FIG 1.

Neutralization of SHIV-SF162P3 swarms after extensive passage in the presence of NIH45-46, CD4-Ig, or eCD4-Ig. SHIV-SF162P3 was amplified for three passages on GHOST CCR5⁺ cells in the absence of inhibitor and then was passaged for 60 rounds of selection in the presence of NIH45-46, CD4-Ig, or eCD4-Ig or in the absence of any inhibitor, as indicated. Inhibitor concentrations were determined from the estimated IC₉₀ values for the swarm at a given passage, up to 100 μg/ml. Passages were conducted in 3 (no inhibitor control), 4 (CD4-Ig), or 5 (NIH45-46 and eCD4-Ig) independent wells. Neutralization of each selected swarm was measured for each inhibitor, as indicated at the top of each panel. Dashed lines indicate neutralization curves for individual wells, and solid lines indicate averages among wells selected with the same inhibitor. Note that swarms selected with NIH45-46 (top right, green) and CD4-Ig (bottom left, red) were fully resistant to the respective inhibitors, whereas virus selected with eCD4-Ig remained partially sensitive to this inhibitor (bottom right, blue) but was fully resistant to CD4-Ig (bottom right, red). Error bars represent standard errors of the means (SEM).