基于RAGs、BCR、TCR和CD分子的时空表达评估罗非鱼淋巴细胞的分化节点及其初步应用

在RAGs、BCR、TCR、CD分子等基因有序参与下，淋巴细胞逐步分化，这些基因可指示淋巴细胞分化状态，其异常可导致多种免疫缺陷。目前在罗非鱼中未见对淋巴细胞发育分化的研究报道，申报人在前期已克隆得到尼罗罗非鱼（Oreochromis niloticus）的RAGs基因，并且发现其在发育早期主要在胸腺表达，在成体中主要在胸腺和头肾表达。我们计划在不同发育时期的罗非鱼中，通过原位杂交、免疫组织化学、qPCR等技术研究上述基因的时空表达图式，评估其淋巴细胞分化的时间节点。然后，在罗非鱼感染无乳链球菌（Streptococcus agalactiae）后，检测不同淋巴细胞标记基因的表达变化和淋巴细胞的空间定位，阐明在感染后罗非鱼特异性免疫系统的免疫应答途径。并根据上述研究确立罗非鱼链球菌病的参考免疫时机。该研究将加深我们对罗非鱼淋巴细胞发育和分化的认识，同时为链球菌病的防控提新的思路。

Lymphocyte differentiated gradually with the orderly participation of RAGs, BCR, TCR, and CD molecule gene. The expression of these genes can indicate the differentiation state of lymphocyte, and their mutation may result in a variety of immunodeficiency. At present, there is no research on the lymphocyte development and differentiation in tilapia. The RAGs gene of Nile tilapia (Oreochromis niloticus) have been cloned in our preliminary work. The expression analysis of tilapia RAGs showed that RAGs expressed mainly in thymus during the early development stage and both in thymus and head kidney in adult. We plan to study the spatio-temporal expression pattern of RAGs, BCR, TCR, and CD molecule gene to evaluate the differentiation nodes of lymphocyte in different development stage of tilapia. The changes on expression level of lymphocyte marker genes and the spatial location of lymphocytes will be detected to expound the immune response pathway activated by Streptococcus agalactiae in tilapia. The reference immune time of tilapia streptococcus disease will be established according to above research. The study will deepen our understanding of the development and differentiation of lymphocytes in tilapia, and provide new ideas for the prevention and control of Streptococcus disease.