Figure 3

Disruption of CD4 dimerization is associated with increased HIV-1 entry into target cells. A201 CD4-WT, A201 CD4-E91K, E92K and A201 CD4-Q344E cell populations were incubated 3 hours with increasing viral inputs, as determined by standard reverse transcriptase (RT) assays, of NL4, 3-luc-1558 (A, B and C) and NL4, 3-luc-HXB (D) virions containing BlaM-Vpr fusion protein. (A and D) Following a 3 hours adsoption period, a portion of cells were treated with CCF2-AM and analyzed by flow cytometry, 16 hours later. Each assay was done in duplicate and results are representative of 3 and 2 experiments, respectively. (B and C) The remaining infected cells were washed and incubated in fresh medium for 40 hours before lysis. Luciferase activity was determined in equivalent amount of lysates. Each luciferase activity assay was done in duplicate and results are representative of 2 to 4 independent experiments. Mean CD4 expression for each cell line was determined before each assay and is indicated in parenthesis. R.L.U., relative luciferase units.