DP thymocytes lacking p110γ and p110δ are prone to apoptosis. (A) Representative flow cytometry profiles of annexin V staining of the PI^- population of DP thymocytes live-gated from WT control and p110γδ^-/- mice (n = 3). PI staining of the live-gated population of thymocytes was performed first to identify and thus exclude necrotic cells as defined by forward- and side-scatter parameters. Gates in the CD4⁺ and CD8⁺ panels indicate the DP thymocyte population gated for analysis of annexin V staining (histogram, which was exclusive of the PI⁺ staining, as stated). (B) Density plots of DP thymocytes harvested from WT control and p110γδ^-/- mice after treatment with BrdU. Representative histograms depict the percentages of DP cells that stained with BrdU (n = 3 for each group).