text: Kinetics of gene expression during CD8+ T cell differentiation. (A) Kinetics of Prf1, Gzmb, Tbx21 (T-bet), and Eomes mRNA expression in differentiating P14 CD8+ T cells analyzed by Northern blotting. RNA from day 7 Th1 cells was used as a control. Sizes of mRNA transcripts are indicated. (B) Quantification of relative mRNA amounts by phosphorimager analysis. (C) Kinetics of protein expression in differentiating P14 CD8+ T cells analyzed by immunoblotting. Sizes of protein bands are indicated. (D) Relative protein amounts quantified from the Western blots. (E) Intracellular staining for granzyme B, IFN-gamma, and TNF. Granzyme B staining was specific relative to an isotype control (not depicted). Cells were restimulated with PMA and ionomycin for 4 h. (F) FACS-based assay to measure cytolytic activity of P14 CD8+ T cells against EL4 targets loaded with 0 (-) or 1 (+) muM Gp33 peptide (effector-to-target ratio = 5:1). Percentage of Annexin V+ (apoptotic) target cells in the CD8-negative EL4 target population (dot plots) was determined (histograms). Cytolytic activity was blocked by incubation with 2 mM EGTA (not depicted), confirming involvement of the granule exocytosis (perforin-granzyme B) pathway. Data are representative of at least five (A-E) or three (F) independent experiments. 
  