Abstract：
Neural cell adhesion molecules (NCAMs) are large cell-surface glycoproteins playing important roles in cell-cell and cell-extracellular matrix interactions in nervous system. Recent study identified a homologue of NCAM (CgNCAM) from the Pacific oyster Crassostrea gigas. Its ORF was of 2634 bp which encodes a protein (877 amino acids) consisting of five immunoglobulin domains and two fibronectin type III domains. CgNCAM transcripts were broadly distributed in oyster tissues especially in mantle, labial palp and haemolymph. CgNCAM showed up-regulated expression in haemocytes of oysters after Vibrio splendidus and Staphylococcus aureus stimulation. The recombinant CgNCAM protein (rCgNCAM) was able to bind manose, lipopolysaccharide and glucan, as well as different microbes including Gram-negative bacteria and fungi. rCgNCAM displayed bacterial agglutination and hemagglutination activity. CgNCAM improved the phagocytosis of haemocytes towards V. splendidus by regulating the expression of CgIntegrin, CgRho J and CgMAPKK. Moreover, CgNCAM was involved in the extracellular trap establishment of haemocytes after V. splendidus stimulation. The results collectively indicated that CgNCAM acted as a recognition receptor executing multiple immune functions to recognize and eliminate invading microorganisms in innate immunity of oysters.
摘要：
神经细胞粘附分子（NCAM）是一种大型细胞表面糖蛋白，在神经系统的细胞-细胞和细胞-细胞外基质相互作用中起重要作用。最近的研究确定了太平洋牡蛎Crassostreagigas的NCAM（CgNCAM）同源物。其ORF为2634bp,其编码由五个免疫球蛋白结构域和两个纤连蛋白III型结构域组成的蛋白质(877个氨基酸)。CgNCAM转录本广泛分布在牡蛎组织中，尤其是地幔中，唇触诊和血淋巴。脾弧菌和金黄色葡萄球菌刺激后，CgNCAM在牡蛎血细胞中表达上调。重组CgNCAM蛋白（rCgNCAM）能够结合甘露糖，脂多糖和葡聚糖，以及不同的微生物，包括革兰氏阴性细菌和真菌。rCgNCAM显示细菌凝集和血凝活性。CgNCAM通过调节Cg整合素的表达改善血细胞对脾弧菌的吞噬作用，CgRhoJ和CgMAPKK。此外，CgNCAM参与脾弧菌刺激后血细胞的细胞外陷阱建立。结果共同表明，CgNCAM充当识别受体，执行多种免疫功能，以识别和消除牡蛎先天免疫中的入侵微生物。
