(a) Confocal imaging of uninfected, wt ADA-infected or ΔNef-ADA-infected macrophages (Mφ) stained for Nef (red) or p24 (blue) in the presence of WGA (green). Leftmost panel shows number of long (> 100 μm) tethers/50 uninfected or infected macrophages. Original magnification, ×40. (b-d) ADA-infected macrophages cultured with or without IgD+ B cells and stained for Nef (red) and p24 or Pax5 (blue) in the presence of WGA (green). Original magnification, ×5 (b and c, upper panels), ×63 (b and c, lower panels), ×10 (d). (e, f) Percentage of THP-1-Nef-eGFP macrophage-like cells (Mφ) forming tethers and percentage of IgD+ B cells acquiring Nef-eGFP from Nef-eGFP-THP-1 cells in the presence or absence of chemical inhibitors (azide, latrunculin B, colchicin, nocodazole, wortmannin, AD101 or ADMD3100) or DN inhibitors (to β-arrestin-2, dynamin Ia, Arf6, Vav2, Cdc42, Rac1 or Rho). Control value corresponds to no inhibitor or empty construct and was set at 100%. Panels a-d show 1 of 4 experiments yielding similar results, whereas panels e and f summarize 3 experiments (bars indicate mean s.d.; asterisk is p < 0.05 compared to control). Scale bar equals 10 μm.