Polarized expression of CD74 by gastric epithelial cells
Polarized expression of CD74 by gastric epithelial cells
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DOI：
10.1369/jhc.4a6552.2005
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发表时间：
2005-12-01
影响因子：
3.2
通讯作者：
Reyes, VE
中科院分区：
文献类型：
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作者：
Barrera, CA;Beswick, EJ;Reyes, VE
CD74 被称为主要组织相容性复合体 (MHC) II 类相关的不变链 (Ii)，可调节 MHC II 类分子的细胞生物学和功能。 II类MHC和Ii表达被认为仅限于经典抗原呈递细胞(APC)，然而，在炎症期间，其他细胞类型，包括粘膜上皮细胞，也被报道表达II类MHC分子。鉴于 Ii 在 II 类 MHC 生物学中的重要性，我们试图检测胃上皮细胞 (GEC) 的 Ii 表达，以确定这些非常规 APC 细胞中的 II 类 MHC 分子是否受到 Ii 的控制，并进一步支持这些细胞在幽门螺杆菌感染期间的局部免疫和炎症反应中可能发挥的作用。因此，我们检查了来自人类活检样本的 GEC 上的 Ii 表达，然后使用独立方法在几个 GEC 系上证实了这一观察结果。通过 RT-PCR 检测了 Ii 的 mRNA，还检测了各种蛋白质亚型。有趣的是，这些细胞具有高水平的表面 Ii 表达，其极化至顶端表面。这些研究首次证明了人类 G 的 Ii 组成型表达
CD74 is known as the major histocompatibility complex (MHC) class II-associated invariant chain (Ii) that regulates the cell biology and functions of MHC class II molecules. Class II MHC and Ii expression was believed to be restricted to classical antigen-presenting cells (APC) however, during inflammation, other cell types, including mucosal epithelial cells, have also been reported to express class II MHC molecules. Given the importance of Ii in the biology of class II MHC, we sought to examine the expression of Ii by gastric epithelial cells (GEC) to determine whether class II MHC molecules in these nonconventional APC cells were under the control of Ii and to further support the role that these cells may play in local immune and inflammatory responses during Helicobacter pylori infection. Thus we examined the expression of Ii on GEC from human biopsy samples and then confirmed this observation using independent methods on several GEC lines. The mRNA for Ii was detected by RT-PCR, and the various protein isoforms were also detected. Interestingly, these cells have a high level expression of surface Ii, which is polarized to the apical surface. These studies are the first to demonstrate the constitutive expression of Ii by human G