C-type lectin 12B/4E of black rockfish (Sebastes schlegelii) macrophages as pattern recognition receptors in the antibacterial mechanism of exploration

As lower vertebrates, fish have both innate and adaptive immune systems, but the role of the adaptive immune system is limited, and the innate immune system plays an important role in the resistance to pathogen infection. C-type lectins (CLRs) are one of the major pattern recognition receptors (PRRs) of the innate immune system. CLRs can combine with pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) to trigger NF-κB signaling pathway and exert immune efficacy. In this study, Ssclec12b and Ssclec4e of the C-type lectins, were found to be significantly up-regulated in the transcripts of Sebastes schlegelii macrophages stimulated by bacteria. The identification, expression and function of these lectins were studied. In addition, the recombinant proteins of the above two CLRs were obtained by prokaryotic expression. We found that rSsCLEC12B and rSsCLEC4E could bind to a variety of bacteria in a Ca