A Herpes Simplex Virus Type-1-derived influenza vaccine induces balanced adaptive immune responses and protects mice from lethal influenza virus challenge.
Influenza virus is a major respiratory viral pathogen responsible for the deaths of hundreds of thousands worldwide each year. Current vaccines provide protection primarily by inducing strain-specific antibody responses with the requirement of a match between vaccine strains and circulating strains. It has been suggested that anti-influenza T-cell responses, in addition to antibody responses may provide the broadest protection against different flu strains. Therefore, to address this urgent need, it is desirable to develop a vaccine candidate with an ability to induce balanced adaptive immunity including cell mediated immune responses. A live viral vector technology should exhibit safety, immunogenicity, effectiveness in the presence of pre-existing immunity, and the ability to induce mucosal immune responses. Here, we used VC2, an established Herpes Simplex Virus type 1 vaccine vector, to express the influenza HA protein. We show that this virus is capable of generating potent and specific anti-influenza humoral and cell-mediated immune responses. We further show that a single vaccination with the VC2-derived influenza vaccine protects mice from lethal challenge with influenza virus. Our data support the continued development of VC2-derived influenza vaccines for protection of human populations from both seasonal and pandemic strains of influenza. Finally, our results support the potential of VC2-derived vaccines as a platform for the rapid development of vaccines against emerging and established pathogens, particularly respiratory pathogens.