Aging brings about a selective decline in the numbers and function of T cells - a type of white blood cell involved in the immune system's response to infection - and T cells that survive the longest may better protect against infections such as the flu, according to a study led by researchers from the University of Arizona College of Medicine - Tucson. The finding may lead to targeting these cells with vaccinations that increase their number and improve protection against disease in older adults.
The study results are reported in the Aug. 1 Early Edition issue of the Proceedings of the National Academy of Sciences
. The article, "Non-random attrition of the naďve CD8+ T-cell pool with aging governed by TCR:pMHC interactions," is available at www.pnas.org/papbyrecent.shtml
The decline in immune function with age is viewed as the most important contributing factor to older adults' increased susceptibility to infections and decreased responses to vaccinations. Improving T cell function can result in improved immunity.
"We have discovered that aging brings about selective attrition of those T cells that defend us against new infections that we have not encountered before. Not all T cells age the same and the ones that will survive the longest have special features that may allow them to best protect against infections such as flu," says study senior author Janko Nikolich-Žugich, MD, PhD, chairman of the Department of Immunobiology, co-director of the Arizona Center on Aging, and Elizabeth Bowman Professor in Medical Research at the UA College of Medicine, and a member of the UA BIO5 Institute. "We now know that there are a few good cells that can be targeted by vaccination to expand their numbers and achieve protection.Finding ways to expand them is our next and final challenge, and our team at the Arizona Center on Aging should be able to achieve that in the next few years."