FIG 6.

The absence of nef and/or vpu, or treatment with MLN4924, sensitizes infected cells to ADCC, but the effect of MLN is not specific to cells expressing Vpu. (A and B) CEM.NKR.luc cells, which contain a luciferase indicator gene under the control of an HIV LTR, were either uninfected or infected for 4 days with the indicated viruses and then mixed with cells of an NK line at a 10:1 effector/target (E/T) ratio in the presence of increasing concentrations of HIV IgG and incubated for 8 h. The amount of viable cells was determined by luminescence and normalized to the signal of a no-IgG sample for each indicated condition, which was set to 1. Fractional cell survival (y axis) is graphed versus the concentration of HIV-IgG (x axis) on a log-log plot. Trend lines were determined using Excel. (A) Sensitivities of the various viruses; (B) effects of 200 nM MLN4924 (used as described below) on the sensitivity of uninfected cells and cells infected with either wild-type virus or virus lacking vpu and nef. (C) CEM.NKR.luc cells, either uninfected or infected for 4 days with the indicated viruses, were preincubated with 200 nM MLN4924 in DMSO or with DMSO alone for 4 h and then mixed with cells of an NK line at a 10:1 E/T ratio in the presence of 0.75 μg/ml HIV IgG or 2.5 μg/ml A32 and incubated for 8 h either with 200 nM MLN in DMSO or with DMSO alone, in triplicate. The amount of viable cells was determined by luminescence and normalized to the signal of a no-IgG sample for each indicated condition, which was set to 1 as described for panels A and B. Error bars indicate ±standard deviations of triplicates.