The aging immune system is more functional than previously believed

In a study published today in the Open Access journal PLOS Pathogens, scientists at McMaster University in Hamilton, Ontario have determined that a specialized class of immune cells, known as T cells, retains its functionality with age and can respond to virus infections with the same vigor as T cells from a young person. This is a valuable finding as it is generally believed that elderly individuals are at increased risk of infection because immunity deteriorates with age.

T cells play an important role in defending the body from virus infections. For a long time, researchers have believed that the elderly were at increased risk of infection due to a lack of T cells. However, new research led by Jonathan Bramson and a team of researchers from McMaster as well as the University of Toronto and the University of Pennsylvania has shown that, in fact, elderly individuals mount perfectly normal immune responses to virus infections. The researchers studied the immune response to 3 different viruses in young individuals and elderly individuals. They found that both the number of virus-fighting T cells and the functionality of the T cells were equivalent in both groups.

This research indicates that as humans age, our bodies retain the ability to mount robust T cell responses to new viruses, while maintaining immunity to viruses we have been exposed to in the past. These results have important implications for vaccination of elderly individuals. Current vaccines for the elderly are not designed to elicit T cells responses and this may explain the failure of the annual influenza vaccine to provide effective protection of elderly individuals. Ultimately, this research indicates that vaccines specifically designed to generate T cell immunity may be more effective at protecting elderly individuals from virus infections.

FINANCIAL DISCLOSURE: This work was funded by the National Institutes of Health and the Canadian Institutes for Health Research. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

COMPETING INTERESTS: The authors have declared that no competing interests exist.

PLEASE ADD THIS LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.plos.org/10.1371/journal.ppat.1003076 (link will go live upon embargo lift)

CITATION: Lelic A, Verschoor CP, Ventresca M, Parsons R, Evelegh C, et al. (2012) The Polyfunctionality of Human Memory CD8+ T Cells Elicited by Acute and Chronic Virus Infections Is Not Influenced by Age. PLoS Pathog 8(12): e1003076. doi:10.1371/journal.ppat.1003076

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Gina Alvino
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plospathogens@plos.org

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