我们在前期工作中发现七鳃鳗血液中存在一种能够识别细菌表面的脂多糖和肽聚糖并发挥凝集病原菌功能的蛋白质LIP。同时发现，七鳃鳗接受大肠杆菌刺激后VLRB+类淋巴细胞出现明显增殖现象。上述线索提示LIP和VLRB+类淋巴细胞在七鳃鳗抵御病原菌入侵过程中起到重要作用。本课题在前期研究基础上，拟以原位杂交和免疫组化法分析LIP在七鳃鳗主要组织的分布情况；采用ITC等方法确定LIP识别病原菌的方式；以CRISPR/Cas9法建立七鳃鳗LIP基因敲除动物模型研究缺失LIP基因后经病原菌刺激VLRB+类淋巴细胞的表达差异情况。最终确定七鳃鳗LIP识别病原菌，激活VLRB+类淋巴细胞的分子机制。上述研究将为完善脊椎动物免疫防御体系研究提供新思路；同时也为更好的了解人类免疫防御体系起源与演化历程提供了关键线索。

Previous studies have shown that a novel protein LIP found in lamprey blood was capable of binding to bacterial Lipopolysaccharide (LPS) and Peptidoglycan (PGN) to induce pathogens aggregation. Meanwhile, the proliferation of VLRB+ lymphocyte-like cells was found obviously after the animals were stimulated with Escherichia coli. These clues suggested that LIP and VLRB+ lymphocyte-like cells may play important roles in the resistance of the pathogens invasion. In this project, in situ hybridization and immunohistochemistry will be used to analyze the localizations of LIP in immune associated tissues of lampreys based on the previous studies described above. LIP mediated pathogens recognition will be confirmed by using ITC analysis. The expression of VLRB+ lymphocyte-like cells is analyzed by CRISPR/Cas9 technology mediated LIP gene knockout assay. All these researches have important significance in explaining the molecular mechanism of LIP which mediates pathogens recognition and activates VLRB+ lymphocyte-like cells in lamprey. This project will provide new information on the vertebrate immune defense system, and providing valuable clues for studying the origin and evolution of human immune system.