Figure 2

CD4-independence is associated with reduced ability to use low levels of rmCCR5. SIV Env-pseudotyped viruses were tested for their ability to infect 293 T cells transfected with different amounts of rmCD4 and rmCCR5. (A,B) 3D plots showing entry by representative CD4-dependent (A) and CD4-independent (B) Envs. The horizontal (X) axis indicates the amount of transfected CCR5 decreasing from left to right, the depth (Z) axis indicates the amount of transfected CD4 decreasing from back to front, and the vertical (Y) axis indicates the level entry with 100% set at entry in the presence of maximal rmCD4 and rmCCR5. (C) The panel of Envs were tested as in A and B, with the X axis indicating CD4-independent entry (no CD4, maximal rmCCR5) and Y axis indicating entry via low CCR5 (maximal rmCD4 but only 10% of maximal rmCCR5). Each Env is indicated as a single point on the plot. Linear regression analysis was used to assess the correlation between CD4-independent entry and low-CCR5 entry.