Abstract：
Crustin are a family of antimicrobial peptides that play an important role in protecting against pathogens infection in the innate immune system of crustaceans. Previously, we identified several novel types of crustins, including type VI and type VII crustins. However, their immune functions were still unclear. In the present study, the immune function of type VII crustin LvCrustinVII were investigated in Litopenaeus vannamei. LvCrustinVII was wildly expressed in all tested tissues, with relatively high expression levels in hepatopancreas, epidermis and lymphoid organ. Upon Vibrio parahaemolyticus infection, LvCrustinVII was significantly upregulated in hepatopancreas. Recombinant LvCrustinVII (rLvCrustinVII) showed strong inhibitory activities against Gram-negative bacteria Vibrio harveyi and V. parahaemolyticus, while weak activities against the Gram-positive bacteria Staphylococcus aureus. Binding assay showed that rLvCrustinVII could bind strongly to V. harveyi and V. parahaemolyticus, as well as the cell wall components Glu, LPS and PGN. In the presence of Ca2+, rLvCrustinVII could agglutinate V. parahaemolyticus and enhance hemocyte phagocytosis. The present data partially illustrate the immune function of LvCrustinVII, which enrich our understanding on the functional mechanisms of crustins and provide useful information for application of this kind of antimicrobial peptides.
摘要：
Crustin是一类抗菌肽，在保护甲壳类动物的先天免疫系统免受病原体感染中起着重要作用。以前,我们发现了几种新型的地壳,包括VI型和VII型地壳。然而,他们的免疫功能仍不清楚.在本研究中,在凡纳滨对虾中研究了VII型crustinLvCrustinVII的免疫功能。LvCrustinVII在所有测试组织中广泛表达，在肝胰腺中表达水平相对较高，表皮和淋巴器官。副溶血性弧菌感染后，LvCrustinVII在肝胰腺中明显上调。重组LvCrustinVII(rLvCrustinVII)对革兰氏阴性菌哈维氏弧菌和副溶血性弧菌表现出较强的抑制活性，而对革兰氏阳性菌金黄色葡萄球菌的活性较弱。结合实验表明，rLvCrustinVII可以与哈维伊氏弧菌和副溶血性弧菌强结合，以及细胞壁成分Glu，LPS和PGN。在Ca2+的存在下，rLvCrustinVII可以凝集副溶血弧菌并增强血细胞吞噬。目前的数据部分说明了LvCrustinVII的免疫功能，这丰富了我们对结壳蛋白功能机制的理解，为这种抗菌肽的应用提供了有用的信息。
