Hanau D, Fabre M, Schmitt D A, Garaud J C, Pauly G, Tongio M M, Mayer S, Cazenave J P
Proc Natl Acad Sci U S A. 1987 May;84(9):2901-5. doi: 10.1073/pnas.84.9.2901.
HLA-DR and T6 surface antigens are expressed only by Langerhans cells and indeterminate cells in normal human epidermis. We have previously demonstrated that T6 antigens are internalized in Langerhans cells and indeterminate cells by receptor-mediated endocytosis. This process is induced by the binding of BL6, a monoclonal antibody directed against T6 antigens. In the present study, using a monoclonal antibody directed against HLA-DR antigens, on human epidermal cells in suspension, we show that the surface HLA-DR antigens are also internalized by receptor-mediated endocytosis in Langerhans and indeterminate cells. Moreover, using immunogold double labeling, we demonstrate that T6 and HLA-DR antigens are internalized through common coated regions of the membrane of Langerhans or indeterminate cells. The receptor-mediated endocytosis that is induced involves coated pits and vesicles, receptosomes, lysosomes, and also, in Langerhans cells, the Birbeck granules. Thus, T6 antigens, which are considered to be "unusual" or "nonclassical" major histocompatibility complex class I molecules, and the major histocompatibility complex class II molecules, HLA-DR, are internalized in Langerhans and indeterminate cells through common receptor-mediated endocytosis organelles.
HLA - DR和T6表面抗原仅在正常人表皮的朗格汉斯细胞和未定型细胞中表达。我们之前已经证明，T6抗原通过受体介导的内吞作用在朗格汉斯细胞和未定型细胞中内化。这个过程是由针对T6抗原的单克隆抗体BL6的结合所诱导的。在本研究中，我们使用针对HLA - DR抗原的单克隆抗体，对悬浮的人表皮细胞进行研究，结果表明，表面HLA - DR抗原同样通过受体介导的内吞作用在朗格汉斯细胞和未定型细胞中内化。此外，通过免疫金双重标记，我们证明T6和HLA - DR抗原通过朗格汉斯细胞或未定型细胞膜的共同被膜区域内化。所诱导的受体介导的内吞作用涉及被膜小窝和小泡、内吞体、溶酶体，并且在朗格汉斯细胞中还涉及伯贝克颗粒。因此，被认为是“异常”或“非经典”的主要组织相容性复合体I类分子的T6抗原，以及主要组织相容性复合体II类分子HLA - DR，通过共同的受体介导的内吞细胞器在朗格汉斯细胞和未定型细胞中内化。
