Mucosal and Systemic Immune Responses to Influenza H7N9 Antigen HA1–2 Co-Delivered Intranasally with Flagellin or Polyethyleneimine in Mice and Chickens

摘要: Consecutive cases of human infection with H7N9 influenza viruses since 2013 in China have prompted efforts to develop an effective treatment. Subunit vaccines introduced by intranasal administration can block at its primary site; flagellin (fliC) and polyethyleneimine (PEI) been shown be potent adjuvants. We previously generated the hemagglutinin (HA)1-2-fliC fusion protein consisting globular head domain (HA1-2; amino acids 62-284) HA fused Salmonella typhimurium fliC. In present study, we investigated effectiveness both PEI as mucosal adjuvants for subunit vaccine. Mice immunized intranasally HA1-2-fliC HA1-2-PEI showed higher HA1-2-specific immunoglobulin (Ig)G IgA titers serum, nasal wash, bronchial alveolar lavage fluid. Moreover, splenocyte activation proliferation number interferon (IFN)-γ- interleukin (IL)-4-producing splenocytes were markedly increased fliC groups; latter, there more cells secreting IL-4 than IFN-γ, suggesting that induced T helper type (Th)1 Th2 immune responses, Th2-biased consistent serum antibody isotype pattern (IgG1/IgG2a ratio). Furthermore, virus challenge was performed a chicken model. The results chickens receiving adjuvant vaccine exhibited robust responses leading significant reduction viral loads throat cloaca compared only HA1-2. These findings provide basis development HA1-2 vaccines.