Protective immune responses of recombinant outer membrane proteins OmpF and OmpK of Aeromonas hydrophila in European eel (Anguilla anguilla)

The suppressor of cytokine signaling (SOCS) family members play crucial roles in regulating immune signal pathways by acting as inhibitors of cytokine receptor signaling. In this study, 10 SOCS genes were identified in soiny mullet (Liza haematocheila), an economically important aquaculture mugilid species in China and other Asian countries. Sequence comparison showed that the sequence identity between mullet SOCSs and their counterparts from other vertebrates ranged from 38.2% to 92.5%. All mullet SOCS genes were constitutively expressed in tissues examined, but their expression patterns were different. Further, following Streptococcus dysgalactiae infection, all mullet SOCS genes exhibited distinct expression patterns in tissues. These results suggest that SOCSs are involved in immune response to bacterial infection and provide the basis for understanding the complex cytokine regulatory network of teleosts.