Figure 2. Effects of HIV-1 gp120 on the cell viability of HRCEC. A: Dose–response effects of HIV-1 gp120 for 24 h in an MTT assay. B: Time course of the effects of HIV-1 gp120 on HRCEC. HRCEC were incubated with 0.08 mg/l of HIV-1 gp120 for the times indicated. Cellular viability=(absorbance rate of study group÷absorbance rate of control group) ×100%.*p<0.05, # p<0.01 compared with control (HIV-1 gp120 mutated proteins, 423 I/P). Each data point represents the mean±SD of three independent experiments.