Autoimmune diseases such as multiple sclerosis ensue when a patient's immune system begins attacking their own body tissues. Although most people have potentially autoreactive immune cells in their body, autoimmunity is normally prevented. How this is achieved is not readily apparent, but it could be because of a population of CD8 suppressor cells. In the May issue of Nature Immunology, scientists have now definitely proven the existence of these cells.
Harvey Cantor and colleagues generated mice deficient in the protein Qa-1. These mice had exaggerated immune responses when re-exposed to either foreign or self tissue to which they had been previously exposed. Enhanced responses to their own tissues were associated with increased susceptibility to experimental autoimmune encephalitis, the murine form of multiple sclerosis. The authors determined that activated suppressor CD8 T cells (which require Qa-1 for their generation) were missing and that this was critical for the development of autoimmune disease. In normal circumstances, these suppressor T cells prevent autoreactive cells from dividing and thereby prevent autoimmunity. How they inhibit the cells from proliferating, however, is still not known.
Dr. Harvey Cantor
Harvard Medical School, Dana-Farber Cancer Institute
Tel: +1 617 632 3348
Dr. Leonard Chess
New York, NY
Tel: +1 212 305 9986
Also available online.
(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza