从海蜇中获得一种新的糖蛋白JGP-III2，其糖含量为11.87%，蛋白含量为87.74%，分子量为39.5 kDa。JGP-III2中含有8种单糖分别为甘露糖、2-氨基-D-葡萄糖、氨基半乳糖、乳糖、葡萄糖、半乳糖、木糖、岩藻糖，含量比例为：6.88:5.13:5.19:70.78:1.47: 2.09:6.59:1.85；氨基酸含量为85.95%，甘氨酸、缬氨酸和谷氨酸所占比例较高；JGP-III2含有O-糖苷键和N-糖苷键，与海蜇体内获得的蛋白(gi|156215071)具有同源性。通过建立免疫低下小鼠模型，对JGP-III2的免疫活性及免疫机理进行研究，结果表明：与模型对照组比，JGP-III2能显著提高免疫低下小鼠的脾脏指数，胸腺指数，巨噬细胞吞噬能力，迟发性变态反应，血清溶血素水平及抗体生成细胞数，增强机体免疫能力。JGP-III2能促进Th1类细胞因子mRNA的表达，抑制Th2类细胞因子的mRNA的表达，对模型组中的“Th1/Th2漂移”现象有恢复作用。推测JGP-III2可能是通过调节机体Th1/Th2的平衡来提高机体免疫活性。

A new glycoprotein JGP-III2 was obtained from jellyfish. JGP-III2 is composed of 11.87% carbohydrate and 87.74% protein, which presents a molecular weight of 39.5 kDa. JGP-III2 is composed of eight types of monosaccharides: mannose, 2-amino-D-glucose, galactosamine, lactose, glucose, galactose, xylose, and fucose in a ratio of 6.88:5.13:5.19:70.78:1.47:2.09:6.59:1.85. The total amino acid content in JGP-III2 is 85.95%. Glycine is the major amino acid, followed by valine and glutamic acid. JGP-III2 presents N- and O-glycosidic bonds and is homologous to protein (gi|156215071) from Nematostella vectensis. The immune activity and immune mechanism of JGP-III2 were investigated using an immunocompromised mouse model. Compared with the control group, JGP-III2 significantly improved the spleen index, the thymus index, the phagocytic ability of the macrophages, serum hemolysin levels, and the number of antibody producing cells and delayed the allergic reaction in immunocompromised mice. The results showed that JGP-III2 could enhance the immune ability of these mice. Furthermore, JGP-III2 could promote the mRNA expression of Th1-type cytokines, inhibit the mRNA expression of Th2-type cytokines, and restore the “Th1/Th2 shift” found in the control group. JGP-III2 is considered to enhance the immune activity by regulating the Th1/Th2 balance.

国家自然科学基金资助项目（31000765）