title: Infection of Human Retinal Pigment Epithelium with Chlamydia trachomatis.
abstract: OBJECTIVE
  Little is known about the susceptibility of posterior segment tissues, particularly the human retinal pigment epithelium (hRPE), to Chlamydia trachomatis. The purpose of the study was to investigate the possibility of infecting the hRPE with Chlamydia trachomatis, and to examine the infectivity of different Chlamydia trachomatis clinical isolates for hRPE cells and the hRPE cell response to the infection.
  
  
  METHODS
  Cultured hRPE and McCoy cells were inoculated with eight Chlamydia trachomatis (serovar E) clinical isolates at multiplicity of infection (MOI) of 2.0 or 0.3. To detect Chlamydia trachomatis, samples were stained immunohistochemically with anti-major outer membrane protein antibodies at 24h, 48h, and 72h postinoculation (PI). The changes in the expression of signaling molecules and proteins of cytoskeleton and extracellular matrix in hRPE cells were examined immunohistochemically.
  
  
  RESULTS
  All eight clinical isolates demonstrated ability to infect hRPE cells. At equal MOI of 0.3, the infectivity of Chlamydia trachomatis clinical isolates for RPE culture was found to be at least as high as that for McCoy cell culture. At 24h PI, the percentage of inclusion-containing cells varied from 1.5 ± 0.52 to 14.6 ± 3.3% in hRPE cell culture infected at MOI of 2.0 against 0.37 ± 0.34 to 8.9 ± 0.2% in McCoy cell culture infected at MOI of 0.3. Collagen type I, collagen type IV, basic fibroblast growth factor, transforming growth factor-beta and interleukin-8 expression at 48h PI were maximally increased, by 2.1-, 1.3-, 1.5-, 1.5- and 1.6-fold, respectively, in the Chlamydia trachomatis-infected compared with control hRPE cell culture specimens (P < 0.05).
  
  
  CONCLUSIONS
  This study, for the first time, proved the possibility of infecting hRPE cultured cells with Chlamydia trachomatis, which leads to proproliferative and proinflammatory changes in the expression of signaling molecules and extracellular matrix components.
authors.affiliation: Department of Ophthalmology, Military Medical Academy, St Petersburg, Russia.|St. Petersburg Branch of the Academician S. Fyodorov IRTC "Eye Microsurgery", St. Petersburg, Russia.
authors.forename: Ernest
authors.initials: E
authors.lastname: Boiko
authors.affiliation: Department of Ophthalmology, Military Medical Academy, St Petersburg, Russia.
authors.forename: Dmitrii
authors.initials: D
authors.lastname: Maltsev
authors.affiliation: Laboratory of Microbiology, D.O. Ott Research Institute of Obstetrics and Gynaecology, St. Petersburg, Russia.
authors.forename: Alevtina
authors.initials: A
authors.lastname: Savicheva
authors.affiliation: Laboratory of Microbiology, D.O. Ott Research Institute of Obstetrics and Gynaecology, St. Petersburg, Russia.
authors.forename: Kira
authors.initials: K
authors.lastname: Shalepo
authors.affiliation: Laboratory of Microbiology, D.O. Ott Research Institute of Obstetrics and Gynaecology, St. Petersburg, Russia.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Khusnutdinova
authors.affiliation: Department of Ophthalmology, Military Medical Academy, St Petersburg, Russia.
authors.forename: Alexei
authors.initials: A
authors.lastname: Pozniak
authors.affiliation: Pathology Department, D.O. Ott Research Institute of Obstetrics and Gynaecology, St. Petersburg, Russia.
authors.forename: Igor
authors.initials: I
authors.lastname: Kvetnoi
authors.affiliation: Pathology Department, D.O. Ott Research Institute of Obstetrics and Gynaecology, St. Petersburg, Russia.
authors.forename: Viktoria
authors.initials: V
authors.lastname: Polyakova
authors.affiliation: Department of Ophthalmology, Military Medical Academy, St Petersburg, Russia.
authors.forename: Alexei
authors.initials: A
authors.lastname: Suetov
mesh_terms: D015415:Biomarkers / Q000378:metabolism*; D002478:Cells, Cultured; D002690:Chlamydia Infections / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D002692:Chlamydia trachomatis / Q000472:pathogenicity*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*
chemical_list: D015415:Biomarkers