Replication kinetics in MDCK cells and chicken embryos
Growth properties of rescued mutant and parental viruses were compared in MDCK cells and chicken embryos. Each virus was inoculated onto MDCK monolayers and nine-day old chicken embryos at a multiplicity of infection (MOI) of 0.001 and 103EID50, respectively. The supernatants of the infected cells and chicken embryos were collected in triplicate at 2, 4, 6, 12, 24, 36, 48 and 72 h post inoculation and stored at -80oC. The titer of each sample was determined using Quantitative real time PCR (qRT-PCR) and HA tests.