Researchers at Oregon Health & Science University have
uncovered new information about the body’s immune
system in a study that suggests new strategies may be
in order for protecting the country’s aging population
against disease. The research is published in the
current edition of the Proceedings of the National
Academy of Sciences.
The research focused on an important component of the
body’s immune system, a certain type of white blood
cell called naïve 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 naïve T-cells how to
recognize germs and prepare the body for fighting
infectious diseases at a later date. Previous research
shows that an individual’s supply of naïve 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
naïve 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, naïve T-cells divide very
slowly in our bodies. This helps maintain sufficient
numbers of naïve T-cells while we are young. As we
age, naïve 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 naïve T-cells to
dwindle over time. Our data show that once the number
of naïve T-cells drops below a critical point, the
rapidly dividing naïve cells are very short lived.
Based on this finding and other information, research
suggests that some of the aging Americans may be
better protected against disease by finding a way to
jumpstart production of new naïve T-cells instead of
through revaccination.”
Nikolich-Zugich and his colleagues are now working on
methods to encourage the body to restart production of
naïve T-cells.
“Even a slight boost in the number of these important
T-cells could protect an aging person against disease
for several years,” explained Nikolich-Zugich.
The research was funded by U.S. Public Health Service
Awards, the National Institute on Aging, a component
of the National Institutes of Health; and Oregon
National Primate Research Center funds.
Source:-Oregon
Health & Science University
Published on the 4th January 2008
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