Replication-incompetent HIV-NL4-3Δenv virus-like particles infect TERT-2 keratinocytes. Replication-incompetent HIV-NL4-3Δenv virus-like particles (VLPs) were packaged in 293T cells to express VSV-G protein as described in Materials and Methods. The TCID50 of VLPs was determined by titration in TZM-bl cells, and TERT-2 monolayers were then incubated for 6 h with VLPs at a MOI 10 (TCID50 per cell). Cells were then washed, trypsinized to remove unincorporated VLPs, and incubated for up to 48 h. Post inoculation, cells were fixed in 2% paraformaldehyde and nuclei were stained with DAPI (blue). (A) TERT-2 cultures were pre-incubated with AZT (0 to 2500 μM) before inoculation with VLPs. The expression of EGFP reporter gene was analyzed at 48 h post inoculation. (B) Kinetics of EGFP expression from 18 h to 48 h post inoculation. TERT-2 cells incubated with envelope-deficient particles were included as a negative control (48 h post inoculation). Arrows indicate EGFP expressing TERT-2 cells (green). Scale bar represent 50 μm. Images are representative of three independent experiments.