젊은 사람들이 나이든 사람들에 비해 인간광우병에 민감한 이유를 밝히려는 과학자들의 연구가 계속되고 있는 가운데… 로슬린 연구소의 과학자들은 쥐 실험을 통해 프리온 단백질과 면역계의 상호작용에 대한 연구결과를 발표했습니다.
변형 프리온은 중추신경계로 퍼지기 전에 비장, 림파구, 편도 등 면역계의 일부인 림프조직에 축적되는데, Neil Mabbott를 비롯한 로슬린 연구소의 학자들은 프리온은 필수불가결하게 면역계의 특별한 세포인 소포성 수지상 세포 (follicular dendritic cells)를 “납치(hijack)”하는 것을 확인했습니다.(변형 프리온 단백질이 소포성 수지상 세포와 반드시 결합하여 그 세포에서 축적되고 복제됩니다)
그러나 나이 든 쥐에서는 소포성 수지상 세포가 손상된(감소된) 것이 확인됐습니다.
광우병과 소포성 수지상 세포 (follicular dendritic cells)의 연관성은 예전에 [네이처]에도 발표된 바가 있습니다.
에든베러 대학의 로슬린 연구소 연구팀은 이번 연구결과가 인간광우병 예방백신 개발에 도움이될 것으로 판단하고 있다고 합니다.
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Cells link to CJD in young people | |||
출처 : BBC Page last updated at 15:49 GMT, Thursday, 15 October 2009 16:49 UK Patients diagnosed with variant CJD are just 28 years old on average. It has been unclear why older people have not been affected to the same extent. Now older cells, by working less efficiently than they used to due to age, are thought to hamper the disease. Edinburgh University scientists said it could help with vaccine development. The researches behind the study believe the findings could also improve the diagnosis of vCJD. Nervous system Analysing mice, researchers at the university’s Roslin Institute looked at how the immune system interacts with corrupted proteins, known as prions, which are linked to vCJD. Prions accumulate in lymphoid tissues, part of the body’s immune system which include the spleen, lymph nodes and tonsils, before spreading to the central nervous system, where they kill off brain cells and cause neurological disease. The researchers found that the prions essentially “hijack” specific cells in the immune system, known as follicular dendritic cells. The prions accumulate and replicate on the cells, until they reach a sufficient level to spread to the nerves and the brain.
But the study, funded by the Biotechnology and Biological Sciences Research Council, found that those cells were impaired in older mice. As a result, they were unable to trap and replicate the corrupted proteins and the mice did not develop clinical disease. Researchers said their study could explain why vCJD does not affect older humans to the same extent and why it occurs almost exclusively in young people. Dr Neil Mabbott, of The Roslin Institute, said: “It has always been unclear why younger people were more susceptible to variant CJD and the assumption that they were more likely to eat cheap meat products is far too simplistic. “Understanding what happens to these cells, which are important for the body’s immune responses, could help us develop better ways of diagnosing variant CJD or even find ways of preventing prions from spreading to the brain. It could also help to create a vaccine.” The findings are published in the Journal of Immunology. |