MR1 is an MHC class I-like molecule with unique structural and biological features that make it an important member among the molecules involved in antigen presentation to T cells. Distinctive features include ubiquitous expression of the MR1 gene and its monomorphism. Another relevant property is that the MR1 protein appears at very low levels on the plasma membrane and its surface expression is regulated by antigen binding. Finally, the nature of presented antigens differs from those that bind other presenting molecules and includes small metabolites of microbial and self-origin, small drugs and tumor-associated antigens. This opinion paper describes in detail some of those features and discusses recent literature in the field.

MR1是一种MHC I类分子，具有独特的结构和生物学特征，使其成为参与T细胞抗原呈递的分子中的重要成员。独特的特征包括MR1基因的普遍表达及其单态性。另一个相关特性是MR1蛋白在质膜上的含量非常低，并且其表面表达受抗原结合的调节。最后，呈递抗原的性质不同于结合其他呈递分子的性质，包括微生物和自身来源的小代谢物，小药物和与肿瘤相关的抗原。该意见书详细描述了其中一些功能，并讨论了该领域的最新文献。