Few viruses have had such large effect on humanity as influenza. Apart from regular seasonal outbreaks of respiratory disease in humans, these viruses have caused pandemics with high mortality rates. Pandemics are the result of interspecies transmission events, followed by adaptations to new hosts. When viruses, or virus variants, with novel antigenic properties are introduced into a susceptible population lacking herd immunity, pandemics may start. The aim of this project is to gain more knowledge about the role of the host immune response against different influenza A viruses (IAVs) for 1- better understanding of the molecular mechanisms responsible for interspecies transmission; 2-revealing molecular targets against IAV, and 3-understanding virus ecology using RNAseq, single cell transcriptomics and spatial transcriptomics.