CCR5 and infection: While 2-LTR circles and the number of integrated proviral DNA were only above the detection limit (10 copies) at 72 h post-infection, a result of slower infection kinetics and relatively lower level of infection in MDDCs compared with HuT/CCR5-cells, the level of 2-LTR and integrated viral species were higher in the presence of Vpr (Fig. 4E and 4F).