotide single-stranded DNA bacteriophage, PhiCpn1. Using PCR, reverse transcription (RT)-PCR, and Western blotting, we confirmed the presence and functional expression of PhiCpn1 in C. pneumoniae strain AR39 and its absence in strain CWL029. Six additional epidemiologically distinct clinical isolates of C. pneumoniae also did not contain PhiCpn1. We generated recombinant viral protein 1 (Vp1) from PhiCpn1 in Escherichia coli and showed that Vp1 antigen is highly immunogenic in mice and that murine antisera readily recognize native Vp1 from C. pneumoniae strain AR39 elementary bodies (EB). We developed an enzyme-linked immunosorbent assay (ELISA) to measure antibodies to recombinant Vp1 in human sera collected from 32 patients with abdominal aortic aneurysm (AAA) and 40 controls. Among the 72 subjects, 61 had C. pneumoniae EB antibodies shown by ELISA. Antibodies to Vp1 were found in 39 of the 61 (64%) seropositive individuals and were significantly correlated with AAA (adjusted odds ratio, 13.9; 95% confidence interval, 1.1 to 175). Our studies indicate that phage-containing strains of C. pneumoniae are uncommonly found by isolation but may commonly infect individuals with vascular disease.
authors.affiliation: University of British Columbia Centre for Disease Control, Vancouver, Canada.
authors.forename: Karuna P
authors.initials: KP
authors.lastname: Karunakaran
authors.forename: James F
authors.initials: JF
authors.lastname: Blanchard
authors.forename: Ausra
authors.initials: A
authors.lastname: Raudonikiene
authors.forename: Caixia
authors.initials: C
authors.lastname: Shen
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Murdin
authors.forename: Robert C
authors.initials: RC
authors.lastname: Brunham
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D017544:Aortic Aneurysm, Abdominal / Q000382:microbiology / Q000821:virology; D001435:Bacteriophages / Q000235:genetics* / Q000276:immunology; D023521:Chlamydophila Infections / Q000382:microbiology; D016993:Chlamydophila pneumoniae / Q000145:classification / Q000276:immunology / Q000821:virology*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D010940:Plant Proteins; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000276:immunology; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000907:Antibodies, Bacterial; D000914:Antibodies, Viral; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D015534:Trans-Activators; D014157:Transcription Factors