Oral keratinocytes support non-replicative infection and transfer of harbored HIV-1 to permissive cells.
BACKGROUND
Oral keratinocytes on the mucosal surface are frequently exposed to HIV-1 through contact with infected sexual partners or nursing mothers. To determine the plausibility that oral keratinocytes are primary targets of HIV-1, we tested the hypothesis that HIV-1 infects oral keratinocytes in a restricted manner.


RESULTS
To study the fate of HIV-1, immortalized oral keratinocytes (OKF6/TERT-2; TERT-2 cells) were characterized for the fate of HIV-specific RNA and DNA. At 6 h post inoculation with X4 or R5-tropic HIV-1, HIV-1gag RNA was detected maximally within TERT-2 cells. Reverse transcriptase activity in TERT-2 cells was confirmed by VSV-G-mediated infection with HIV-NL4-3Deltaenv-EGFP. AZT inhibited EGFP expression in a dose-dependent manner, suggesting that viral replication can be supported if receptors are bypassed. Within 3 h post inoculation, integrated HIV-1 DNA was detected in TERT-2 cell nuclei and persisted after subculture. Multiply spliced and unspliced HIV-1 mRNAs were not detectable up to 72 h post inoculation, suggesting that HIV replication may abort and that infection is non-productive. Within 48 h post inoculation, however, virus harbored by CD4 negative TERT-2 cells trans infected co-cultured peripheral blood mononuclear cells (PBMCs) or MOLT4 cells (CD4+ CCR5+) by direct cell-to-cell transfer or by releasing low levels of infectious virions. Primary tonsil epithelial cells also trans infected HIV-1 to permissive cells in a donor-specific manner.


CONCLUSIONS
Oral keratinocytes appear, therefore, to support stable non-replicative integration, while harboring and transmitting infectious X4- or R5-tropic HIV-1 to permissive cells for up to 48 h.
Vacharaksa
Anjalee
A
Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA. tang0160@umn.edu
Asrani
Anil C
AC
Gebhard
Kristin H
KH
Fasching
Claudine E
CE
Giacaman
Rodrigo A
RA
Janoff
Edward N
EN
Ross
Karen F
KF
Herzberg
Mark C
MC
D002461:Cell Line, Transformed; D002478:Cells, Cultured; D018920:Coculture Techniques; D004847:Epithelial Cells / Q000166:cytology / Q000821:virology; D015497:HIV-1 / Q000472:pathogenicity / Q000502:physiology; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000821:virology*; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000821:virology; D009061:Mouth Mucosa / Q000166:cytology / Q000821:virology*; D014066:Palatine Tonsil / Q000166:cytology / Q000821:virology; D019098:Telomerase; D016662:Virus Integration; D014779:Virus Replication
C509186:TERT protein, human; D019098:Telomerase