Intranasal Immunization with Pressure Inactivated Avian Influenza Elicits Cellular and Humoral Responses in Mice

Abstract

Influenza viruses pose a serious global health threat, particularly in light of newly emerging strains, such as the avian influenza H5N1 and H7N9 viruses. Vaccination remains the primary method for preventing acquiring influenza or for avoiding developing serious complications related to the disease. Vaccinations based on inactivated split virus vaccines or on chemically inactivated whole virus have some important drawbacks, including changes in the immunogenic properties of the virus. To induce a greater mucosal immune response, intranasally administered vaccines are highly desired as they not only prevent disease but can also block the infection at its primary site. To avoid these drawbacks, hydrostatic pressure has been used as a potential method for viral inactivation and vaccine production. In this study, we show that hydrostatic pressure inactivates the avian influenza A H3N8 virus, while still maintaining hemagglutinin and neuraminidase functionalities. Challenged vaccinated animals showed no disease signs (ruffled fur, lethargy, weight loss, and huddling). Similarly, these animals showed less Evans Blue dye leakage and lower cell counts in their bronchoalveolar lavage fluid compared with the challenged non-vaccinated group. We found that the whole inactivated particles were capable of generating a neutralizing antibody response in serum, and IgA was also found in nasal mucosa and feces. After the vaccination and challenge we observed Th1/Th2 cytokine secretion with a prevalence of IFN-γ. Our data indicate that the animals present a satisfactory immune response after vaccination and are protected against infection. Our results may pave the way for the development of a novel pressure-based vaccine against influenza virus.

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

“…The ideal vaccine stimulates serum IgG and mucosal IgA production, a cytokine response, and a longer-lasting immune response (25). We found that mice vaccinated with HA1–2-fliC and HA1–2-PEI developed a rapid systemic immune response in serum and robust mucosal immune response in the nasal cavity and bronchial alveoli.…”

“…HA1–2-fliC and PEI-supplemented vaccines induced higher numbers of spleen cells to secrete IL-4 and IFN-γ, whereas PEI induced more cells to secrete IL-4. In mice, IFN-γ and IL-4 are associated with Th1 and Th2 responses, respectively (25, 29). Thus, our data indicate that mice vaccinated with HA1–2-fliC exhibited a balanced Th1/Th2 response, and HA1–2-PEI exhibited a Th2-biased response.…”

Enhanced humoural and cellular immune responses to influenza H7N9 antigen HA1–2 fused with flagellin in chickens

“…The ideal vaccine stimulates not only serum IgG production but also the cellular response [ 30 ]. T cells play an important role in protection against various strains of influenza virus [ 31 ].…”

Histological and anatomical structure of the nasal cavity of Bama minipigs

“…Intranasal immunization is a non-invasive and easily administered treatment that allows for rapid absorption of antigens, thereby protecting against respiratory infections [41]. In addition, although both intranasal and oral administration elicit immune responses, the intranasal delivery route produces a superior immune effect [42].…”