Blue M L, Levine H, Daley J F, Branton K R, Schlossman S F
Division of Tumor Immunology, Dana Farber Cancer Institute, Boston, MA.
J Immunol. 1989 Apr 15;142(8):2714-20.
The acquisition of surface class I MHC molecules is associated with the maturation of thymocytes. Here, surface expression of class I MHC and CD1, which represents a family of MHC-related molecules, was analyzed on various human immature and mature thymocyte subpopulations. Class I expression was inversely related to the expression of CD1. The majority of CD4+ CD8+ cortical type thymocytes expressed low levels of class I MHC Ag, the previously described CD4+ CD8+ thymocyte subpopulation with low CD8 expression exhibited intermediate levels of class I MHC, whereas most of the single positive CD4 and CD8 thymocytes displayed high levels of class I MHC. Biochemical comparison of CD1 and class I showed that thymic class I molecules were post-translationally modified by phosphorylation, whereas CD1 was not phosphorylated. Furthermore, our studies suggested that in addition to CD1/CD8 complexes, thymocytes bear CD8/class I complexes. Chemical cross-linking and peptide mapping studies clearly identified the CD8-associated protein on thymic clones as the class I MHC molecule.
表面I类主要组织相容性复合体（MHC）分子的获得与胸腺细胞的成熟相关。在此，我们分析了I类MHC和CD1（代表一类与MHC相关的分子家族）在各种人类未成熟和成熟胸腺细胞亚群上的表面表达情况。I类分子的表达与CD1的表达呈负相关。大多数CD4+CD8+皮质型胸腺细胞表达低水平的I类MHC抗原，先前描述的具有低CD8表达的CD4+CD8+胸腺细胞亚群表现出中等水平的I类MHC，而大多数单阳性CD4和CD8胸腺细胞则显示出高水平的I类MHC。CD1和I类分子的生化比较表明，胸腺I类分子在翻译后通过磷酸化进行修饰，而CD1未被磷酸化。此外，我们的研究表明，除了CD1/CD8复合物外，胸腺细胞还带有CD8/I类复合物。化学交联和肽图谱研究明确鉴定出胸腺克隆上与CD8相关的蛋白为I类MHC分子。
