RT Journal Article SR Electronic(1) A1 Kochs, Georg A1 Martínez-Sobrido, Luis A1 Lienenklaus, Stefan A1 Weiss, Siegfried A1 García-Sastre, Adolfo A1 Staeheli, PeterYR 2009 T1 Strong interferon-inducing capacity of a highly virulent variant of influenza A virus strain PR8 with deletions in the NS1 gene JF Journal of General Virology, VO 90 IS 12 SP 2990 OP 2994 DO https://doi.org/10.1099/vir.0.015727-0 PB Microbiology Society, SN 1465-2099, AB Influenza viruses lacking the interferon (IFN)-antagonistic non-structural NS1 protein are strongly attenuated. Here, we show that mutants of a highly virulent variant of A/PR/8/34 (H1N1) carrying either a complete deletion or C-terminal truncations of NS1 were far more potent inducers of IFN in infected mice than NS1 mutants derived from standard A/PR/8/34. Efficient induction of IFN correlated with successful initial virus replication in mouse lungs, indicating that the IFN response is boosted by enhanced viral activity. As the new NS1 mutants can be handled in standard biosafety laboratories, they represent convenient novel tools for studying virus-induced IFN expression in vivo., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.015727-0