Molecular Characterization and Gene Expression Analysis of CD74b in Red Sea Bream (Pagrus major)

The major histocompatibility complex class II-associated invariant chain is a molecule involved in antigen presentation, specifically in the context of T cells, which are effector cells of adaptive immunity. CD74 is a protein that reacts with MHC class II molecules and functions to transmit signals into cells by interacting with macrophage migration inhibitory factor. Red sea bream is one of the major marine aquaculture fish in Korea. Many studies on breeding but molecular studies are markedly lacking. In this study, CD74b was isolated from red sea bream (Pagrus major) and phylogenetic analysis, tissue expression and expression analysis through pathogen artificial infection were performed. As a result, it showed high expression in gills, brain and intestine. In addition, when analyzing Edwardsiella piscicida, Streptococcus iniae, and red sea bream iridovirus, it was confirmed that CD74b has an immune response function. This study characterizes CD74b may play an important role in the immune response of red sea bream following pathogenic infections.