Scientists Find Genetic Clues to Why Immune System Gets Weaker with Age
Understanding how to maintain strong, healthy immune systems could help many live longer, healthier lives
July 11, 2012 A team of U.S. scientists say they have discovered important insights that explain why our ability to
ward off infection declines with age. They identified genes responsible for this decline by examining fruit flies a model organism often
used to study human biology at different stages of their lives.
They found that a completely different set of genes is responsible for warding off infection at middle age than during
youth. Many of the genes identified are also present in humans, so this study opens doors to understanding genetic interactions that underlie
why older people have more trouble fighting off infections than do younger people.
"We believe we have identified genes that contribute to the age-related deterioration of the immune response to
infection," said Jeff Leips, Ph.D., a researcher involved in the work from the Department of Biological Sciences at the University of
Maryland, Baltimore County.
"Because many of the genes that we have identified also occur in humans, we hope that such knowledge will lead to new
treatments to maintain immune function as we age."
To make this discovery, Leips used fruit flies of different genotypes that were derived from a natural population. Flies
of each genotype were infected with bacteria at two different ages when they were young, at an age equivalent to human teenagers, and when
they were older, in what might be the equivalent to early middle age in humans.
The researchers then measured the ability of the flies to clear the bacterial infection at each age while simultaneously
assessing how the expression of genes responded to infection.
Genes whose variation in expression were associated with the ability to clear the infection were identified for each of
the different ages at the time of infection. Surprisingly, the genes were different -- there was no overlap in the sets of genes associated
with the ability to clear infection across ages.
The research report is in the July 2012 issue of the Genetics Society of America's journal, GENETICS.
"The notion that the genes responsible for immune function are almost entirely different in middle age than in early
adulthood is tantalizing," said Mark Johnston, editor-in-chief of
"As the average age of the U.S. population increases, understanding how to maintain strong, healthy immune systems could
help many of us live longer, healthier lives."
About GENETICS: Since 1916, GENETICS (http://www.genetics.org/)
has covered high quality, original research on a range of topics bearing on inheritance, including population and evolutionary genetics,
complex traits, developmental and behavioral genetics, cellular genetics, gene expression, genome integrity and transmission, and genome and
systems biology. GENETICS, a peer-reviewed, peer-edited journal of the Genetics Society of America, is one of the world's most cited journals
in genetics and heredity.
About GSA: Founded in 1931, the Genetics Society of America (GSA) is the professional membership
organization for scientific researchers, educators, bioengineers, bioinformaticians and others interested in the field of genetics. Its nearly
5,000 members work to advance knowledge in the basic mechanisms of inheritance, from the molecular to the population level. For more
information about GSA, visit
www.genetics-gsa.org. Also follow GSA on Facebook at facebook.com/GeneticsGSA and on Twitter @GeneticsGSA.
CITATION: T. M. Felix, K. A. Hughes, E. A. Stone, J. M. Drnevich, and J. Leips. Age-specific variation in
immune response in Drosophila melanogaster has a genetic basisGenetics July 2012 Volume 191, Issue 3.
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