Intranasal administration of Lactobacillus rhamnosus GG protects mice from H1N1 influenza virus infection by regulating respiratory immune responses.
OBJECTIVE
To investigate whether intranasal Lactobacillus administration protects host animals from influenza virus (IFV) infection by enhancing respiratory immune responses in a mouse model.


RESULTS
After 3 days of intranasal exposure to Lactobacillus rhamnosus GG (LGG), BALB/c mice were infected with IFV A/PR/8/34 (H1N1). Mice treated with LGG showed a lower frequency of accumulated symptoms and a higher survival rate than control mice (P < 0.05). The YAC-1 cell-killing activity of lung cells isolated from mice treated with LGG was significantly greater than those isolated from control mice (P < 0.01). Intranasal administration of LGG significantly increased mRNA expression of interleukin (IL)-1 beta, tumour necrosis factor (TNF) and monocyte chemotactic protein (MCP)-1 (P < 0.01).


CONCLUSIONS
These results suggest that intranasal administration of LGG protects the host animal from IFV infection by enhancing respiratory cell-mediated immune responses following up-regulation of lung natural killer (NK) cell activation.


CONCLUSIONS
We have demonstrated that probiotics might protect host animals from viral infection by stimulating immune responses in the respiratory tract.
Harata
G
G
Technical Research Laboratory, Takanashi Milk Products Co., Ltd.,Yokohama, Kanagawa, Japan.
He
F
F
Hiruta
N
N
Kawase
M
M
Kubota
A
A
Hiramatsu
M
M
Yausi
H
H
D000281:Administration, Intranasal; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology / Q000502:physiology*; D007251:Influenza, Human / Q000235:genetics / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D053583:Interleukin-1beta / Q000235:genetics / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology; D052201:Lacticaseibacillus rhamnosus / Q000276:immunology*; D008168:Lung / Q000276:immunology / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D012137:Respiratory System / Q000276:immunology* / Q000821:virology
D053583:Interleukin-1beta