Viville S, Neefjes J, Lotteau V, Dierich A, Lemeur M, Ploegh H, Benoist C, Mathis D
Laboratorie de Génétique Moléculaire des Eucaryotes du CNRS, Strasbourg, France.
Cell. 1993 Feb 26;72(4):635-48. doi: 10.1016/0092-8674(93)90081-z.
The invariant chain (li) has aroused much interest because of its close association with major histocompatibility complex (MHC) class II molecules. Various functions have been proposed for it; several of these have received experimental support, but most have not been definitively proven, owing largely to uncertainties inherent in the experimental systems employed. We have now generated a line of mice devoid of the invariant chain by introducing a drastic mutation into the li gene. Cells from mutant animals show aberrant transport of MHC class II molecules, resulting in reduced levels of class II complexes at the surface, and these do not have the typical compact conformation indicative of tight peptide binding. Consequently, mutant cells present protein antigens very poorly and mutant mice are deficient in producing and at negatively selecting CD4+ T cells.
恒定链（Ii）因其与主要组织相容性复合体（MHC）II类分子的紧密关联而备受关注。人们对其提出了多种功能；其中一些已得到实验支持，但大多数尚未得到确凿证实，这主要是由于所用实验系统存在固有的不确定性。我们现在通过在Ii基因中引入一个剧烈突变，培育出了一条缺乏恒定链的小鼠品系。突变动物的细胞显示出MHC II类分子的异常转运，导致表面II类复合体水平降低，且这些复合体不具有表明紧密肽结合的典型紧密构象。因此，突变细胞呈递蛋白质抗原的能力非常差，突变小鼠在产生和阴性选择CD4 + T细胞方面存在缺陷。
