Scientists Isolate Immune
System Master 'On-Off Switch'
By Jonathan Birt
LONDON (Reuters) - Scientists have isolated a gene which they believe acts as an on/off switch for the body's immune system, promising new ways of treating conditions ranging from cancer to Crohn's Disease, the British company behind the breakthrough said on Tuesday. Researchers at the U.S. arm of Chiroscience Group Plc are also close to locating a second gene which could reverse bone wasting caused by osteoporosis, a condition which affects millions of people over 60 and leads to more than one million fractures in the U.S. every year. Research and Development Director Robert Jackson said uncovering the gene which regulates the body's immune response could one day lead to development of a whole new range of drugs. ``Sometimes you want to turn it off and sometimes you want to turn it on,'' Jackson told Reuters. Turning the immune sytem on or up could help in conditions like AIDS and cancer, where the body's efforts to fight off tumours are currently too weak. ``If we could strengthen that, we could develop drugs to help the body react to tumours,'' Jackson said. But switching it off or down might be useful in a range of diseases caused by an overly fierce immune response -- such as rheumatoid arthritis, diabetes, psoriasis, Crohn's Disease, ulcerative colitis and allergy. Gene-based research at the former Darwin Molecular business in Seattle, Washington, which Chiroscience bought in 1996, is also close to locating a mutant gene which may offer a way of reversing the effects of osteoporosis for the first time. Scientists are studying around 100 people and their families in South Africa with extremely strong bones caused by a mutant gene which causes bone density to increase as people age -- the exact opposite of osteoporosis. ``We are close to identifying a unique bone structure gene for osteoporosis,'' Chief Executive Officer John Padfield told Reuters. ``All other treatments try to stop bone loss getting worse. What our gene appears to do is increase bone density very substantially -- if this turns out to be true when we test a drug, that would be a revolutionary treatment for osteoporosis.'' The company announced the discoveries as part of a day-long update on its research and development activities. Shares in Chiroscience were up seven percent or 17 1/2 pence in early afternoon trading in London. Chiroscience said it will also work with the small British genome company Gemini Research, which has built up a database of genetic information based on identical twins. The two companies are to look for mutant genes linked to obesity.