Streilein J W
Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114, USA.
Transplant Proc. 1996 Aug;28(4):2066-70.
Immune privilege is finally emerging from the curiosity shop into the mainstream of immunology. Immune privileged tissues and sites play a critical role in creating the privileged status, in part by creating peripheral tolerance among antigen-specific T and B cells. While the old idea of "antigen sequestration behind blood: tissue barriers and at sites without efferent lymphatics" seems effete, it appears that a novel view of antigen sequestration is emerging that requires that both immunologic ignorance and peripheral tolerance be considered as relevant to the privileged state. We have argued that immune privilege is an evolutionary adaptation that enables "vulnerable" tissues to arrange for immune protection without suffering the consequences of immunopathogenic damage. In the case of the eye (our organ of interest), privilege enables the eye to avoid immunogenic inflammation. For this specialized organ of sense, inflammation is an unavoidable cause of blindness because inflammation disrupts microanatomic arrangements, and maintenance of the microanatomy of the visual axis is essential for sight. Because immune privilege requires active participation of the immune system for its induction and its maintenance, and since this participation involves the systemic immune apparatus, the tolerance achieved by antigens placed in privileged sites is actually systemic. Therefore, the strategies that are used by privileged sites and tissues to create tolerance parochially, may actually have relevance for creating tolerance of antigenic materials placed at nonprivileged sites of the body.
免疫赦免终于从稀奇事物变成了免疫学的主流。免疫赦免组织和部位在建立赦免状态中发挥着关键作用，部分原因是通过在外周抗原特异性T细胞和B细胞中建立外周耐受。虽然“血液屏障和无输出淋巴管部位背后的抗原隔离”这一旧观念似乎已过时，但一种新的抗原隔离观点正在出现，这种观点认为免疫忽视和外周耐受都与赦免状态相关。我们认为免疫赦免是一种进化适应，它使“脆弱”组织能够在不遭受免疫致病损伤后果的情况下获得免疫保护。就眼睛（我们感兴趣的器官）而言，赦免使眼睛能够避免免疫原性炎症。对于这个特殊的感觉器官来说，炎症是导致失明的一个不可避免的原因，因为炎症会破坏微观解剖结构，而视觉轴微观解剖结构的维持对视力至关重要。由于免疫赦免需要免疫系统的积极参与来诱导和维持，而且这种参与涉及全身免疫系统，因此置于赦免部位的抗原所实现的耐受实际上是全身性的。所以，赦免部位和组织局部建立耐受所采用的策略，实际上可能与在身体非赦免部位建立抗原物质的耐受有关。
