Bacterium-like particles supplemented with inactivated influenza antigen induce cross-protective influenza-specific antibody responses through intranasal administration

► Supplementation of IN administered vaccine with BLP increases serum IgG. ► Supplementation of IN administered vaccine with BLP induces sIgA. ► In BLP-adjuvanted vaccine provides protection against live virus infection. ► In BLP-adjuvanted vaccine reduces lung viral titers compared to IM vaccination.