RESUMO
Current influenza vaccine is not effective in providing cross-protection against variants. We evaluated the immunogenicity and efficacy of multi-subtype neuraminidase (NA) and M2 ectodomain virus-like particle (m-cNA-M2e VLP) and chimeric M2e-H3 stalk protein vaccines (M2e-H3 stalk) in ferrets. Our results showed that ferrets with recombinant m-cNA-M2e VLP or M2e-H3 stalk vaccination induced multi-vaccine antigen specific IgG antibodies (M2e, H3 stalk, NA), NA inhibition, antibody-secreting cells, and IFN-γ secreting cell responses. Ferrets immunized with either m-cNA-M2e VLP or M2e-H3 stalk vaccine were protected from H1N1 and H3N2 influenza viruses by lowering viral titers in nasal washes, trachea, and lungs after challenge. Vaccinated ferret antisera conferred broad humoral immunity in naïve mice. Our findings provide evidence that immunity to M2e and HA-stalk or M2e plus multi-subtype NA proteins induces cross-protection in ferrets.
Assuntos
Anticorpos Antivirais , Proteção Cruzada , Furões , Vírus da Influenza A Subtipo H1N1 , Vírus da Influenza A Subtipo H3N2 , Vacinas contra Influenza , Neuraminidase , Infecções por Orthomyxoviridae , Vacinas de Partículas Semelhantes a Vírus , Animais , Vacinas contra Influenza/imunologia , Vacinas contra Influenza/administração & dosagem , Proteção Cruzada/imunologia , Anticorpos Antivirais/imunologia , Neuraminidase/imunologia , Neuraminidase/genética , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Camundongos , Proteínas da Matriz Viral/imunologia , Proteínas da Matriz Viral/genética , Feminino , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Proteínas Viroporinas , Proteínas ViraisRESUMO
The conventional inactivated split seasonal influenza vaccine offers low efficacy, particularly in the elderly and against antigenic variants. Here, to improve the efficacy of seasonal vaccination for the elderly population, we tested whether supplementing seasonal bivalent (H1N1 + H3N2) split (S) vaccine with M2 ectodomain repeat and multi-subtype consensus neuraminidase (NA) proteins (N1 NA + N2 NA + flu B NA) on a virus-like particle (NA-M2e) would induce enhanced cross-protection against different influenza viruses in aged mice. Immunization with split vaccine plus NA-M2e (S + NA-M2e) increased vaccine-specific IgG antibodies towards T-helper type 1 responses and hemagglutination inhibition titers. Aged mice with NA-M2e supplemented vaccination were protected against homologous and heterologous viruses at higher efficacies, as evidenced by preventing weight loss, lowering lung viral loads, inducing broadly cross-protective humoral immunity, and IFN-γ+ CD4 and CD8 T cell responses than those with seasonal vaccine. Overall, this study supports a new strategy of NA-M2e supplemented vaccination to enhance protection against homologous and antigenically different viruses in the elderly.
