Research
Immune System Boosting
National Jewish Researchers First To Identify Component
In Thymus Positively Selects T Cells
7-22-1999
DENVER-Researchers at National Jewish Medical and Research
Center have identified what T cells “see”
in a normal thymus that controls the development of
functional or immune-system aggressive T cells, according
to today’s issue of the journal Immunity.
“This
is the first time anybody has described what T cells
really ‘see’ when they are positively selected
in the thymus,” said Uwe Staerz, M.D., Ph.D.,
a National Jewish researcher who studies the immune
system.
This
research helps expand the understanding of how the immune
system develops. In the future, this research may help
people who have cancer, because those with cancer don’t
have fully functional immune systems. Understanding
T cell development is necessary to comprehend the development
of autoimmune diseases like cancer.
In
the thymus, the major histocompatability complex molecule
(MHC) acts as a “filter” for new T cells.
Although scientists have long known that the thymus
was the screening location for T cells, Dr. Staerz and
a team of researchers were able to identify the specific
peptide located on the MHC that positively selects T
cells. A peptide called ND1, located on MHC in the thymus,
was found to positively select T cells that later fight
disease in the body. It’s this peptide that the
T cell “sees” in the thymus.
The
thymus, a small organ located in the lower neck, helps facilitate
the normal development of the immune system early in life. The
thymus acts as a “filter” that selects T cells with
working receptors, which later sample peptides on the surface
of cells. Most of the T cells that don’t have the correct
receptors and can potentially attack the immune system are screened
by the thymus and then destroy themselves. However, some T cells,
which later may cause an autoimmune disease, pass throught the
thymus because not all antigens that can be seen by T cells are
present in this organ.
A
positively selected T cell is allowed to pass through the thymus
because it contains receptors that can identify peptides and mount
an immune system response, if appropriate. T cells that attack
foreign entities in the immune system roam the body looking for
these peptides.
Peptides
contain information about cell health and are often the first
notice the immune system receives about a disease attacking the
body. Peptides are brought to the surface of the cell by MHC molecules
that continually sample a cell for disease.
National
Jewish Medical and Research Center is the number one hospital
in the United States for respiratory disease treatment, U.S. News
& World Report, 1998-2000.
This
article has been adapted from a news release on what T cells “see”
in a normal thymus that controls the development of immune-system
aggressive T cells that was issued by National Jewish Medical
And Research Center, www.nationaljewish.org.
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