FIG 7.
SM111-induced Vpu mutations abrogate CD4 and tetherin downregulation functions. (A) Representative flow cytometry data showing cell surface expression of CD4 (top) or tetherin (bottom) in CEM T cells transfected with a plasmid encoding GFP and wild-type (WT) or mutant Vpu sequences. Numbers in each plot indicate MFIs of CD4 or tetherin staining. Data are representative of three independent experiments. (B and C) CEM-GXR cells were infected with VSV-G-pseudotyped HIV-1NL4.3 or Vpu/Env mutant viruses as indicated, and cell surface expression of CD4 (B) or tetherin (C) was measured after 48 h by flow cytometry. Data are normalized to CD4 or tetherin expression on uninfected cells (dashed lines). (D) Uninfected CEM-GXR cells were treated with SM111, and cell surface expression of CD4, tetherin, or CXCR4 was measured after 2 days. Data are normalized to CD4, tetherin, or CXCR4 expression on untreated cells (dashed lines). For panels B to D, the means ± SD of results from three independent experiments are shown. *, P < 0.05 (two-tailed Student's t test).