HIV-1 induces membrane extensions and Cdc42 activation in DCs. (A) Quantification by confocal microscopy of the number of membrane extensions or nanotubes in DCs either nonstimulated (NS) or stimulated with X4 HIV-1, R5 HIV-1, HIV-1Δenv, gp120IIIb, H-200, and X4 HIV-1 plus secramine A. Data are mean ± SD of 3 independent counts (left panel). Representative confocal images of DCs (right panel). Bar represents 5 μm. (B) Transmission electron microscopy images of HIV-1–treated DCs. Quantitation of the normalized number of membrane extensions on DCs after HIV-1 treatment. Data are mean ± SD of 2 independent counts (left panel) and corresponding representative images (right panel). Arrows indicate membrane extensions. *HIV-1 viral particles. Bar represents 2 μm. (C) Pull-down assay for activated Cdc42 in DC. Cdc42 expression by Western blot band quantitation. Data are mean ± SD of 3 independent pull-down experiments. (D) Western blot analysis for Phospho-Src (Φ-Src)/Src (left panel), Phospho-Pak1 (Φ-Pak1)/Pak1 (middle panel), and Phospho-Wasp (Φ-Wasp)/Wasp (right panel) detection in DCs. One representative Western blot per condition is represented. *P < .05 (Student t test).