Abstract
Respiratory virus infections continue to pose a substantial global health challenge, requiring effective prophylactic and therapeutic strategies. Type III interferon (IFN-λ) has shown promise as an antiviral agent that strongly inhibits viral replication while minimizing systemic inflammation. Intranasal administration of IFN-λ allows easy access to the respiratory mucosa, enhancing localized antiviral responses. However, clinical application of IFN-λ is hindered by rapid mucociliary clearance, limited mucosal adhesion, and susceptibility to proteolytic degradation. Here, we develop nanoliposomes that can deliver IFN-λ through an intranasal route (NLp@IFN-λ) and act as an effective antiviral. We demonstrate that the nanoliposomes enable efficient penetration of IFN-λ in a mucus-mimicking model while allowing controlled release of the protein in vitro. NLp@IFN-λ treatment could effectively up-regulate interferon-stimulated genes in A549 cells, without inducing cytotoxicity. Finally, in vivo delivery of NLp@IFN-λ through a nasal route demonstrates prolonged retention and reduces viral load in nasal tissues in an infection model with influenza virus. This study demonstrates the potential of NLp@IFN-λ as an effective nasal delivery platform for prophylaxis of respiratory virus infections.