Figure 6.

Apoptosis of CD8⁺ lymphocytes in peripheral tissues. Lymphocytes isolated from liver, BAL, spleen, and mediastinal lymph nodes were analyzed by flow cytometry for CD8 expression and DNA fragmentation (TUNEL assay) 10 days after infection of naïve mice with HKx31 influenza virus. TUNEL staining (+ TdT, Left) and negative control staining (− TdT, Right) are shown for each tissue. The percentages represent the proportion of cells analyzed in a lymphocyte gate found in each quadrant respectively (forward-light scatter vs. side-scatter characteristics).