Figure 5.

Vpu-induced apoptosis involves activation of the caspase pathway. CD4U and CD4U_2/6 cell lines were cultured in complete DMEM medium in the presence or absence of Dox for 24 h. TNF-α (20 ng/ml) and z-VAD-fmk (50 μM) were then added where indicated and the cultures were incubated for an additional 16 h before analysis. (A) Cultures were evaluated for induction of apoptosis by annexin V staining. Error bars reflect SDs from three independent experiments. (B) The same cultures were analyzed by flow cytometry for the expression of the active form of caspase-3 using a FITC-conjugated rabbit antiactive caspase-3 polyclonal antibody. The numbers indicate percentages of FITC-positive cells.