Molecular characterization and expression analysis of three interleukins (IL‐1β, IL‐15 and IL‐16) in largemouth bass (Micropterus salmoides)

Interleukins (ILs) are a subgroup of cytokines involved in the intercellular regulation of the immune system, which play important roles in host immune defense against pathogens. In the present study, three ILs (IL-1β, IL-15 and IL-16) were identified from largemouth bass (Micropterus salmoides), an economically important freshwater fish species. The three ILs, which shared characteristic features with their counterparts in other fish species, were ubiquitously expressed in all the examined tissues, but with different expression patterns. Following lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid (polyI:C) stimulation, all the three genes were up-regulated to different degrees in spleen of largemouth bass. The results indicated that these ILs involved in the immune response of largemouth bass during bacterial and virus infection. To the best of our knowledge, this is the first characterization of these three genes in largemouth bass. Our results will not only enrich the understanding of interleukins in largemouth bass, but also provide a valuable framework for further studies of the immune function of these interleukins during pathogen invasion.