Zooming into the spread and entry of influenza A viruses by correlative light and electron microscopy

Abstract text (incl. figure legends and references)

Influenza A viruses (IAV) cause annual epidemics and occasional pandemics typically resulting from zoonotic transfers. While it has been well established that the IAV are highly pleomorphic forming filamentous virions typically found in human isolates and spherical particles after lab adaptation, the benefits of filamentous virions in spread and entry inside lungs are not fully understood. Here, we used reverse genetics to create spherical and filamentous reporter viruses with the same genetic background. We apply cryo-correlative light and electron tomography to elucidate IAV entry in endosomes and established a correlative light and scanning electron microscopy to study IAV spread in a quantitative manner using plaque assays. Our data show differences in the spread of spherical and filamentous virions in different cell lines.