Given that influenza NP contains a conserved immunodominant CD8 T-cell epitope shared among all influenza A virus and that mucosal immunization can stimulate both mucosal and systemic immune responses, we believe that i.n. immunization with rAd/NP can induce protective immunity against different strains of influenza virus by priming for cross-reactive NP-specific CTL response and possibly by local and systemic induction of NP-specific antibodies. This evidence concerns the gene CD8A and influenza.