The glycoprotein of vesicular stomatitis virus promotes release of virus-like particles from tetherin-positive cells
(A) 293T cells were transiently transfected with rising amounts of plasmid encoding human tetherin. At 24 h post transfection cells were infected with VSV at an MOI of 0.001 washed and viral titers present in culture supernatants were determined at 8 h post infection. Titers measured in the absence of tetherin were set to 100%. The average of six independent experiments is shown, error bars indicate standard error of the mean (SEM). Unpaired two-tailed Student’s t-test was used to examine whether differences in titers obtained from cells transiently expressing tetherin versus cells transfected with empty expression vector are of statistical significance (*, p ≤ 0.05; **, p ≤ 0.005; ***, p ≤ 0.001). (B) HeLa cells were transfected with the indicated siRNAs. At 48 h post transfection, cells were harvested and stained with anti-tetherin antibody. Cell staining was then analyzed by flow cytometry. The results of a single representative experiment carried out with triplicate samples are shown, in which tetherin surface expression levels in cells transfected with control siRNA (scrambled) were set as 100%. Error bars indicate standard deviation (SD). An unpaired two-tailed Student’s t-test was used to assess statistical significance (***, p ≤ 0.001). (C) HeLa cells were transfected with the indicated siRNAs and at 24 h post transfection cells were infected with VSV at an MOI of 0.005 At 12 h post infection, viral titers in culture supernatants were determined. The results of a single representative experiment conducted with triplicate samples are shown and were confirmed in two separate experiments. Error bars indicate standard deviation. To test whether differences in VSV titers measured for cells transfected with control (scrambled) and tetherin-specific siRNA were statistically significant, an unpaired two-tailed Student’s t-test was performed (**, p ≤ 0.05).