Intranasal mixed regimen with dNS1-based virus and STFKB vaccine could induce both system and mucosal humoral immunity

This study demonstrates that an intranasal mixed vaccination regimen combining a dNS1-based live-attenuated virus and an STFKB subunit vaccine effectively induces robust humoral immunity at both systemic and mucosal sites. Compared to single-component regimens, the mixed approach elicited significantly higher levels of antigen-specific serum IgG antibodies, indicative of systemic immunity. Crucially, it also generated potent mucosal IgA responses in respiratory tissues (e.g., nasal washes, lung lavages) and distal mucosal sites. These findings highlight the potential of this combinatorial intranasal strategy to provide dual-layered immune protection against respiratory pathogens by simultaneously engaging systemic and local mucosal defenses. Overall design: Mice were intranasally immunized in four groups: (1) dNS1-based live-attenuated virus alone, (2) STFKB subunit vaccine alone, (3) a mixture of dNS1-virus and STFKB vaccine, and (4) a negative control (vehicle). At defined post-immunization timepoints, Single-cell suspensions were prepared from lung tissues and subjected to single-cell RNA sequencing (scRNA-seq) to comprehensively profile the global transcriptional landscape of immune cells.