Plaque Formation with Influenza Viruses in Dog Kidney Cells

Summary Infectious influenza and parainfluenza viruses were produced as plaque-forming units (p.f.u.) in dog kidney cells (MDCK) after several passages of egg-grown viruses in MDCK monolayers. Virus titres of 106 to 1011 p.f.u./ml were obtained for several A and B strains of influenza and parainfluenza viruses.