Sanders S K, Giblin P A, Kavathas P
Department of Laboratory Medicine, Immunobiology, and Human Genetics, Yale University School of Medicine, New Haven, Connecticut 06510.
J Exp Med. 1991 Sep 1;174(3):737-40. doi: 10.1084/jem.174.3.737.
The lymphocyte differentiation marker CD8 acts as a coreceptor with the T cell receptor (TCR) during recognition of peptide presented by major histocompatibility complex (MHC) class I molecules. The functions of CD8 in the TCR complex are thought to be signaling through the association of CD8 with the protein tyrosine kinase p56lck and adhesion to MHC class I through the alpha 3 domain. While the ability of the CD8 alpha/alpha homodimer to bind to classical MHC class I molecules has been shown, it is unclear whether CD8 can also bind nonclassical molecules. Of particular interest is human histocompatibility leukocyte antigen (HLA)-G which is expressed on placental cytotrophoblast cells. These cells do not express HLA-A, -B and -C molecules. In this report, we demonstrate that CD8 can bind to HLA-G. It is possible, therefore, that a cell bearing CD8 may interact with HLA-G-expressing cells.
淋巴细胞分化标志物CD8在识别由主要组织相容性复合体（MHC）I类分子呈递的肽段过程中，作为T细胞受体（TCR）的共受体发挥作用。CD8在TCR复合物中的功能被认为是通过CD8与蛋白酪氨酸激酶p56lck的结合进行信号传导，并通过α3结构域与MHC I类分子发生黏附。虽然已证明CD8α/α同二聚体能够结合经典的MHC I类分子，但尚不清楚CD8是否也能结合非经典分子。特别值得关注的是在胎盘细胞滋养层细胞上表达的人类组织相容性白细胞抗原（HLA）-G。这些细胞不表达HLA-A、-B和-C分子。在本报告中，我们证明CD8能够结合HLA-G。因此，携带CD8的细胞有可能与表达HLA-G的细胞发生相互作用。
