An immunotherapy approach is turned to treating autoimmune conditions: scientists have "turned the tables on an autoimmune disease. In such diseases, including Crohn's and rheumatoid arthritis, the immune system mistakenly attacks the body's tissues. But the scientists managed to trick the immune systems of mice into targeting one of the body's players in autoimmune processes, an enzyme known as MMP9. ... [Researchers] have spent years looking for ways to home in on and block members of the matrix metalloproteinase (MMP) enzyme family. These proteins cut through such support materials in our bodies as collagen, which makes them crucial for cellular mobilization, proliferation and wound healing, among other things. But when some members of the family, especially MMP9, get out of control, they can aid and abet autoimmune disease and cancer metastasis. Blocking these proteins might lead to effective treatments for a number of diseases. ... rather than attempting to design a synthetic molecule to directly attack MMPs [an] MMP immunization would trick the body into creating antibodies that block the enzyme at its active site. [Researchers] created an artificial version of the metal zinc-histidine complex at the heart of the MMP9 active site. They then injected these small, synthetic molecules into mice and afterward checked the mice's blood for signs of immune activity against the MMPs. ... when they had induced an inflammatory condition that mimics Crohn's disease in mice, the symptoms were prevented when mice were treated with [the new synthetic molecules]. We are excited not only by the potential of this method to treat Crohn's, [but] by the potential of using this approach to explore novel treatments for many other diseases."