ST. LOUIS, Mo., July 24, 1998 -- A report in today's issue of Science helps answer a question that has had scientists scratching their heads: How do immune cells tailor their responses to invading microbes while ignoring the body's own cells?
The part of the cell that detects harmful organisms has to punch in a code before the cell will go on the offensive, the researchers have found. Punching in just part of the code is as useless as entering the wrong security code into a lock.
"People have been trying to identify the steps that occur in the resting cell and during activation, but previous methods failed to reveal this, so no one could make heads or tails of it," says lead researcher Paul M. Allen, Ph.D., the Robert L. Kroc Professor of Pathology at Washington University School of Medicine in St. Louis. "We tried a different approach, and an elegant solution to this question emerged."
One of Allen's graduate students, Ellen Neumeister Kersh, is the paper's lead author. Andrey S. Shaw, M.D., associate professor of pathology, also took part in the study, which was funded by the National Institutes of Health.
The researchers studied helper T cells, a key component of the cellular immune system. When the supply of these cells dwindles, as in AIDS patients, the consequences are dire.
Helper T cells patrol the body, checking for harmful microbes. Other parts of the immune system blow an invader's cover by posting fragments of its proteins on its surface or on the surface of a cell where it's hiding out. Helper cells read these fragments -- called antigens -- like cops checking out a license plate. If the plate is foreign, they make the appropriate response. They may kill the microbe directly, help a killer T-cell dispose of a virus-infected cell or stimulate immune cells that manufacture antibodies.
Helper cells use receptors on their surface to read antigenic displays.
But instead of getting close
Contact: Linda Sage
Washington University School of Medicine