Fig. 3From: Development of high-growth influenza H7N9 prepandemic candidate vaccine viruses in suspension MDCK cellsPlaque-forming ability of H7N9 reassortant viruses in MDCK cells with or without trypsin. The indicated viruses were diluted to the value shown in parentheses and MDCK cells were inoculated with the diluted viruses. The negative control indicates MDCK cells treated with DPBSBack to article page