Groups of BALB/c mice were immunized with either IDLV-NP, or IDLVGFP as a specificity control to rule out innate immune protection due to the vector. Mice that received PBS served as negative control for protection. In this study, we assessed the feasibility of administering IDLV by the i.n. route to induce an antigen-specific immune response and protect against influenza virus. IDLV is an attractive platform for vaccine delivery since they, like ICLV, have the potential to robustly activate both the cell-mediated and humoral arms of the immune system, but they have the safety advantage of doing so without integrating into the cell genome. We constructed IDLV expressing influenza NP, which is the major target for host T cell responses, because these NPspecific responses have been shown to be protective against homologous and heterosubtypic influenza virus challenge in mice. Antibodies against NP may also help to promote resistance to influenza virus infection. Our results clearly indicate that immunization with Homatropine Bromide IDLV-NP strongly induces both cell-mediated and humoral NP-specific immune responses in mice. Furthermore, a repeated dose of IDLV-NP enhance NP-specific immune responses, suggesting either that IDLV-NP did not elicit anti-vector immunity, or that anti-vector immunity did not interfere with the ability of the mice to mount antigen-specific immune responses following vector readministration in this system. This result is consistent with the known lack of pre-existing immunity and negligible host immune response against LV. This is also the first study to demonstrate that IDLV, when administered via the i.n. route, can protect against a viral infection. In our study, the ability of IDLV-NP to confer protective immunity against homologous or heterosubtypic influenza virus challenge was strongly Isosorbide dependent on the route of administration. In fact, full protection was only achieved with 2 doses of IDLV-NP administered by the i.n. route, but not by the i.m. route.Our finding is in agreement with other reports of viral vector-based vaccines expressing NP, or other conserved influenza proteins, that have shown to be more effective when administered by the i.n. route, compared to other routes.