Molecular characterization of TNF-? and IFN-γ in yellowfin seabream (Acanthopagrus latus, Hottuyn, 1782) and their immune responses to density stress during transport

作者：Liang, Yu; Zhu, Ke-Cheng; You, Ying-Zhe; Guo, Hua-Yang; Chen, He-Dong; Liu, Bao-Suo; Zhang, Nan; Dai, Yan-Bin; Zeng, Fan-Rong; Lin, Huan-Yang; Zhang, Dian-Chang^*

来源：Developmental and Comparative Immunology, 2023, 147: 104747.

DOI：10.1016/j.dci.2023.104747

• Acanthopagrus latus
• TNF-ss
• IFN-gamma
• Density stress

The inflammatory cytokines TNF-ss and IFN-gamma are important mediators of the vertebrate inflammatory response and coordinators of the immune system in regard to NF-kappa B signalling pathways. In this study, the TNF-ss and IFN-gamma genes of yellowfin seabream, Acanthopagrus latus were identified, and the multiple sequence alignments, evolutionary relationships and gene expressions of the two genes were also determined. AlTNF-ss contained a 762 bp open reading frame (ORF) encoding 253 amino acids, while AlIFN-gamma contained a 582 bp ORF encoding 193 amino acids. An amino-acid sequence alignment analysis showed that these proteins have highly conserved transmembrane structural domains among teleosts. Moreover, AlTNF-ss has a close affinity with TNF-ss of yellowfin seabream while AlIFN-gamma has a high evolutionary correlation with A. regius and Sparus aurata. In addition, the mRNAs of AlTNF-ss and AlIFN-gamma are widely expressed in various tissues. AlTNF-ss is highly expressed in gill and intestinal tissues, and the mRNA levels of AlIFN-gamma are higher in spleen, skin, and gill tissues than in other tissues. Under transportation density stress, the mRNA level of AlTNF-ss was significantly elevated in the intestine of the high-density group, while AlTNF-ss transcription in the gills did not vary significantly among the density groups. Furthermore, AlIFN-gamma expression was increased in liver, intestinal, and gill tissues under high transportation density. The results of this study show that TNF-ss and IFN-gamma expression in yellowfin seabream is greatly affected by density stress. The density of 125 per bag for 4-5 cm fry or 1200 per bag for 1-2 cm fry is most suitable for the transportation of live fish. These results might provide a reference for further studies on the immunomodulatory response process and auxiliary function of immune stress of TNF and IFN genes in fish under density stress.