FIG 5.

(A) Degradation of SAMHD1 by Vpx in lymphocytes. Flow cytometry histograms showing intracellular staining of SAMHD1 in lymphocytes infected with an NL4-3*GFP (left) or NL4-3*GFP with Vpx (right). Three days after infection, cells were fixed, permeabilized, and stained using a primary-specific SAMHD1 antibody followed by an allophycocyanin (APC)-conjugated secondary antibody (gray-line histogram, uninfected cells; black-line histogram, infected cells). The secondary antibody alone was used as a control (shaded histogram). Representative histograms of one experiment are shown. The experiment was performed in three independent donors. (B) Decreased sensitivity of thymidine NRTI in CD4⁺ T lymphocytes infected with HIV-1. Dose response of NRTI (AZT, d4T, 3TC, ddC, ABC, TFV, and ddI), NNRTI (NVP and EFV), and integrase inhibitor raltegravir as a control. PHA-activated CD4⁺ T lymphocytes were infected with or without Vpx using a GFP-expressing NL4-3 virus, modified to incorporate HIV-2 Vpx (NL4-3*GFP). Inhibition of HIV infection was measured as the percentage of GFP⁺ cells relative to the no-drug condition. Means ± SD from at least three independent donors performed in duplicate are shown. *, P < 0.05; **, P < 0.005; ***, P < 0.0005.