B cell activating factor (BAFF) is recognized as a member of the TNF superfamily proteins that mediate the immune responses. In this study, BAFF from rockfish (Sebastes schlegelii) (SsBAFF) was characterized based on its functional aspects. The open reading frame of SsBAFF is 804 bp in length and encodes a 267 long amino acid residue protein with predicted molecular weight of 29.48 kDa. The deduced protein sequence comprises with transmembrane domain, furin cleavage site and TNF domain carrying Flap binding site that unique to TNF family. Recombinant SsBAFF (rSsBAFF) significantly enhanced rockfish lymphocytes proliferation and viability in a concentration dependent-manner according to the results from water soluble tetrazolium salt (WST-1) assay and flow cytometric assay. rSsBAFF also modulated the expression of genes involved in anti-inflammatory (IL-10 and NFκB-2) and anti-apoptotic (Bcl-2 and Bax) signal pathways. SsBAFF mRNA expression was detected ubiquitously in all analyzed rockfish tissues, with the highest levels in the spleen and head kidney. Further, the expression of SsBAFF in spleen were significantly induced following LPS, poly (I:C) and Streptococcus iniae challenges. These findings strongly suggest that SsBAFF might play an important role in rockfish immune system through regulating the inflammatory response and proliferation of immune cells.

B细胞活化因子（BAFF）被认为是介导免疫反应的TNF超家族蛋白的成员。在这项研究中，基于其功能方面对石斑鱼（Sebastes schlegelii）（SsBAFF）的BAFF进行了表征。SsBAFF的开放阅读框架长度为804 bp，编码267个长氨基酸残基蛋白，预测分子量为29.48 kDa。推导的蛋白质序列包括跨膜结构域，弗林蛋白酶切割位点和带有TNF家族独特的带有Flap结合位点的TNF结构域。重组SsBAFF（rSsBAFF）根据水溶性四唑盐（WST-1）测定和流式细胞仪测定的结果，以浓度依赖性方式显着增强了石鱼淋巴细胞的增殖和活力。rSsBAFF还调节抗炎（IL-10和NFκB-2）和抗凋亡（Bcl-2和Bax）信号通路相关基因的表达。斯巴夫在所有分析的石鱼组织中普遍检测到mRNA表达，其中脾脏和头肾中的mRNA水平最高。此外，表达SsBAFF在脾脏显著诱导以下LPS，聚（I：C）和海豚链球菌挑战。这些发现强烈表明，SsBAFF可能通过调节炎症反应和免疫细胞的增殖而在石鱼的免疫系统中发挥重要作用。