CD25+ natural regulatory T cells are critical in limiting innate and adaptive immunity and resolving disease following respiratory syncytial virus infection.
Regulatory CD4(+) T cells have been shown to be important in limiting immune responses, but their role in respiratory viral infections has received little attention. Here we observed that following respiratory syncytial virus (RSV) infection, CD4(+) Foxp3(+) CD25(+) natural regulatory T-cell numbers increased in the bronchoalveolar lavage fluid, lung, mediastinal lymph nodes, and spleen. The depletion of CD25(+) natural regulatory T cells prior to RSV infection led to enhanced weight loss with delayed recovery that was surprisingly accompanied by increased numbers of activated natural killer cells in the lung and bronchoalveolar lavage fluid on day 8 postinfection. Increased numbers of neutrophils were also detected within the bronchoalveolar lavage fluid and correlated with elevated levels of myeloperoxidase as well as interleukin-6 (IL-6) and gamma interferon (IFN-gamma). CD25(+) natural regulatory T-cell depletion also led to enhanced numbers of proinflammatory T cells producing IFN-gamma and tumor necrosis factor alpha (TNF-alpha) in the lung. Despite these increases in inflammatory responses and disease severity, the viral load was unaltered. This work highlights a critical role for natural regulatory T cells in regulating the adaptive and innate immune responses during the later stages of lung viral infections.
Lee
Debbie C P
DC
Department of Respiratory Medicine and Centre for Respiratory Infection, National Heart and Lung Institute, Imperial College, St Mary's Campus, Norfolk Place, London W2 1PG, United Kingdom.
Harker
James A E
JA
Tregoning
John S
JS
Atabani
Sowsan F
SF
Johansson
Cecilia
C
Schwarze
Jürgen
J
Openshaw
Peter J M
PJ
D056704:Adaptive Immunity; D000818:Animals; D002460:Cell Line; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D007371:Interferon-gamma / Q000276:immunology; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology; D015850:Interleukin-6 / Q000276:immunology; D008168:Lung / Q000276:immunology / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology* / Q000473:pathology / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000276:immunology / Q000502:physiology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000821:virology
D053645:Interleukin-2 Receptor alpha Subunit; D015850:Interleukin-6; D007371:Interferon-gamma