Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 Infection

ABSTRACT The gut microbiota plays a critical role in the induction of adaptive immune responses to influenza virus infection. However, the role of nasal bacteria in the induction of the virus-specific adaptive immunity is less clear. Here, we found that disruption of nasal bacteria by intranasal app...

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Main Authors: Minami Nagai, Miyu Moriyama, Takeshi Ichinohe
Format: Article
Language:English
Published: American Society for Microbiology 2021-08-01
Series:mBio
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/mBio.01598-21
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author Minami Nagai
Miyu Moriyama
Takeshi Ichinohe
author_facet Minami Nagai
Miyu Moriyama
Takeshi Ichinohe
author_sort Minami Nagai
collection DOAJ
description ABSTRACT The gut microbiota plays a critical role in the induction of adaptive immune responses to influenza virus infection. However, the role of nasal bacteria in the induction of the virus-specific adaptive immunity is less clear. Here, we found that disruption of nasal bacteria by intranasal application of antibiotics before influenza virus infection enhanced the virus-specific antibody response in a MyD88-dependent manner. Similarly, disruption of nasal bacteria by lysozyme enhanced antibody responses to intranasally administered influenza virus hemagglutinin (HA) vaccine in a MyD88-dependent manner, suggesting that intranasal application of antibiotics or lysozyme could release bacterial pathogen-associated molecular patterns (PAMPs) from disrupted nasal bacteria that act as mucosal adjuvants by activating the MyD88 signaling pathway. Since commensal bacteria in the nasal mucosal surface were significantly lower than those in the oral cavity, intranasal administration of HA vaccine alone was insufficient to induce the vaccine-specific antibody response. However, intranasal supplementation of cultured oral bacteria from a healthy human volunteer enhanced antibody responses to an intranasally administered HA vaccine. Finally, we demonstrated that oral bacteria combined with an intranasal vaccine protect from influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our results reveal the role of nasal bacteria in the induction of the virus-specific adaptive immunity and provide clues for developing better intranasal vaccines. IMPORTANCE Intranasal vaccination induces the nasal IgA antibody which is protective against respiratory viruses, such as influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, understanding how mucosal immune responses are elicited following viral infection is important for developing better vaccines. Here, we focused on the role of nasal commensal bacteria in the induction of immune responses following influenza virus infection. To deplete nasal bacteria, we intranasally administered antibiotics to mice before influenza virus infection and found that antibiotic-induced disruption of nasal bacteria could release bacterial components which stimulate the virus-specific antibody responses. Since commensal bacteria in nasal mucosa were significantly lower than those in the oral cavity, intranasal administration of split virus vaccine alone was insufficient to induce the vaccine-specific antibody response. However, intranasal supplementation of cultured oral bacteria from a healthy human volunteer enhanced antibody responses to the intranasally administered vaccine. Therefore, both integrity and amounts of nasal bacteria may be critical for an effective intranasal vaccine.
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spelling doaj.art-fc326cd3ad2c47479886d603cebf136d2022-12-21T19:57:42ZengAmerican Society for MicrobiologymBio2150-75112021-08-0112410.1128/mBio.01598-21Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 InfectionMinami Nagai0Miyu Moriyama1Takeshi Ichinohe2Division of Viral Infection, Department of Infectious Disease Control, International Research Center for Infectious Diseases, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, JapanDivision of Viral Infection, Department of Infectious Disease Control, International Research Center for Infectious Diseases, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, JapanDivision of Viral Infection, Department of Infectious Disease Control, International Research Center for Infectious Diseases, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, JapanABSTRACT The gut microbiota plays a critical role in the induction of adaptive immune responses to influenza virus infection. However, the role of nasal bacteria in the induction of the virus-specific adaptive immunity is less clear. Here, we found that disruption of nasal bacteria by intranasal application of antibiotics before influenza virus infection enhanced the virus-specific antibody response in a MyD88-dependent manner. Similarly, disruption of nasal bacteria by lysozyme enhanced antibody responses to intranasally administered influenza virus hemagglutinin (HA) vaccine in a MyD88-dependent manner, suggesting that intranasal application of antibiotics or lysozyme could release bacterial pathogen-associated molecular patterns (PAMPs) from disrupted nasal bacteria that act as mucosal adjuvants by activating the MyD88 signaling pathway. Since commensal bacteria in the nasal mucosal surface were significantly lower than those in the oral cavity, intranasal administration of HA vaccine alone was insufficient to induce the vaccine-specific antibody response. However, intranasal supplementation of cultured oral bacteria from a healthy human volunteer enhanced antibody responses to an intranasally administered HA vaccine. Finally, we demonstrated that oral bacteria combined with an intranasal vaccine protect from influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our results reveal the role of nasal bacteria in the induction of the virus-specific adaptive immunity and provide clues for developing better intranasal vaccines. IMPORTANCE Intranasal vaccination induces the nasal IgA antibody which is protective against respiratory viruses, such as influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, understanding how mucosal immune responses are elicited following viral infection is important for developing better vaccines. Here, we focused on the role of nasal commensal bacteria in the induction of immune responses following influenza virus infection. To deplete nasal bacteria, we intranasally administered antibiotics to mice before influenza virus infection and found that antibiotic-induced disruption of nasal bacteria could release bacterial components which stimulate the virus-specific antibody responses. Since commensal bacteria in nasal mucosa were significantly lower than those in the oral cavity, intranasal administration of split virus vaccine alone was insufficient to induce the vaccine-specific antibody response. However, intranasal supplementation of cultured oral bacteria from a healthy human volunteer enhanced antibody responses to the intranasally administered vaccine. Therefore, both integrity and amounts of nasal bacteria may be critical for an effective intranasal vaccine.https://journals.asm.org/doi/10.1128/mBio.01598-21mucosal immunityintranasal vaccineadjuvantSARS-CoV-2
spellingShingle Minami Nagai
Miyu Moriyama
Takeshi Ichinohe
Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 Infection
mBio
mucosal immunity
intranasal vaccine
adjuvant
SARS-CoV-2
title Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 Infection
title_full Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 Infection
title_fullStr Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 Infection
title_full_unstemmed Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 Infection
title_short Oral Bacteria Combined with an Intranasal Vaccine Protect from Influenza A Virus and SARS-CoV-2 Infection
title_sort oral bacteria combined with an intranasal vaccine protect from influenza a virus and sars cov 2 infection
topic mucosal immunity
intranasal vaccine
adjuvant
SARS-CoV-2
url https://journals.asm.org/doi/10.1128/mBio.01598-21
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AT takeshiichinohe oralbacteriacombinedwithanintranasalvaccineprotectfrominfluenzaavirusandsarscov2infection