FIGURE 4.

Influenza H1N1-mediated TGFβ activity induces cell death in human bronchial epithelial cells. iHBECs were assessed for apoptotic or necrotic cell death by staining with annexin V (FITC) and propidium iodide (PE) and analyzed via flow cytometry. Cells in Q1 were FITC⁻/PE⁺ signifying necrosis. In Q2 cells were FITC⁺/PE⁺ and represent those in late apoptosis. Cells in early apoptosis were in Q3 and stained FITC⁺/PE⁻ whereas those in Q4 were FITC⁻/PE⁻ and represented a healthy population. Cells infected with influenza at m.o.i. 2 are shown in A compared with untreated cells in media alone (B), mock infection with media containing TPCK-trypsin (C), and cells stimulated with 500 pg/ml TGFβ (D). Cells infected with influenza at m.o.i. 2 in the presence of the αvβ6-blocking antibody 6.3G9 are shown in E and mock infection with TPCK-trypsin in the presence of the αvβ6-blocking antibody 6.3G9 (F). The percentages of cells in each quadrant are recorded in the respective quadrants. G, graphical representation of the proportion of cells in each quadrant under each condition. White, healthy; light gray, early apoptosis; dark gray, late apoptosis, and black, necrotic.