Moderate exercise early after influenza virus infection reduces the Th1 inflammatory response in lungs of mice.
We have previously shown that moderate exercise significantly increased survival after influenza virus (A/PR/8/34) infection in mice. We hypothesized that this brief duration of exercise would either increase innate immune defences and/or shift the immune response from a Th1 inflammatory to a Th2 anti-inflammatory response resulting in decreased lung pathology. Adult male BALB/cByJ mice (5-6 months old) were infected with 50 microL of A/PR/8/34 virus (40HAU) intranasally and randomized to either an exercise (EX) or sedentary (SED) group. EX mice performed 20-30 min of moderate exercise (8-12 m/min) on a motorized treadmill 4 hr post-infection and then exercised similarly for 4 consecutive days. SED mice were exposed to similar environmental conditions but did not exercise. Mice from both EX and SED groups were sacrificed 1, 3, or 5 days post-infection (p.i.) and lungs, mediastinal lymph nodes (MLNs) and spleens were harvested. EX significantly reduced total cellular infiltration and IFN-gamma gene expression in lungs at Days 3 and 5 p.i. and there was a qualitative shift in the expression of cytokines in the lung from a Th1 to a Th2 response. There was also a tendency toward a reduction in influenza M1 protein mRNA expression. There was no difference in IFN-beta protein levels between groups. These data suggest that moderate exercise when applied early after infection shifts the immune response away from a Th1 profile in mice infected with influenza virus. This exercise-induced shift in immune response may be responsible for improved survival after influenza virus infection.
Lowder
Thomas
T
Department of Kinesiology, University of Illinois and Urbana-Champaign, Urbana, IL 61801, USA.
Padgett
David A
DA
Woods
Jeffrey A
JA
D000818:Animals; D029521:Alphainfluenzavirus / Q000276:immunology / Q000502:physiology; D007371:Interferon-gamma / Q000378:metabolism; D008168:Lung / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000276:immunology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011014:Pneumonia / Q000276:immunology*; D011897:Random Allocation; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology
D007371:Interferon-gamma