In Vivo Evaluation of the Adjuvant-Free Influenza Nucleoprotein Vaccine

Abstract Background: The influenza virus's Nucleoprotein (NP) is a highly conserved protein used in vaccine design. Alum, besides its neurotoxicity, is a commonly used adjuvant. Objectives: We tested the NP's efficacy as an alum-free flu vaccine. Methods: The recombinant vector (NP-pET-28a) was expressed in a prokaryotic system. Then, the immunogenicity of NP, alone or with alum, was evaluated in Balb/C mice by measuring IgGs (total and subtypes), interferon-gamma (IFN-γ), and interleukin-4 (IL-4) production and animal surveillance. Results: NP+Alum has 71.4% animal surveillance, whereas NP had 57.1%. While NP+Alum produced considerable IgGs, IFN-, and IL-4, NP alone showed promising effects. Conclusion: The NP alone may give adequate protection against the H1N1 strain of Influenza A.