Institute of Clinical Chemistry, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20251 Hamburg, Germany.
Eur J Cell Biol. 2010 Jan;89(1):87-94. doi: 10.1016/j.ejcb.2009.11.018.
Members of the family of carcinoembryonic antigen (CEA)-related cell adhesion molecules (CEACAMs) belonging to the immunoglobulin (Ig) superfamily are expressed in a variety of normal and malignant human tissues. As components of the cell membrane, these glycoproteins can make contact with adjacent cells. CEACAM1 and CEACAM5 (CEA) express Lewis(x) (Le(x)) structures. As shown by mass spectrometry in conjunction with enzymatic digestion, CEACAM1 contains at least seven Le(x) residues. Fucosyltransferase IX is the main fucosyltransferase responsible for attachment of terminal fucose, the key feature of the Le(x) structure, to CEA and CEACAM1. The Le(x) residues of both, CEACAM1 and CEA, interact with the human Le(x)-binding glycan receptors DC-SIGN and SRCL. Since subpopulations of human macrophages express DC-SIGN or SRCL, Le(x)-carrying CEACAMs may modulate the immune response in normal tissues such as the human placenta or in malignant tumours, for example in colorectal, pancreatic or lung carcinomas.
癌胚抗原（CEA）相关细胞黏附分子（CEACAMs）家族成员属于免疫球蛋白（Ig）超家族，在多种正常和恶性人类组织中表达。作为细胞膜的组成部分，这些糖蛋白可以与相邻细胞接触。CEACAM1 和 CEACAM5（CEA）表达 Lewis(x)（Le(x)）结构。如质谱分析与酶消化相结合所示，CEACAM1 至少含有七个 Le(x)残基。岩藻糖基转移酶 IX 是负责将末端岩藻糖附着到 CEA 和 CEACAM1 上的主要岩藻糖基转移酶，Le(x)结构的关键特征。CEACAM1 和 CEA 的 Le(x)残基都与人类 Le(x)结合聚糖受体 DC-SIGN 和 SRCL 相互作用。由于人类巨噬细胞的亚群表达 DC-SIGN 或 SRCL，因此携带 Le(x)的 CEACAMs 可能调节正常组织（如人胎盘）或恶性肿瘤（如结直肠癌、胰腺癌或肺癌）中的免疫反应。
