Exogenous deoxynucleosides and SAMHD1 KD do not rescue SIV from the antiviral state. MDDCs were treated for 3 hrs with 3 mM deoxynucleosides (dN) and either challenged with a VSV G pseudotyped SIV-GFP reporter vector deleted for Vpx (SIVΔVpx) or not (SIV Vpx+) or with an HIV-1-GFP reporter vector. The viruses were normalized by titration on HeLa cells. Values are displayed in %GFP positive cells (A) or fold rescue by exogenous deoxynucleosides (B). MDDCs were stimulated with 100 ng/ml LPS for 18 hrs, treated with 2.5 mM deoxynucleosides (dN) for 2 hrs and challenged with a SIVΔVpx or HIV-1 reporter vector. Values are displayed in %GFP positive cells (C) or fold-rescue by exogenous deoxynucleosides (D). To achieve SAMHD1 knockdown, freshly isolated CD14+ monocytes were treated for 2 hrs with Vpx-VLPs and then transduced with a lentiviral vector expressing shRNA targeting SAMHD1 (SAMHD1 KD) or luciferase (control KD) and differentiated into MDDCs over 5 days. 0.5 × 106 were used to assess knockdown efficency by western blot (E). Knockdown cells were stimulated with 100 ng/ml LPS and challenged with a Vpx + SIV GFP reporter vector (SIVMAC239) (F).