Study reveals flu-fighting role for well-known immune component

June 26, 2012

University of Georgia scientists have discovered a new flu-fighting role for a well-known component of the immune system. Kimberly Klonowski, assistant professor of cellular biology in the UGA Franklin College of Arts and Sciences, and her colleagues found that administering a cell-signaling protein known as IL-15 to mice infected with influenza reduces their peak viral load by nearly three times.

"We gave the IL-15 intranasally and found that it enhanced the movement of the immune system's and into the lung airways," said Klonowski, whose findings were recently published in the journal . "As a result, the animals that received it cleared the virus faster than the control group."

Klonowski cautioned that the protein is only effective against influenza for a defined period of time immediately following infection, which would make its use as a flu treatment difficult to implement. She added that IL-15 has been tested as a vaccine-booster, or adjuvant, in other such as HIV, monkey pox and ; understanding its mechanism of action is essential to maximizing its effectiveness in these contexts.

IL-15 was discovered nearly 20 years ago and is part of a group of known as interleukins. Klonowski noted until recently, however, its primary role was thought to be the maintenance of immune . Yet Klonowski and her colleagues found that concentrations of the protein surge in the respiratory tract in response to influenza infections, which led them to hypothesize that it also might play a role in controlling the virus.

The scientists devised a series of experiments in mice to discern the role of IL-15 in the immune response. It turns out that IL-15 is one of the body's critical first responders during .

First, the scientists blocked the action of IL-15 in mice infected with influenza and found that the number of natural killer cells was reduced 20-fold at the site of infection in comparison with the control group, which received a placebo. Next, scientists administered IL-15 into the airways of mice infected with influenza and found that these mice had three times more natural killer cells than the control group. In addition, their peak decreased by nearly three times.

Klonowski said that despite what their name might suggest, natural killer cells really aren't the most effective components of the immune system. They do indeed kill infected cells, but not in numbers great enough to completely eradicate infection. CD8 T cells that arrive later in the immune response are the ones that clear the infection, riding in like a cavalry to save the day. Klonowski's study suggests that CD8 T cells require the initial presence of natural killer cells, which send some still-unknown signal that subsequently attracts CD8 T cells to the infection site. Her study found that without the presence of IL-15 and the natural killer cells it recruits, the cavalry never makes it to the site of the battle in the respiratory tract.

The researchers are now working to identify the molecular signals that the natural killer cells send with the ultimate goal of directing CD8 T cells more rapidly and precisely to the site of infection. "Even though this paper deals with natural killer cells, we are still really focused on the CD8 T cells, because they're the cell population that is required for complete viral clearance," she said.

Explore further: Adjuvant combo shows potential for universal influenza vaccine

More information: www.plosone.org/article/info%3 … journal.pone.0037539

Related Stories

Adjuvant combo shows potential for universal influenza vaccine

June 8, 2011
Researchers at National Jewish Health have discovered how to prime a second arm of the immune system to potentially boost influenza vaccine effectiveness. A combination of two adjuvants, chemicals used to boost the effectiveness ...

Surprising role for suppressive cytokine in antiviral immune responses

September 15, 2011
(Medical Xpress) -- A molecule normally implicated in restraining immune responses is also capable of stimulating defences against virus infection, according to new research, by promoting the survival of a population of immune ...

Scientists discover way to amp up power of killer T cells

May 10, 2011
Researchers with UCLA's Jonsson Comprehensive Cancer Center have discovered a way to amp up the power of killer T-cells, called CD8 cells, making them more functional for longer periods of time and boosting their ability ...

How to rescue the immune system: Study could lead to novel therapy for cancer

February 26, 2012
In a study published in Nature Medicine, Loyola researchers report on a promising new technique that potentially could turn immune system killer T cells into more effective weapons against infections and possibly cancer.

Recommended for you

Bio-inspired materials give boost to regenerative medicine

August 18, 2017
What if one day, we could teach our bodies to self-heal like a lizard's tail, and make severe injury or disease no more threatening than a paper cut?

Female mouse embryos actively remove male reproductive systems

August 17, 2017
A protein called COUP-TFII determines whether a mouse embryo develops a male reproductive tract, according to researchers at the National Institutes of Health and their colleagues at Baylor College of Medicine, Houston. The ...

Two-step process leads to cell immortalization and cancer

August 17, 2017
A mutation that helps make cells immortal is critical to the development of a tumor, but new research at the University of California, Berkeley suggests that becoming immortal is a more complicated process than originally ...

New Pathology Atlas maps genes in cancer to accelerate progress in personalized medicine

August 17, 2017
A new Pathology Atlas is launched today with an analysis of all human genes in all major cancers showing the consequence of their corresponding protein levels for overall patient survival. The difference in expression patterns ...

New technique overcomes genetic cause of infertility

August 17, 2017
Scientists have created healthy offspring from genetically infertile male mice, offering a potential new approach to tackling a common genetic cause of human infertility.

Are stem cells the link between bacteria and cancer?

August 17, 2017
Gastric carcinoma is one of the most common causes of cancer-related deaths, primarily because most patients present at an advanced stage of the disease. The main cause of this cancer is the bacterium Helicobacter pylori, ...

0 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.