本發明係關於適合在哺乳類動物中增加疫苗產量的馴化流感病毒株。此流感病毒株包含至少一修飾流感蛋白,其造成哺乳類宿主細胞,如非洲綠猴腎細胞增加流感病毒的產量。本發明也係關於流感病毒株所產生的疫苗。本發明更進一步係關於分離的修飾流感蛋白以及用來編碼成修飾流感蛋白之分離的核酸分子。The present invention relates to adapted influenza virus strains suitable for increased vaccine production for mammals. The influenza virus strains contain at least one modified influenza protein that results in increased production of the influenza virus from a mammalian host cell, such as a vero cell. The present invention also related to the vaccines produced from the influenza virus strains. The present invention further relates to isolated modified influenza proteins and isolated nucleic acid molecules that encode for the modified influenza proteins.