Gebicke-Haerter P J, Van Calker D, Nörenberg W, Illes P
Department of Psychiatry, University of Freiburg, Germany.
Neurochem Int. 1996 Jul;29(1):1-12.
Microglia are the resident immunocompetent cells of the brain, comparable to other tissue macrophages, e.g. Kupffer cells in the liver or Langerhans cells in the skin. In disease, however, the central nervous system appears to be a largely immunosuppressive environment, which previously led to the hypothesis that it is an "immunologically privileged" organ. Nevertheless, microglia can be activated by various internal and external stimuli, resulting in expression of cytokines and other mediators of inflammation. The molecular mechanisms converting those signals into specific microglial responses are a field of intensive research efforts. These have been performed both on cultured microglia and in vivo. Although the situation in vivo is sometimes difficult to interpret, considerable progress on the molecular level has been made using a number of excellent animal model systems combined with advanced detection techniques. Moreover, isolation and culture of microglia is becoming a standard method in an increasing number of laboratories, which allows a closer look at their reactions towards a variety of test substances. Both aspects have been covered in this paper. It turns out that microglia are extremely sensitive towards any kind of stimulus. They are probably the first cells in the brain "sensing" changes in the periphery, and the summarized data suggest that microglia may even react in a specific manner in response to a specific stimulus. Under the notion that not only multiple sclerosis, but also further chronic degenerative diseases of the brain, are based on a common autoimmune mechanism, better insights into microglial activation and its prolonged maintenance are of outstanding scientific interest.
小胶质细胞是脑内固有的具有免疫活性的细胞，与其他组织中的巨噬细胞类似，例如肝脏中的库普弗细胞或皮肤中的朗格汉斯细胞。然而，在疾病状态下，中枢神经系统似乎是一个很大程度上具有免疫抑制作用的环境，这一点以前导致了它是一个“免疫特权”器官的假说。尽管如此，小胶质细胞可被各种内部和外部刺激激活，从而导致细胞因子和其他炎症介质的表达。将这些信号转化为特定小胶质细胞反应的分子机制是一个深入研究的领域。这方面的研究工作既有在培养的小胶质细胞上进行的，也有在体内进行的。虽然体内的情况有时难以解释，但利用一些出色的动物模型系统结合先进的检测技术，在分子水平上已经取得了相当大的进展。此外，小胶质细胞的分离和培养在越来越多的实验室中正在成为一种标准方法，这使得能够更仔细地观察它们对各种测试物质的反应。本文涵盖了这两个方面。结果表明，小胶质细胞对任何一种刺激都极其敏感。它们可能是脑内“感知”外周变化的首批细胞，汇总的数据表明小胶质细胞甚至可能以特定方式对特定刺激作出反应。基于不仅多发性硬化症，而且脑的其他慢性退行性疾病都基于共同的自身免疫机制这一观点，深入了解小胶质细胞的激活及其长期维持具有突出的科学意义。
