Apoptosis in BEAS-2B bronchial epithelial cells following up-regulation of pirin levels by infection with AdPirin. BEAS-2B cells were infected with AdPirin, AdNull, or control (naive) and TdT-mediated dUTP nick end labeling (TUNEL) was used to assess apoptosis after 24 hr. A. control (naive); B. AdNull (104 particle units); and C. AdPirin (104 particle units). D. Quantitative assessment of apoptosis in BEAS-2B bronchial epithelial cells exposed to AdPirin, AdNull or control by TUNEL assay. The percentage of apoptotic cells per 10× field were manually counted in 10 fields per slide, with three replicates.