The function of invariant chain in class II-restricted antigen presentation.
The function of invariant chain in class II-restricted antigen presentation.
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DOI：
10.1006/smim.1995.0042
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发表时间：
1995-12-01
影响因子：
7.8
通讯作者：
Sant, A J
中科院分区：
文献类型：
--
作者：
Ceman, S;Sant, A J
不变链（Ii）在抗原呈递中的作用已经用两种独立的方法进行了研究。首先是用II类分子和各种形式的II类分子重建细胞系；第二种是产生缺乏Ii基因功能表达的小鼠（Ii.）。这两种类型的研究都表明，Ii促进了Ii类分子在内质网（ER）中的组装，通过内体隔室陪伴或保留适当折叠的Ii类复合物，最终作为t细胞配体。Ii如何促进Ii类抗原肽复合物的组装尚不清楚，似乎取决于以下几个因素：研究的抗原和表位；注射途径：注射抗原的途径和剂量；现在的形式；以及实验中使用的应答T细胞。在Ii类肽复合物的组装过程中，Ii可以通过多种方式促进这一过程：具体地说，通过增加内体囊泡中Ii类可用的量；改变II类分子在内体途径中的进入或保留；在CLIP解离过程中促进肽交换，或者最后通过调节细胞中的抗原加工环境。综上所述，我们提出Ii类肽复合物在组装过程中不仅仅扮演一个角色，Ii可能执行上述所有的活性，在抗原递呈途径中以不同的能力发挥作用。
The role of invariant chain (Ii) in antigen presentation has been studied using two independent approaches. The first was to reconstitute cell lines with class II molecules and various forms of the Ii; the second has been to generate mice that lack functional expression of the Ii gene (Ii.). Both types of studies show that Ii facilitates assembly of class II molecules in the endoplasmic reticulum (ER), chaperones or retains properly folded class II complexes through endosomal compartments, and finally, serves as a T-cell ligand. How Ii facilitates assembly of antigenic class II-peptide complexes is less clear and seems to depend on a number of factors reviewed here: the antigen and epitope studied; the route and dose by which antigen is administered; the form of Ii present; and the responding T cell used in the experiment. During assembly of the class II-peptide complex, Ii may facilitate this process in a number of ways: specifically, by increasing the amount of class II available in endosomal vesicles; changing access or retention of class II molecules in the endosomal pathway; facilitating peptide exchange during CLIP dissociation, or finally, by modulating the antigen processing environment in the cell. In summary, we propose that instead of playing just one role in assembling the class II-peptide complex, Ii may perform all of the above described activities, functioning in different capacities along the pathway of antigen presentation.