IFNL1 and infection: To assess the antiviral potential and kinetic differences of type I and type III IFN responses in bat organoids, we infected bat nasalORG or SIORG with VSV-eGFP, a fast-replicating virus sensitive to bat IFN4, and treated them with recombinant universal IFNα2, bat IFNλ1-like or bat IFNλ3-like, 12 h before infection (before treatment), during infection (co-treatment) or 8 h after infection (after treatment) (Fig. 8a).