Rebooting the system: Immune cells repair damaged lung tissues after flu infection

Immuno-fluorescence staining in mouse inflamed lung tissue showing activated airway epithelial cells (green), infiltrating macrophages (red) and cell nuclei (blue). Credit: Image courtesy of Meera Nair, Laurel Monticelli and David Artis, Perelman School of Medicine, University of Pennsylvania

There's more than one way to mop up after a flu infection. Now, researchers from the Perelman School of Medicine at the University of Pennsylvania report in Nature Immunology that a previously unrecognized population of lung immune cells orchestrate the body's repair response following flu infection.

In addition to the looming threat of a deadly , an estimated 200,000 people are hospitalized because of the flu and 36,000 die each year in the US, according to the Centers for Disease Control. However, many influenza-related deaths are not a direct result of the invading virus but instead are linked to the body's failure to effectively repair and restore lung tissues after it has been damaged by the virus. However, the processes that promote lung tissue repair have remained elusive.

In this new report, David Artis, PhD, associate professor of Microbiology; Laurel Monticelli, a PhD student in the Artis lab; and colleagues observed that flu-infected mice without a population of called innate lymphoid cells suffered poor lung function leading to eventual death. The team also found that those innate lymphoid cells produced a growth factor called amphiregulin. Infusion of innate lymphoid cells or amphiregulin to the lungs of infected mice normalized , suggesting that the activation of these cells is central to at lung surfaces.

Notably, the researchers found that innate lymphoid cells don't attack the virus per se, as other immune cells do; rather, they spur the proliferation of cells that line the lung, which aids in wound healing of the lung tissues that have been severely damaged as a result of the viral infection.

Based on these findings, this lung could also promote wound healing following other respiratory infections and possibly drive tissue remodeling in situations of non-infectious and inflammation such as asthma, explains first author Monticelli.

In order to extend these studies to human health, Artis and his team collaborated with researchers at Columbia University to identify a population of innate lymphoid cells that is resident in healthy human lung tissue similar to the cells found in mice. These findings raise the possibility that these cells may also orchestrate repair in humans and that targeting activation of innate lymphoid cells through amphiregulin or other proteins may speed tissue recovery in patients suffering from respiratory illnesses.

"The identification of innate lymphoid cells in the lung, and new studies from multiple research groups illuminating their previously unrecognized functions in diverse disease processes could help in the design of new drugs to prevent or better fight many common infectious or inflammatory diseases," concludes Artis.

add to favorites email to friend print save as pdf

Related Stories

Immune cells protect body from invaders

Feb 07, 2011

So-called barrier sites -- the skin, gut, lung – limit the inner body’s exposure to allergens, pollutants, viruses, bacteria, and parasites. Understanding how the immune system works in these external ...

US researchers identify first human lung stem cell

May 11, 2011

For the first time, researchers at Brigham and Women's Hospital (BWH) have identified a human lung stem cell that is self-renewing and capable of forming and integrating multiple biological structures of the lung including ...

Lung cancer cells activate inflammation to induce metastasis

Dec 31, 2008

A research team from the University of California, San Diego School of Medicine has identified a protein produced by cancerous lung epithelial cells that enhances metastasis by stimulating the activity of inflammatory cells. ...

Recommended for you

Among gut microbes, strains, not just species, matter

1 hour ago

A large community of microorganisms calls the human digestive tract home. This dynamic conglomerate of microscopic life forms - the gut microbiome - is vital to how people metabolize various nutrients in ...

Scientists develop compound to fight MRSA

1 hour ago

Microbiologists and chemists at the University of South Florida have developed and patented a synthetic compound that has shown antibiotic action against methicillin resistant Staphylococcus aureus, also k ...

Hydrogen sulfide could help lower blood pressure

3 hours ago

A gas that gives rotten eggs their distinctive odour could one day form the basis of new cardiovascular therapies. Research has indicated that a new compound, called AP39, which generates minute quantities ...

Researchers design tailored tissue adhesives

7 hours ago

After undergoing surgery to remove diseased sections of the colon, up to 30 percent of patients experience leakage from their sutures, which can cause life-threatening complications.

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.