Guest guest Posted April 28, 2000 Report Share Posted April 28, 2000 >Date: Fri, 28 Apr 2000 02:06:46 -0000 > >Thank you, . I missed the article. This has particular >relevance for GD patients since one of the triggers >associated with autoimune thyroid disease involves the PTEN >gene which regulates apoptosis. When it's missing, there is >increased apoptosis (programmed cell death). So the natural >killer (NK) cells which normally stop the autoreactive >process are wiped out before their time, leaving us >defenseless. A recent article in the Autoimmune and Related >Diseases Newsletter mentioned that his is where research is >heading. Hooray. > > WOW!. How interesting!. Here is another important one. Jack Spratt told me about it at 's board. I forwarded you a message from him. (Let me know if it reached you, since I used a board feature to do it. And it seems 'macs' have some problems to launch there. And maybe viceversa) What a pity he hasn't joined us so far... Keep well ************* How IL-2 And IL-15 Together Balance Immune System Each day, viruses attack the immune system looking to gain a foothold in the body and cause sickness. But the immune system regularly turns away these invaders by using antibodies and killer T cells that attack the antigen. Until now, scientists only knew that these events happened, but not how or why. A research team at National Jewish Medical and Research Center led by Philippa Marrack, Ph.D., and Kappler, Ph.D., report in today's issue of Science that they have discovered how certain proteins work together in the immune system to control the T cells that attack viruses such as chicken pox, measles and other diseases. National Jewish researchers have shown that the proteins IL-15 and IL-2 work together to balance the immune response against antigens. Researchers found that IL-15 drives the production and division of " memory " killer T cells and IL-2 kills these T cells as they divide. " Memory " T cells are the immune system's primary defenders against antigens. When the immune system first comes in contact with an antigen -- such as the viruses that cause chicken pox, measles or polio -- it creates killer T cells that then turn into " memory " T cells. If and when the antigen invades the immune system a second time, these " memory " T cells recognize the invader and bind to it, killing the antigen more quickly than during the first exposure. (This is why people don't get chicken pox, measles or similar immune diseases more than once.) " You get a nuclear holocaust, not just gunfire, " said Dr. Marrack, a National Jewish researcher who studies the inner workings of the immune system. Still, researchers were unsure if T cells maintained the ability to remember antigens from one exposure to another -- there could be decades between exposures -- by lying in wait, by being exposed to antigens regularly, or by holding on to small parts of the virus. Recently, National Jewish researchers found that none of these explanations were quite right. Rather, " memory " T cells stay alive for many years because they divide slowly, stimulated by a special hormone (cytokine) of the immune system, IL-15. Another immune system cytokine, IL-2, prevents this IL-15-induced production from getting out of control. Working together, IL-15 and IL-2 help to provide equilibrium to the immune system. When an immune response to an antigen is mounted, IL-15 is produced, which causes T cells to divide and attack the invader and stimulates " memory " T cells. At the same time that IL-15 production increases, IL-2 controls the proliferation of " memory " T cells -- caused by increasing amounts of IL-15 -- by killing some T cells as they divide. " In immune responses, " Dr. Marrack said, " the stimulatory effects of one cytokine are frequently counterbalanced by the inhibiting effects of another cytokine. This balance allows the immune system to battle antigens with a controlled response. " Interleukins are cytokines, proteins that are secreted by different types of cells in the body, and which regulate the intensity and length of immune responses. National Jewish scientists believe that this information could help doctors create better treatments in the future for immune diseases such as AIDS, lupus or rheumatoid arthritis. In the future, doctors may be able to use this knowledge to regulate the division of T cells. Changing the balance of the proteins that affect T cells -- in effect regulating the immune response to an antigen -- could be used successfully with medical therapies. " You might be able to attack that balance by changing either IL-2 or IL-15, " Dr. Marrack said. Chia Chi Ku, Ph.D., Masaaki Murakami, Ph.D., DVM, and Akemi Sakamoto, M.D., also contributed to this research. - By Jordan Gruener Related website: National Jewish Medical and Research Center Contact: Jordan Gruener] 28-Apr-2000 ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com Quote Link to comment Share on other sites More sharing options...
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