Suppression of PKK expression results in cell death of OCI-Ly10 cells. (A) OCI-Ly10 cells were infected with lentiviruses expressing either L-shControl or L-shPKK-1. At the indicated times after infection, the GFP-positive fractions were analyzed by flow cytometry. The GFP-positive fractions were normalized to the samples harvested at 2 days after infection. Means and SDs from 3 separate experiments are depicted. (B) OCI-Ly10 cells were infected as described in panel A, and the cell death was analyzed at 2 and 4 days after infection, respectively, using the annexinV-PE apoptosis detection kit (BD Bioscience). Shown are average results from 2 separate experiments. (C) OCI-Ly10 cells were infected as described in panel A. Three days after infection, expression of the indicated proteins was analyzed on Western blots.