title: Porphyromonas gingivalis induces CCR5-dependent transfer of infectious HIV-1 from oral keratinocytes to permissive cells.
abstract: BACKGROUND
  Systemic infection with HIV occurs infrequently through the oral route. The frequency of occurrence may be increased by concomitant bacterial infection of the oral tissues, since co-infection and inflammation of some cell types increases HIV-1 replication. A putative periodontal pathogen, Porphyromonas gingivalis selectively up-regulates expression of the HIV-1 coreceptor CCR5 on oral keratinocytes. We, therefore, hypothesized that P. gingivalis modulates the outcome of HIV infection in oral epithelial cells.
  
  
  RESULTS
  Oral and tonsil epithelial cells were pre-incubated with P. gingivalis, and inoculated with either an X4- or R5-type HIV-1. Between 6 and 48 hours post-inoculation, P. gingivalis selectively increased the infectivity of R5-tropic HIV-1 from oral and tonsil keratinocytes; infectivity of X4-tropic HIV-1 remained unchanged. Oral keratinocytes appeared to harbor infectious HIV-1, with no evidence of productive infection. HIV-1 was harbored at highest levels during the first 6 hours after HIV exposure and decreased to barely detectable levels at 48 hours. HIV did not appear to co-localize with P. gingivalis, which increased selective R5-tropic HIV-1 trans infection from keratinocytes to permissive cells. When CCR5 was selectively blocked, HIV-1 trans infection was reduced.
  
  
  CONCLUSIONS
  P. gingivalis up-regulation of CCR5 increases trans infection of harbored R5-tropic HIV-1 from oral keratinocytes to permissive cells. Oral infections such as periodontitis may, therefore, increase risk for oral infection and dissemination of R5-tropic HIV-1.
authors: Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA. giac0015@umn.edu
authors: Rodrigo A
authors: RA
authors: Giacaman
authors: Anil C
authors: AC
authors: Asrani
authors: Kristin H
authors: KH
authors: Gebhard
authors: Elizabeth A
authors: EA
authors: Dietrich
authors: Anjalee
authors: A
authors: Vacharaksa
authors: Karen F
authors: KF
authors: Ross
authors: Mark C
authors: MC
authors: Herzberg
mesh_terms: D016866:Bacteroidaceae Infections / Q000382:microbiology; D002460:Cell Line; D018920:Coculture Techniques; D004847:Epithelial Cells / Q000276:immunology / Q000821:virology; D015658:HIV Infections / Q000821:virology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D015603:Keratinocytes / Q000382:microbiology*; D009061:Mouth Mucosa / Q000166:cytology / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000502:physiology*; D019713:Receptors, CCR5 / Q000378:metabolism*; D012307:Risk Factors; D014779:Virus Replication
chemical_list: D019713:Receptors, CCR5