title: Tobacco smoke induces persistent infection of Chlamydophila pneumoniae in HEp-2 cells.
abstract: We examined tobacco smoke exposure and its effect on the life cycle of Chlamydophila pneumoniae (C. pneumoniae) in HEp-2, a human respiratory epithelial cell line. Using noncytotoxic concentrations of smoke medium, chlamydiae were grown in tissue culture and infectious particles were quantitated indirectly by immunocytometry of infected indicator cells. Chlamydial genome copy number was assessed with real-time polymerase chain reaction, and ultrastructure was examined by transmission electron microscopy. There was a significant reduction (56-64%; p<0.05) in the number of infectious elementary bodies following smoke exposure compared to untreated cultures. Under the same conditions, at late time points, smoke-exposed cultures showed significantly fewer chlamydial DNA copies (p<0.04). Moreover, smoke exposure induced large aberrant bodies that predominated within the inclusion. Following in vitro smoke exposure, alterations in the developmental cycle of C. pneumoniae included: inhibition of productive infection, reduced bacterial cell division, and formation of aberrant bodies. Thus, using this novel system, we were able to induce chlamydial persistence. Tobacco smoke exposure may represent a risk for establishment of a chronic reservoir of C. pneumoniae infection within respiratory epithelium.
authors.affiliation: Department of Pediatrics, School of Medicine, University of California Davis, 2516 Stockton Blvd, Sacramento, CA 95618, USA.
authors.forename: Jean A
authors.initials: JA
authors.lastname: Wiedeman
authors.forename: Ravi
authors.initials: R
authors.lastname: Kaul
authors.forename: Luke S
authors.initials: LS
authors.lastname: Heuer
authors.forename: Nao N
authors.initials: NN
authors.lastname: Thao
authors.forename: Kent E
authors.initials: KE
authors.lastname: Pinkerton
authors.forename: Wanda M
authors.initials: WM
authors.lastname: Wenman
mesh_terms: D045744:Cell Line, Tumor; D016993:Chlamydophila pneumoniae / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity*; D003470:Culture Media; D004847:Epithelial Cells / Q000382:microbiology / Q000473:pathology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007830:Larynx / Q000166:cytology / Q000382:microbiology* / Q000473:pathology; D008854:Microscopy, Electron; D016133:Polymerase Chain Reaction; D012906:Smoke
chemical_list: D003470:Culture Media; D012906:Smoke