Scientists Receive Grant to Study How Age Affects Cells' Reaction to Flu Virus

Influenza is the fourth leading cause of death among people 65 and older. Two MSU scientists are examining how age-related changes in cells affect the immune system's ability to fight off the flu.

Elizabeth Gardner

Influenza is the fourth leading cause of death among people 65 and older. Two MSU scientists are examining how age-related changes in cells affect the immune system's ability to fight off the flu.

Elizabeth Gardner, MABR food science and human nutrition researcher, and Sungjin Kim, assistant professor of microbiology and molecular genetics, were awarded a $2 million grant from the National Institutes of Health (NIH) to expand their research.

"The statistics are staggering, and the threat of H1N1 has increased the need to better understand how the body fights the virus,? Gardner said. ?We need to better understand age-related changes in the primary immune responses to acute influenza infections because the immune response decreases with age."

As part of their work, Gardner and Kim have identified the critical role played by natural killer cells in controlling early influenza infections in mice.

Natural killer cells kill virus-infected cells. For example, when a person is infected with influenza, the virus enters the epithelial cells in the lungs and causes illness. Natural killer cells kill the virus-infected epithelial cells and limit the amount of virus that can replicate in the lungs and cause damage.

These results suggest that natural killer cells are essential for early control of influenza infection by the immune system. But the scientists also found that natural killer cells in elderly mice don't kill virus-infected cells. Instead, the virus grows in the lungs and the mice ultimately die from the flu.

The NIH grant will allow Gardner and Kim to study how coaxing the immune system to produce a good natural killer cell response can control early flu infections in vulnerable populations, including older people.

"The prevalence of seasonal influenza and the recent emergence of H1N1 suggest the need to study age-related changes in the primary response to influenza infection," Gardner said. "Older people have a higher risk for infections, cancer, and autoimmune and other diseases, which can be explained, at least in part, by decreased immune function.

"If we apply this theory to humans, it suggests that both older and younger people's ability to mount an early and effective natural killer cell response to influenza infection is vital, especially when vaccine is limited or unavailable," she continued.

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