Figure 1

Lower efficiency of human CCR5 use by CD4-independent compared to CD4-dependent SIV Envs. Pseudotyped viruses carrying Envs from d42 CD4+ T cell depleted macaques (CD4-independent Envs; open circles) or control macaques (CD4-dependent Envs; closed circles) were used infect 293 T cells transfected with receptor molecules (A,B) or primary human PBMCs (C). (A) 293 T cells were transfected with rhesus macaque (RM) CCR5 with or without rhesus CD4 and infected with pseudotype viruses. Entry was assessed based on luciferase production 72 hours after infection and expressed as relative light units (RLU). (B) SIV Env-pseudotyped viruses were used to infect 293 T cells transfected with human CCR5 with or without human CD4. (C) Envs were assessed for their ability to mediate viral entry into PHA/IL2-stimulated human PMBCs that were pre-treated with or without a CD4 blocking antibody (mAb #19). Unpaired T-tests were used to compare entry between the 2 sets of Envs in a given target cell type, while paired T-tests were used to compare entry of Envs in the presence versus absence of CD4.