SAMHD1 and HIV-1 infection: Given that HEK 293T and HeLa cell lines are highly permissive to post-entry HIV-1 infection[33], and express lower SAMHD1 compared to primary DCs (Figure7C), we investigated whether over-expression of SAMHD1 in these cells could cause an HIV-1-specific restriction phenotype and whether SAMHD1 retained its dNTP hydrolysis enzymatic activity.