FIG 1.
Viral replication kinetics in Calu-3 cells. Polarized Calu-3 cells grown on 12-well Transwell inserts (∼5 × 105 per well) were infected with an MOI of 0.01 EID50 of HPAI Tky/1403 (H7N8), Can/504 (H7N3), NL/219 (H7N7), LPAI Tky/1573 (H7N8), Gs/NE/11, Anhui/1 (H7N9), or human seasonal A/Pan/99 (H3N2) virus. The cell culture supernatants were collected apically at 2, 24, 48, and 72 h p.i., and the viral titers were determined in eggs. Mean viral titers ± SD from triplicate cultures are shown. Statistical analysis was performed using two-way analysis of variance (ANOVA) with GraphPad Prism. Asterisks indicate statistically significant differences between the results for Anhui/1, HPAI H7N8, and NL/219 viruses and the results for the other H7 viruses tested at 24 h and between the results for HPAI and LPAI H7N8 viruses and Gs/NE/11 virus at 48 h. ***, P < 0.001.