Fig. 1

Differential H5N1 virus replication in A549 or 293 T cells. a Immunofluorescence staining of A549 and 293 T cells at 36 h post-infection with A/QH at a MOI of 0.01. The influenza virus NP protein was analyzed with FITC-conjugated antibody.(top). The Nuclei was examined using DAPI staining (bottom). b Growth curve of influenza A viruses in A549 and 293 T cells. The cells were infected with A/QH virus (MOI of 0.01). Culture supernatants were collected at the indicated times and viral titers were determined by plaque forming units. c The cells were collected at 18 h after infection. The Western blot analysis was used to determine NP protein levels. β-actin is used as a control