Human Immune Responses Elicited by an Intranasal Inactivated H5 Influenza Vaccine

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Microbiol Immunol. 2020 Jan 20. doi: 10.1111/1348-0421.12775. [Epub ahead of print] Human Immune Responses Elicited by an Intranasal Inactivated H5 Influenza Vaccine.

Ainai A^1,2, van Riet E^1,2, Ito R¹, Ikeda K¹, Senchi K¹, Suzuki T¹, Tamura SI¹, Asanuma H^1,2, Odagiri T², Tashiro M², Kurata T¹, Multihartina P³, Setiawaty V³, Andriana Pangesti KN³, Hasegawa H^1,2,4.
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Abstract

Intranasally administered influenza vaccines could be more effective than injected vaccines, since intranasal vaccination can induce virus-specific IgA antibodies in the upper respiratory tract, which is the initial site of infection. In the current study, immune responses elicited by an intranasal inactivated H5 influenza vaccine were evaluated in healthy H5 influenza virus-naive individuals. Three doses of intranasal inactivated whole-virion H5 influenza vaccine induced strong neutralizing nasal IgA and serum IgG antibodies. In addition, a mucoadhesive excipient, carboxy-vinyl polymer (CVP), had a notable impact on the induction of nasal IgA antibody responses but not serum IgG antibody responses. The nasal hemagglutinin (HA)-specific IgA antibody responses clearly correlated with mucosal neutralizing antibody responses, indicating that measurement of nasal HA-specific IgA titers could be used as a surrogate for the mucosal antibody response. Furthermore, increased numbers of plasma cells and vaccine antigen-specific helper T (Th) cells in the peripheral blood were observed after vaccination, suggesting that peripheral blood biomarkers may also be used to evaluate the intranasal vaccine-induced immune response. However, peripheral blood immune cell responses correlated with neutralizing antibody titers in serum samples but not in nasal wash samples. Thus, analysis of the peripheral blood immune response could be a surrogate for the systemic immune response to intranasal vaccination but not for the mucosal immune response. The current study suggests the clinical potential of intranasal inactivated vaccines against H5 influenza viruses and highlights the need to develop novel means to evaluate intranasal vaccine-induced mucosal immune responses. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.


KEYWORDS:

HA-specific nasal IgA; immunological surrogates; inactivated whole-virion influenza vaccine; influenza A(H5N1) virus; intranasal inactivated influenza vaccine

PMID: 31957054 DOI: 10.1111/1348-0421.12775