Influenza vaccines can be produced not only in embryonated chicken eggs but also through cell culture processes. This thesis aimed to optimize these processes by characterizing influenza virus infection dynamics and virus-induced apoptosis in host cells. Flow cytometric staining of the influenza virus NP protein tracked infection over time, while a TUNEL assay assessed apoptosis progression. The study involved infecting adherent Madin-Darby canine kidney (MDCK) cells with various influenza virus strains at different multiplicities of infection (MOI) and examining defective interfering particles (DIPs). Additionally, infections were conducted in stirred tank bioreactors, and the MDCK. SUS2 suspension cell line was evaluated for virus propagation. The findings indicated that low MOI conditions enhance infectious virus yields in influenza A virus production, with infection dynamics varying by virus strain, particularly regarding apoptosis. The presence of DIPs in the seed virus significantly affected infectious virus yields. Furthermore, the MDCK suspension cell line emerged as a viable alternative to adherent MDCK cells, facilitating a more scalable production process. This work enhances the understanding of influenza virus propagation in cell culture and offers insights for optimizing upstream processing in vaccine production.
