IL-10 cytokine family belongs to type Ⅱhelix cytokine, which has many common characteristics and different biological functions. In this paper, the IL-10 and IL-20L genes in the IL-10 family of swamp eel (Monopterus albus) were characterized for the first time, and their expression patterns after stimulation by Aeromonas veronii were studied. Through phylogenetic tree, amino acid sequence alignment and similarity analysis, eel IL-10 and IL-20 were the closest to their counterparts of tilapia, and fish IL-20L molecules were clustered into a branch alone, and then converged with IL-19/IL-20/IL-24 of higher vertebrates. There are two conserved motifs in eel IL-10 and IL-20L, and the motif in IL-10 is completely consistent with the conserved signature motif of IL-10 family. Eel IL-10 has 6 α helices and 4 conserved cysteines, and IL-20 has 5 α helices and 6 conserved cysteines, in which helix E′ is equivalent to helices E and F of IL-10. These results indicate that fish IL-10 and IL-20L cytokines were evolutionarily conservative. The gene structure of IL-10 and IL-20 of all selected species consists of five coding exons and four 0-phase introns, which are closely linked at the corresponding loci. Our study supports the hypothesis that the IL-20 subfamily cytokines share a common origin with IL-10. Whether it is tissue expression or induced expression, eel IL-10 has a higher expression level than IL-20L, but both of them may be involved in the late stage of the host's response to bacterial infection, and there are differences between them and other fish expression patterns. It is hoped that these research results will help to understand the immune system of fish and formulate disease prevention and control measures.

IL-10细胞因子家族属于Ⅱ型螺旋细胞因子，具有许多共同特征和不同的生物学功能。本文首次对沼泽鳗（ Monopterus albus ） IL-10家族的IL-10和IL-20L基因进行了表征，以及它们在维罗尼气单胞菌刺激后的表达模式。进行了研究。通过系统发育树、氨基酸序列比对和相似性分析，鳗鱼IL-10和IL-20与罗非鱼的对应物最接近，鱼类IL-20L分子单独聚集成一个分支，然后与IL-19/高等脊椎动物的 IL-20/IL-24。鳗鱼IL-10和IL-20L中有两个保守基序，IL-10中的基序与IL-10家族的保守特征基序完全一致。鳗鱼IL-10有6个α螺旋和4个保守半胱氨酸，IL-20有5个α螺旋和6个保守半胱氨酸，其中螺旋E'相当于IL-10的螺旋E和F。这些结果表明鱼的 IL-10 和 IL-20L 细胞因子在进化上是保守的。IL-10和IL-20的基因结构所有选定物种的基因组由 5 个编码外显子和 4 个 0 相内含子组成，它们在相应的基因座上紧密相连。我们的研究支持 IL-20 亚家族细胞因子与 IL-10 具有共同起源的假设。无论是组织表达还是诱导表达，鳗鱼IL-10的表达水平都高于IL-20L，但两者都可能参与宿主对细菌感染反应的后期，与其他的存在差异。鱼的表达模式。希望这些研究成果有助于了解鱼类的免疫系统，制定疾病防控措施。