Figure 1.
Inhibition of NK lysis by PD098059. (A) YT cells untreated or treated 1 h at 37°C with 10–200 μM of the MEK1 inhibitor PD098059 or an amount of DMSO used to dilute the highest concentration of PD098059 were tested in triplicate wells for lysis of 51Cr-labeled Raji tumor cells at the E/T ratios indicated. (B) Highly enriched human LGL, freshly isolated by Percoll gradient centrifugation of nonadherent PBMCs, were preincubated with PD098059 at the indicated concentrations for l h at 37°C before testing for lysis against 51Cr-labeled K562 tumor cells. The SEM for each mean percent cytotoxicity of Raji or K562 tumor cells was <5% of the mean, and was not included.