Research Spotlight: Oct 2010
U of A researchers find amino acid that can help fight infections
By Hayley Dunning
A University of Alberta study has found that the ability to fight infection could be controlled in part by one amino acid, a crucial finding that could have major implications for malnourished individuals, intensive care patients and even arthritis sufferers.
Richard Lamb, associate professor from the department of oncology at the Cross Cancer Institute, along with his postdoctoral fellow Virginie Mieulet, identified the amino acid arginine as a critical component of the immune response, drawing infection-fighting macrophage cells to the site of infection.
Lamb and Mieulet’s study induced fasting in mice and then introduced amino acids while testing their response to a substance that mimics bacterial infection. The mice that received arginine—as opposed to other amino acids—were better able to fight off infection. "This is pretty exciting because it suggests there's a real role of arginine in modulating this response to bacteria,” says Lamb. “The only question then is ... is it happening during fasting of malnourished human beings?"
The work is still in the very early stages, but Lamb thinks the implications could be far-reaching. For example, people in intensive care units, who are much more susceptible to infection, may benefit from arginine supplements. Conversely, too much arginine during infection could provoke an overreaction from the body, causing inflammatory reactions like arthritis. Lamb suggests that withdrawal from eating while fighting infection could be a protective response by our body to prevent dangerous overreaction.
Similarly, this discovery could have implications for millions of people living in the developing world who are malnourished and more vulnerable to infection. Arginine is commonly found in red meat and other proteins—items that are often absent in malnourished people’s diets.
Lamb admits there's still a long way to go before any of these possible effects are understood in any detail but is positive about the implications of a study that derived from a series of unexpected results.
Initially, Lamb, a cancer researcher, was investigating how a biological pathway associated with normal cell growth can get out of control, leading to cancerous tumours, when a different pathway link with the body’s response to bacteria came to his attention. Although the role of arginine in immune response was a departure from his normal work, it was a problem that begged to be solved, and Lamb’s lab, at least in part, had the power to solve it.
"That's something you have to be very aware of in science,” says Lamb. “[You have to be] very prepared to be wrong about things, and admit you're wrong about things, and focus on the things that are real. And these are often the controls in the experiments that you do, that turn out to be much more interesting than your fancy idea."
Lamb noted that, like the original study that included work from a number of labs across Europe, any further results will require collaboration between many experts before any real-world benefits can be applied.