Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infection

IntroductionThe H9N2 avian influenza virus, although not highly pathogenic, still poses ongoing risks to poultry health and food security due to its ability to resist vaccines and its potential to spread to humans.MethodsThis study investigated the effects of baicalin, a flavonoid derived from Scute...

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Main Authors: Zhenyi Liu, Haotong Guo, Yan Zhi, Xiaorui Jiang, Qian Zhang
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Immunology
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Online Access:https://www.frontiersin.org/articles/10.3389/fimmu.2025.1593691/full
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author Zhenyi Liu
Haotong Guo
Yan Zhi
Xiaorui Jiang
Qian Zhang
author_facet Zhenyi Liu
Haotong Guo
Yan Zhi
Xiaorui Jiang
Qian Zhang
author_sort Zhenyi Liu
collection DOAJ
description IntroductionThe H9N2 avian influenza virus, although not highly pathogenic, still poses ongoing risks to poultry health and food security due to its ability to resist vaccines and its potential to spread to humans.MethodsThis study investigated the effects of baicalin, a flavonoid derived from Scutellaria baicalensis, on respiratory mucosal immunity during H9N2 infection. In vitro experiments were conducted using MLE-12 alveolar epithelial cells, and in vivo evaluations were performed in a mouse model of H9N2 infection.ResultsBaicalin treatment enhanced the expression of antiviral proteins Mx1 and PKR in a dose- and time-dependent manner, helping to counteract the virus’s suppression of these defense proteins. In addition to strengthening this epithelial barrier, baicalin has both antiviral and immune-regulating effects: it directly blocks viral replication and helps restore the CD4+/CD8+ T cell ratio in H9N2-infected mice. Most importantly, baicalin reduces lung damage and spleen shrinkage while keeping the immune system balanced. These results show that baicalin enhances mucosal antiviral defenses by simultaneously regulating innate antiviral pathways (Mx1 and PKR) and restoring adaptive immune balance (CD4+/CD8+ T-cell ratio).DiscussionThese dual protective effects highlight baicalin’s potential as a natural therapeutic strategy for improving mucosal immunity against vaccine-resistant influenza viruses such as H9N2, contributing valuable insights into plant-derived immunomodulatory approaches against emerging zoonotic viral threats.
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issn 1664-3224
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spelling doaj-art-e4a09decb27f4e81966818166a39004f2025-08-20T03:52:43ZengFrontiers Media S.A.Frontiers in Immunology1664-32242025-05-011610.3389/fimmu.2025.15936911593691Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infectionZhenyi Liu0Haotong Guo1Yan Zhi2Xiaorui Jiang3Qian Zhang4College of Animal Science and Technology, Beijing University of Agriculture, Beijing, ChinaCollege of Animal Science and Technology, Beijing University of Agriculture, Beijing, ChinaCollege of Animal Science and Technology, Beijing University of Agriculture, Beijing, ChinaYanTai Yuhuangding Hospital Affiliated to Qingdao University, Yantai, ChinaCollege of Animal Science and Technology, Beijing University of Agriculture, Beijing, ChinaIntroductionThe H9N2 avian influenza virus, although not highly pathogenic, still poses ongoing risks to poultry health and food security due to its ability to resist vaccines and its potential to spread to humans.MethodsThis study investigated the effects of baicalin, a flavonoid derived from Scutellaria baicalensis, on respiratory mucosal immunity during H9N2 infection. In vitro experiments were conducted using MLE-12 alveolar epithelial cells, and in vivo evaluations were performed in a mouse model of H9N2 infection.ResultsBaicalin treatment enhanced the expression of antiviral proteins Mx1 and PKR in a dose- and time-dependent manner, helping to counteract the virus’s suppression of these defense proteins. In addition to strengthening this epithelial barrier, baicalin has both antiviral and immune-regulating effects: it directly blocks viral replication and helps restore the CD4+/CD8+ T cell ratio in H9N2-infected mice. Most importantly, baicalin reduces lung damage and spleen shrinkage while keeping the immune system balanced. These results show that baicalin enhances mucosal antiviral defenses by simultaneously regulating innate antiviral pathways (Mx1 and PKR) and restoring adaptive immune balance (CD4+/CD8+ T-cell ratio).DiscussionThese dual protective effects highlight baicalin’s potential as a natural therapeutic strategy for improving mucosal immunity against vaccine-resistant influenza viruses such as H9N2, contributing valuable insights into plant-derived immunomodulatory approaches against emerging zoonotic viral threats.https://www.frontiersin.org/articles/10.3389/fimmu.2025.1593691/fullbaicalinH9N2 avnia influenza virusrespiratory mucosal immunityantiviral proteinsMX1PKR
spellingShingle Zhenyi Liu
Haotong Guo
Yan Zhi
Xiaorui Jiang
Qian Zhang
Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infection
Frontiers in Immunology
baicalin
H9N2 avnia influenza virus
respiratory mucosal immunity
antiviral proteins
MX1
PKR
title Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infection
title_full Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infection
title_fullStr Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infection
title_full_unstemmed Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infection
title_short Baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and T-cell homeostasis during H9N2 infection
title_sort baicalin enhances respiratory mucosal immunity by modulating antiviral protein expression and t cell homeostasis during h9n2 infection
topic baicalin
H9N2 avnia influenza virus
respiratory mucosal immunity
antiviral proteins
MX1
PKR
url https://www.frontiersin.org/articles/10.3389/fimmu.2025.1593691/full
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