Human airway cells prevent SARS-CoV-2 multibasic cleavage site cell culture adaptation

Virus propagation methods generally use transformed cell lines to grow viruses from clinical specimens, which may force rapidly adapt culture conditions, a process facilitated by high viral mutation rates. Upon in VeroE6 cells, SARS-CoV-2 mutate or delete the multibasic cleavage site (MBCS) spike protein. Previously, we showed that MBCS facilitates serine protease-mediated entry into human airway cells (Mykytyn et al., 2021). Here, report propagating on line Calu-3 – expresses proteases prevents adaptations and directly adjacent (S686G). Similar results were obtained using organoid-based system for propagation. Thus, in-depth knowledge biology of virus can be used establish prevent adaptation.