Figure 5

The effects of immune activation on SAMHD1 expression and SIV-Vpx mediated SAMHD1 degradation.

(a) PBMC cells were stimulated with PI (1 μM PMA plus 1 μg/mL Ionomycin) for 24 h. Then, SAMHD1 expression in CD4⁺ T cells was assessed. Representative dot-plot results for SAMHD1 expression are presented. Percentages indicate absolute SAMHD1⁺ cell numbers. (b) Statistical analysis of data obtained as described in a was performed using the Mann-Whitney test. (c) PBMCs were pre-stimulated with IFN-α, or were not stimulated, for 24 h. Cells were then treated for another 48 h with SIV-Vpx or SIV-Mock. Histograms of SAMHD1 expression in activated CD4⁺ T cells, resting CD4⁺ T cells, and monocytes are presented. (d) Statistical analysis of data was performed using the Wilcoxon matched pairs test, data from HIV-1 infected individuals (n = 15). (e) Purified CD4⁺ T cells and monocytes were separated from PBMCs, pre-stimulated with PI or IFN-α, then treated with SIV-Vpx or SIV-Mock; whole cell lysates were examined by western blot analysis. Relative protein blot signal intensity analysis was performed using Li-Cor Image Studio software, numbers represent relative value normalized to β-Actin.