FIG. 9.

The sensitivity of syncytium formation to sCD4 is the same in the presence or absence of NKI-L16. 1G5 cells were preincubated or not preincubated with NKI-L16 (1 μg/ml) for 30 min and then mixed with J1.1 cells in the presence of different concentrations of sCD4 (0.025 to 20 μg/ml) for 12 h. After lysis, the samples were measured for luciferase activity. The results are given as the percent inhibition by a given concentration of sCD4 with respect to the untreated samples and are representative of the mean of three different luciferase counts.