IFITM3 and infection: To address this issue, replication competent VSV, HIV-1, EBOV, MeV and WNV viruses were used at low MOI to challenge dox-inducible cell lines stably expressing IFITM3 (according to the scheme presented in Fig 7A) and viral spread through dox-induced or uninduced cultures was measured at the indicated time points post infection (Fig 7B).