LAIR-1/LAIR-2(CD305/CD306)推定配体分布的研究

目的：研究LAIR-1（CD305）及LAIR-2（CD306）推定配体在多种细胞系上的分布，为鉴定LAIR-1／LAIR-2推定配体提供了实验依据。方法：建立稳定表达LAIR-1-Fc和LAIR-2-Fc融合蛋白的细胞系。以纯化的融合蛋白进行活细胞免疫荧光染色，用流式细胞仪检测LAIR-1及LAIR-2推定配体在多种细胞系膜表面的表达，并比较LAIR-1和LAIR-2推定配体的分布及可能结合的位点。结果：LAIR-1推定配体及LAIR-2推定配体均在人羊膜来源的上皮细胞系WISH上高表达，在人黑色素瘤细胞系C32、人胚肾上皮细胞系293T及人脐静脉内皮细胞系ECV304上有一定程度的表达。LAIR-1-Fc和LAIR-2-Fc融合蛋白与推定配体的结合，可分别被可同时识别LAIR-2和LAIR-1的单克隆抗体（mAb）FMU-LAIR-2．2和FMU-LAIR-2．1阻断。结论：LAIR-1推定配体及LAIR-2推定配体的分布基本一致，主要表达于WISH、C32、293T和ECV304细胞系。LAIR-1和LAIR-2可能拥有共同的配体。

Identification of cell lines expressing the putative ligand(s) for LAIR-1(CD305) and LAIR-2(CD306)

AIM: To identify cell lines expressing the putative ligand(s) for LAIR-1 and LAIR-2. METHODS: CHO cell lines secreting LAIR-1-Fc or LAIR-2-Fc fusion protein were prepared and the supernatants from the CHO cell lines were collected and purified by protein A affinity chromatography column. Several cell lines were stained with the purified LAIR-1-Fc and LAIR-2-Fc fusion proteins and then analyzed by flow cytometry for detecting the expression of their putative ligand(s). To exclude non-specific binding between the cells and the fusion proteins, the cell lines expressing their putative ligand(s) were pre-incubated with the mAbs against LAIR-1 or LAIR-2, stained with the fusion proteins, and analyzed by flow cytometry. RESULTS: Both LAIR-1 and LAIR-2 fusion proteins bound strongly with human amnion-derived epithelial cell line WISH, and moderately with human melanoma cell line C32, human embryo kidney epithelial cell line 293T, and human umbilical vein endothelial cell line ECV304. Furthermore, this binding could be blocked by the mAb FMU-LAIR-2.2 (recognizing both LAIR-1 and LAIR-2) or mAb FMU-LAIR-2.1(recognizing LAIR-2). CONCLUSION: The putative ligand(s) for LAIR-1 and LAIR-2 were expressed on WISH, C32, 293T and ECV304 cell lines. LAIR-1and LAIR-2 may share the same ligand(s). These findings lay the foundation for the molecular cloning of the putative ligand(s) for LAIR-1and LAIR-2.