Influenza A virus replication is inhibited in IFN-λ2 and IFN-λ3 transfected or stimulated cells

Interferons lambda (IFN-lambda) are the most recently defined members of the class III cytokine family. To investigate whether IFN-lambda 2 and IFN-lambda 3 displayed antiviral activity against influenza A virus (IAV), a number of cell lines induced with IFNs - as well as two established cell lines (A549-IFN-lambda 2 and A549-IFN-lambda 3) - were infected with IAV. Our results indicate that IFN-lambda 2 has statistically significant antiviral activity in A549-IFN-lambda 2 (P = 0.0028) although less so than IFN-lambda 3, which reduced viral titer to 10% (P < 0.0001). The reverse was observed for cells treated with IFNs, with IFN-lambda 2-treated A549 cells inhibiting IAV infection more efficiently than IFN-lambda 3-treated A549 cells. The antiviral effect on IFN-stimulated cells was most apparent on Vero cells (compared with MOCK and HeLa). Both IFNs significantly inhibited IAV replication and inhibition was observed in a dose-dependent manner, with an optimal IFN concentration of 20 ng/ml. IFN-lambda 2 was more potent than IFN-lambda 3 on Vero cells while IFN-lambda 3 appeared more efficient than IFN-lambda 2 on MDCK and HeLa cells. (C) 2010 Elsevier B.V. All rights reserved.