Cross-protective and non-invasively administered vaccines are attractive and highly desired for the control of influenza. Self-assembling nanotechnology provides an opportunity for the development of vaccines with superior performance. In this study， an intranasal nanovaccine is developed targeting the conserved ectodomain of influenza matrix protein 2(M2e). 3-sequential repeats of M2e (3M2e) is presented on the self-assembling recombinant human heavy chain ferritin (rHF) cage to form the 3M2e-rHF nanoparticle. Intranasal vaccination with 3M2e-rHF nanoparticles in the absence of an adjuvant induces robust immune responses， including high titers of sera M2e-specific IgG antibodies， T-cell immune responses... More
Cross-protective and non-invasively administered vaccines are attractive and highly desired for the control of influenza. Self-assembling nanotechnology provides an opportunity for the development of vaccines with superior performance. In this study， an intranasal nanovaccine is developed targeting the conserved ectodomain of influenza matrix protein 2(M2e). 3-sequential repeats of M2e (3M2e) is presented on the self-assembling recombinant human heavy chain ferritin (rHF) cage to form the 3M2e-rHF nanoparticle. Intranasal vaccination with 3M2e-rHF nanoparticles in the absence of an adjuvant induces robust immune responses， including high titers of sera M2e-specific IgG antibodies， T-cell immune responses， and mucosal secretory-IgA antibodies in mice. The 3M2e-rHF nanoparticles also confer complete protection against a lethal infection of homo-subtypic H1N1 and hetero-subtypic H9N2 virus. An analysis of the mechanism of protection underlying the intranasal immunization with the 3M2e-rHF nanoparticle indicates that M2e-specific mucosal secretory-IgA and T-cell immune responses may play critical roles in the prevention of infection. The results suggest that the 3M2e-rHF nanoparticle is a promising， needle-free， intranasally administered， cross-protective influenza vaccine. The use of self-assembling nanovaccines could be an ideal strategy for developing vaccines with characteristics such as high immunogenicity， cross-protection， and convenient administration， as well as being economical and suitable for large-scale production.
