Thymus-independent development of gut T cells.
Thymus-independent development of gut T cells.
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肠道 T 细胞的胸腺独立发育。
DOI：
10.1159/000058720
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Klein,JR
中科院分区：
文献类型：
--
作者：
Klein,JR
从免疫学的角度来看，肠道上皮被赋予了一项看似不可能完成的任务--一方面它必须防止潜在有害病原体和抗原的进入和传播，但同时它又不能干扰对有机体生存至关重要的营养源的吸收。因此，也许并不奇怪，肠道上皮中的T细胞，即上皮内淋巴细胞(IEL)，具有许多使它们与动物其他部位的T细胞不同的特征，或者是局部“入境口岸”的免疫机制不同于那些旨在控制体内抗原传播的机制。同样，在这种情况下，也可以证明肠道和胸腺的胸腺生成潜力之间存在基于进化的关系。因此，例如，有组织的淋巴组织首先以肠道相关淋巴组织(GALT)的形式在无脊椎动物(如七鳃鳗)中变得明显，然后在演化中出现胸腺和脾在颌口[1]。奇怪的是，在脊椎动物的进化中，直到GALT、胸腺和脾建立之后，骨髓才成为一种造血组织，这就引发了这样一个问题：骨髓的功能是否仅仅是协调淋巴细胞的发育，而以前在其他地方是独立发生的。无论如何，我们都可以假设胸腺起源于
From an immunological point of view, the intestinal epithelium is vested with a seemingly impossible task–it must on the one hand prevent the entry and dissemination of potentially harmful pathogens and antigens, yet it must simultaneously not interfere with the uptake of nutrient sources essential for survival of the organism. It is perhaps not surprising, therefore, that T cells in the gut epithelium, the intraepithelial lymphocytes (IELs), bear many characteristics which set them apart from T cells located elsewhere in the animal, or that mechanisms of immunity at a local ‘port of entry’such as the intestine differ from those designed to control the spread of antigen internally. In that vein, also, a case can be made for an evolutionarily-based relationship between the thymopoietic potential of the intestine and the thymus. Thus, for example, organized lymphoid tissues first become evident in Agnatha (eg lampreys) in the form of gut-associated lymphoid tissues (GALT), followed thereafter in evolution by appearance of the thymus and the spleen in the Gnathostoma [1]. Curiously, in the evolution of vertebrates the acquisition of bone marrow as a hematopoietic tissue does not occur until after the GALT, the thymus, and the spleen have become established, thus prompting the question of whether the function of the bone marrow may be merely to orchestrate the development of lymphocytes which previously had taken place independently elsewhere. Regardless, it is feasible to assume that the thymus arose as an adaptation of