FIG. 5.

Effect of p27^Kip1 deficiency on apoptosis of effector CD8 T cells. (A) At days 8 and 11 p.i, splenocytes from +/+ and −/− mice were stained with anti-CD8, MHC-I tetramers, and annexin V to quantitate proapoptotic cells directly ex vivo. The percentage of annexin V^high tetramer-binding CD8 T cells was analyzed by flow cytometry. (B) At days 8 and 11 p.i, splenocytes were cultured for 4 h in vitro. After culture, the cells were stained with MHC-I tetramers, anti-CD8, and anti-caspase-3. Histograms are gated on D^b/NP396 or D^b/GP33 tetramer-binding CD8 T cells.