FIG. 2.

Virion-associated Vpr causes activation of caspases 3, 8, and 9. Jurkat cells were mock infected or infected with Vpr(+)^trans or Vpr(−) viruses at an MOI of 0.5. (A) Fifty hours postinfection, the percentage of infected cells was determined by flow cytometry through EGFP expression. (B) Fifty hours postinfection, caspase 3/7, 8, and 9 activities were measured using the appropriate Caspase-Glo assay. Uninfected cells treated with 12.5 ng/ml of the Fas CH11 antibody for 4 to 6 h were used as a positive control for the assay. Blank values were subtracted, and the increase in activity was calculated based on activity measured from mock-infected cells. The black, white, and gray bars represent caspase 3/7, 8, and 9 activities, respectively. Data shown are representative of one of four independent experiments performed in triplicate. The results are shown as means ± standard deviations. Infection with NLEGFP viruses was used as a reference.