SAMHD1 and infection: These results are in agreement with the reduction of HIV-1 p24-Gag observed with DMS, SKI II, and FTY720 pretreatment but lack of reduction of intracellular p24 with ABC294640 pretreatment in labeling/coculture experiments (Fig. 3), further supporting the proposed mechanism of HIV-1 infection inhibition occurring via a relative increase in SAMHD1 activation targeting preintegration events in the HIV-1 life cycle and reducing susceptibility to infection.