The immune system somehow manages to turn itself off after fighting an infection. Research by David S. Strayer of the University of Texas in Houston indicates that viruses use the same "off" mechanism to dodge the immune system, and that the immune system in turn can eventually counter the ploy.
Strayer's work, presented at the Sixth International Congress of Immunology earlier this month in Toronto, fits into an idea gaining a foothold in immunology -- that the immune system actively inhibits its own suppressive response, turning itself back on after it has turned itself off. The process is known as contrasuppression. Proponents of the theory believe overambitious contrasuppression causes the immune system to attack itself in autoimmune diseases.
Strayer infected rabbits with a virus and looked at their immune-cell-harboring spleens. In the test tube, spleen cells collected 7 days after infection were capable of only a low response to immune stimulators, but spleen cells collected 11 days after infection were better able to respond. The liquid portion of the 7-day cell culture, but not from the 11-day cells, contained a substance that suppressed other immune cells.
The virus, Strayer suggests, activates the natural suppression of the immune system, causing the 7-day cells to produce and secrete a substnace that suppresses the immune response. By day 11, the rabbits' immune systems were suppressing the virus-induced suppression.
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|Title Annotation:||immune system research|
|Date:||Aug 2, 1986|
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