The quest for a nanoparticle-based vaccine inducing broad protection to influenza viruses.

Influenza virus infections are a significant public threat and the best approach to prevent them is through vaccination. Because of the perpetual changes of circulating influenza strains, the efficacy of influenza vaccines rarely exceeds 50%. To improve the protection efficacy, we have designed a novel vaccine formulation that shows a broad range of protection. The formulation is made of the matrix protein 2 (M2e) and the nucleoprotein (NP) antigens. The multimerization of NP into nanoparticles improved significantly the immune response to NP. The combination of the NP nanoparticles with the PapMV-M2e nanoparticles enhances significantly the immune response directed to NP revealing the adjuvant property of the PapMV platform. The vaccine formulation combining these two types of nanoparticles protects mice from infectious challenges by two different influenza strains (H1N1 and H3N2) and is a promising influenza A vaccine capable to elicit a broad protection.