van den Berg T K, Nath D, Ziltener H J, Vestweber D, Fukuda M, van Die I, Crocker P R
Department of Cell Biology and Immunology, Institute for Immunology and Inflammation, Faculty of Medicine, Vrije University, Amsterdam, The Netherlands.
J Immunol. 2001 Mar 15;166(6):3637-40. doi: 10.4049/jimmunol.166.6.3637.
Sialoadhesin (Siglec-1) is a macrophage-restricted sialic acid-binding receptor that mediates interactions with hemopoietic cells, including lymphocytes. In this study, we identify sialoadhesin counterreceptors on T lymphocytes. Several major glycoproteins (85, 130, 240 kDa) were precipitated by sialoadhesin-Fc fusion proteins from a murine T cell line (TK-1). Binding of sialoadhesin to these glycoproteins was sialic acid dependent and was abolished by mutation of a critical residue (R97A) of the sialic acid binding site in the membrane distal Ig-like domain of sialoadhesin. The 130- and 240-kDa sialoadhesin-binding glycoproteins were identified as the sialomucins CD43 and P-selectin glycoprotein ligand 1 (CD162), respectively. CD43 expressed in COS cells supported increased binding to immobilized sialoadhesin. Finally, sialoadhesin bound different glycoforms of CD43 expressed in Chinese hamster ovary cells, including unbranched (core 1) and branched (core 2) O:-linked glycans, that are normally found on CD43 in resting and activated T cells, respectively. These results identify CD43 as a T cell counterreceptor for sialoadhesin and suggest that in addition to its anti-adhesive role CD43 may promote cell-cell interactions.
唾液酸黏附素（Siglec-1）是一种巨噬细胞特异性的唾液酸结合受体，介导与包括淋巴细胞在内的造血细胞的相互作用。在本研究中，我们鉴定了T淋巴细胞上唾液酸黏附素的反受体。几种主要糖蛋白（85、130、240 kDa）可被唾液酸黏附素-Fc融合蛋白从小鼠T细胞系（TK-1）中沉淀出来。唾液酸黏附素与这些糖蛋白的结合依赖于唾液酸，并且通过唾液酸黏附素膜远端免疫球蛋白样结构域中唾液酸结合位点的关键残基（R97A）突变而被消除。130 kDa和240 kDa的唾液酸黏附素结合糖蛋白分别被鉴定为唾液黏蛋白CD43和P-选择素糖蛋白配体1（CD162）。在COS细胞中表达的CD43支持与固定化唾液酸黏附素的结合增加。最后，唾液酸黏附素结合了中国仓鼠卵巢细胞中表达的不同糖型的CD43，包括无分支（核心1）和分支（核心2）的O-连接聚糖，它们分别正常存在于静息和活化T细胞的CD上。这些结果将CD43鉴定为唾液酸黏附素的T细胞反受体，并表明除了其抗黏附作用外，CD43可能促进细胞间相互作用。 43上。这些结果将CD43鉴定为唾液酸黏附素的T细胞反受体，并表明除了其抗黏附作用外，CD43可能促进细胞间相互作用。
