But in many cases autoimmune disease may involve abnormal responses by T regulatory cells, the UCSF researchers said. In recent years immunologists have come to recognize the important role that T regulatory cells normally play not only in ramping down an immune response during recovery from infection, but also in preventing autoimmune responses.
"Instead of an immune response that attacks, it's an immune response that suppresses attack," Rosenblum said. The two types of cells exist in a balance, and the balance is disrupted in autoimmune disease.
The UCSF researchers wanted to explore how autoimmunity may become self-limiting or wane over time. Physicians have observed that in many cases an autoimmune disease that attacks a single organ is worst when it first arises, with later flare-ups becoming less severe.
Similarly, Abbas, Rosenblum and Gratz were curious about the success of desensitization "allergy shots" for some allergy patients. Like our own self proteins, allergens such as certain pollens pose no disease threat. But in people with allergies the immune system goes on the attack anyway.
However, with repeated injections, with gradually increased doses of the same allergen, even evil ragweed-induced sneezing, itching and stuffiness can be relieved.
The UCSF scientists genetically engineered a strain of mice in which they could switch on or off the production of a particular self protein, called ovalbumin, in the skin. The mice were triggered to make an overabundance of the protein, which provoked an autoimmune response.
However, the presence of the protein also stimulated the activation of T regulatory cells. The activated T regulatory cells proliferated and transformed into a more potent form that better suppresses autoimmunity.
When the researchers again boosted ovalbumi
|Contact: Jeffrey Norris|
University of California - San Francisco