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

How defeating THOR could bring a hammer down on cancer

December 14, 2017
It turns out Thor, the Norse god of thunder and the Marvel superhero, has special powers when it comes to cancer too.

Researchers track muscle stem cell dynamics in response to injury and aging

December 14, 2017
A new study led by researchers at Sanford Burnham Prebys Medical Discovery Institute (SBP) describes the biology behind why muscle stem cells respond differently to aging or injury. The findings, published in Cell Stem Cell, ...

'Human chronobiome' study informs timing of drug delivery, precision medicine approaches

December 13, 2017
Symptoms and efficacy of medications—and indeed, many aspects of the human body itself—vary by time of day. Physicians tell patients to take their statins at bedtime because the related liver enzymes are more active during ...

Estrogen discovery could shed new light on fertility problems

December 12, 2017
Estrogen produced in the brain is necessary for ovulation in monkeys, according to researchers at the University of Wisconsin-Madison who have upended the traditional understanding of the hormonal cascade that leads to release ...

Time of day affects severity of autoimmune disease

December 12, 2017
Insights into how the body clock and time of day influence immune responses are revealed today in a study published in leading international journal Nature Communications. Understanding the effect of the interplay between ...

3-D printed microfibers could provide structure for artificially grown body parts

December 12, 2017
Much as a frame provides structural support for a house and the chassis provides strength and shape for a car, a team of Penn State engineers believe they have a way to create the structural framework for growing living tissue ...

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.