Crossing frontiers : impact of interferon-lambda(IFN-λ)on virus transmission

The type III interferon (IFN) family includes 4 IFN-λ subtypes in human and 2 in the mouse. IFN-λ preferentially acts on epithelial cells and mostly limits infection of epitheliotropic viruses. In this work, we studied whether IFN-λ could limit mouse-to-mouse propagation of the feco-orally transmitted mouse norovirus strain CW3 and of the sexually transmitted herpes virus MuHV-4. IFN-λ could prevent transmission of CW3 from infected seeders to prophylactically treated sentinels, but failed to prevent the transmission from infected seeders. MuHV-4 exhibited some resistance to IFN-λ treatment in vitro and in vivo. IFN-λ decreased early infection of the upper respiratory tract but failed to limit virus propagation and sexual transmission potential. Unlike mouse and human type I IFNs, type III IFNs were reported to act in a cross-specific fashion. In the second part, we re-examined the cross-specificity and observed that mouse and human IFN-λ exhibit some extent of species specificity, although not comparable to that of type I IFNs. Moreover, we developed a specific and sensitive firefly luciferase-based reporter cell line to detect IFN-λ in biological fluids.