Characterization and Immune Functions of LcβLectin from Large Yellow Croaker (Larimichthys crocea): A Potential Antiviral Defense Molecule

Large yellow croaker iridovirus (LYCIV) poses a significant threat to the large yellow croaker (Larimichthys crocea) aquaculture industry due to its rapid transmission and high lethality. Galectins, as evolutionarily conserved carbohydrate-binding lectins and pattern recognition receptors (PRRs) in the innate immune system, play crucial roles in immune responses. In this study, we characterized the beta-galactoside-binding lectin from large yellow croaker (Lc beta Lectin) and explored its potential as a disease resistance gene against LYCIV. The full-length cDNA of Lc beta Lectin was cloned and found to contain conserved elements, such as beta-galactoside-binding motifs, HNPR, and WCEEHR domains. Using L. crocea head-kidney macrophages (LCM10), we demonstrated that recombinant Lc beta Lectin significantly inhibits LYCIV-induced cytopathic effects and reduces macrophage apoptosis, highlighting its key role in viral defense. Moreover, the overexpression of Lc beta Lectin in LCM10 cells followed by transcriptomic analysis revealed its substantial regulatory effects on key immune-related signaling pathways, including C-type lectin signaling, p53 signaling, and Toll-like receptor signaling pathways. Collectively, our findings suggest that Lc beta Lectin enhances fish resistance to viral diseases by augmenting immune system function and activating immune-related pathways, providing valuable insights into the innate immune mechanisms of aquatic species and potential strategies for disease prevention in aquaculture.