Children are born with the ability to make antibodies, proteins that fight infection. However, they do not respond to immunization in the same way as adults and several aspects of the immune system are distinctly different. Researchers at the Oklahoma Medical Research Foundation have found another difference, one that may be important to development of the immune system during fetal life
http://www.newswise.com/articles/2001/10/IMMUNLGY.PH2.html
19-Oct-01
PITTSBURGH, Pa. -- Children are born
with the ability to make antibodies, proteins that fight infection. However,
they do not respond to immunization in the same way as adults and several
aspects of the immune system are distinctly different. Researchers at the
Oklahoma Medical Research Foundation (OMRF) have found another difference,
one that may be important to development of the immune system during fetal
life.
Lymphocytes, the cells responsible
for making antibodies, are made in large numbers throughout life within
bone marrow. A variety of evidence suggests that this process is regulated
in a negative way by hormones, including estrogen. When estrogen levels
are high, as they are during pregnancy, lymphocyte production is severely
depressed in the mother's bone marrow. It has been a mystery why the high
estrogen concentrations do not also prevent development of the baby's immune
system.
Dr. Hidyea Igarashi and his colleagues
at OMRF may have solved this paradox. Estrogen controls lymphocyte formation,
and thus replenishment of the immune system by binding to hormone receptors
found only in rare "precursors" within adult bone marrow. Igarashi found
that the receptors were not expressed on corresponding cells of the fetus.
Indeed, the receptors are expressed after birth in experimental animals
and man. By lacking these receptors, the immune system of the fetus is
protected from estrogen and related compounds that might be present in
the environment. It adds to information that various kinds of "stem" cells
may not be the same in fetal and adult life.
Paul W. Kincade, Ph.D., the head
of the research team, will present detailed findings of this research,
"Sex Steroids Regulate Lymphocyte Development in Adults, but not Fetal
Life and Can Be Used to Resolve Early Blood Cell Precursors," at the upcoming
conference, Genomes and Hormones: An Integrative Approach to Gender Differences
in Physiology. The conference is being sponsored by the American Physiological
Society (APS) and will be held October 17-20, 2001, at the Westin Convention
Center, Pittsburgh, PA.
Other investigators in Dr. Kincade's
lab have found that hormones can be used as experimental tools for understanding
how the various types of specialized blood cells are made from stem cells
within bone marrow. His research team's efforts are supported by grants
from the National Institutes of Health (NIH).
The American Physiological Society
(APS) was founded in 1887 to foster basic and applied science, much of
it relating to human health. The Bethesda, MD-based Society has more than
10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals
every year.
Contact: Donna Krupa: 703.527.7357
OR IN THE APS NEWSROOM @ The Westin
Convention Center
Editor's Note: To set up an interview
with Dr. Kincade, please contact Donna Krupa in the APS newsroom 412.281.3700
(The Crawford Room). After newsroom hours call 703.967.2751 (cell), 703.527.7357
(direct dial) or email djkrupa1@aol.com.
© 1995-2001 Newswise
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October 17-20, 2001
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