OHSU research suggests new strategy for protecting aging Americans against infectio...( PORTLAND Ore. Researchers at Oregon...),Health

PORTLAND, Ore. Researchers at Oregon Health & Science University have uncovered new information about the bodys immune system in a study that suggests new strategies may be in order for protecting the countrys aging population against disease. The research is published in the current edition of the Proceedings of the National Academy of Science.

The research focused on an important component of the bodys immune system, a certain type of white blood cell called nave T-cells. These cells are called naive because they have no experience of encountering germs. However, once they encounter germs, they learn and adapt to become strong defenders of the organism. The cells play an important role in the vaccination process because vaccines, which contain either weakened or dead viruses, teach nave T-cells how to recognize germs and prepare the body for fighting infectious diseases at a later date. Previous research shows that an individuals supply of nave T-cells diminishes over their lifetime, meaning that in old age a person is more susceptible to infections such as the flu.

Our research identified one actual process by which nave T-cells are lost later in life, explained Janko Nikolich-Zugich, Ph.D., a senior scientist at the OHSU Vaccine and Gene Therapy Institute and the Oregon National Primate Research Center and a professor of molecular microbiology and immunology in the OHSU School of Medicine.

Throughout our lives, nave T-cells divide very slowly in our bodies. This helps maintain sufficient numbers of nave T-cells while we are young. As we age, nave T-cells are lost and the remaining ones speed up their division to make up for the losses in their numbers. Interestingly, after a certain point, this actually causes the numbers of nave T-cells to dwindle over time. Our data shows that once the number of nave T-cells drops below a critical point, the rapidly dividing nave cells are very short lived. Based on this finding and other in
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