Cytokine Identified that Reduces Autoimmune Response

Researchers studying the biochemical triggers that activate the immune response have found that the IL-27 cytokine may actually suppress CD4 T cells, the helper T-cells that coordinate the immune system response to infections.

Investigators at the University of Pennsylvania (Philadelphia, USA) genetically engineered a line of mice lacking the IL-27 receptor protein WSX-1. These animals were infected with the intracellular pathogen Toxoplasma gondii. Results of the study published in the November 2003 issue of Immunity showed that the mice established protective T-cell responses, characterized by production of inflammatory cytokines and control of parasite replication.

However, infected mice lacking WSX-1 were unable to down regulate these protective responses and developed a lethal, T-cell-mediated inflammatory disease. The autoimmune pathology was characterized by the excessive production of gamma interferon, persistence of highly activated T-cells, and enhanced T-cell proliferation.

"There are many immune-mediated diseases with many different causes, but this particular pathway may represent a universal checkpoint for the immune system,” explained senior author Dr. Christopher Hunter, associate professor of pathobiology at the University of Pennsylvania. "It may be possible to create drugs that turn the immune system off without actually suppressing the beneficial immune reactions.”




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