Replication kinetics (multistep growth curve) of different reassortant avian influenza viruses (clones C5, C8, C11, C20, and C46) and the HPAIV H5N1 parent strain (A/chicken/Egypt/AR236/2015) in MDCK cells. Subconfluent monolayers of MDCK cells were infected with each of the reassortant clones (C5, C8, C11, C20, and C46) or the parental virus (HPAIV H5N1 A/chicken/Egypt/AR236/2015) at a multiplicity of infection of 0.001. Virus titers in the supernatants were measured in triplicate at 1, 8, 24, 48, and 72 h. Statistically significant differences from the titers of the parental virus (AR236) were observed for C5, C8, and C11 at 8 h after infection and for C46 at 24 h and at 48 h after infection (P < 0.01).