Synthetic toll-like receptor 7 agonist as a conjugated adjuvant enhances the Th1 type immunogenicity of influenza virus vaccine

Vaccination, one of the most effective and cost-efficient strategy in preventing and controlling influenza virus infection, also has poorly immunogenicity and side effects. Thus, adjuvants are employed to augment the immune response and overcome the drawbacks of vaccine. Here, we present a novel Toll-like receptor agonist (SZU101, T7) to evaluate the adjuvanticity for inactivated H1N1 influenza vaccines. Chemical conjugation of T7 agonist with Flu (Flu-T7) significantly increased the release of IFN-γ, IL-12, IL-6 and TNF-α in mouse lymphocytes in vitro. Immunization with Flu-T7 elicited a more potent Th1-polarized immune response, represented by higher IgG2a titers compared to Flu alone. More importantly, immunization with Flu-T7 had no adverse effects. These observations have significant implications for the development of new and promising alternative adjuvant againstinactivated H1N1 influenza vaccines.