Characterization and Expression Analysis of the C-Type Lectin Ladderlectin in Litopenaeus vannamei Post-WSSV Infection

C-type lectins are known for agglutination activity and play crucial roles in regulating the prophenoloxidase (proPO) activation system, enhancing phagocytosis and encapsulation, synthesizing antimicrobial peptides, and mediating antiviral immune responses. This work cloned a C-type lectin, ladderlectin ( ), from . comprised a 531 bp open reading frame (ORF) that encoded 176 amino acids. The predicted LvLL protein included a signal peptide and a CLECT domain. LvLL was predicted to feature a transmembrane region, suggesting it may be a transmembrane protein. was predominantly expressed in the shrimp's hepatopancreas. After WSSV infection, expression in the hepatopancreas increased significantly by 11.35-fold after 228 h, indicating a general upregulation. Knockdown of resulted in a significant decrease in WSSV viral load and a notable increase in shrimp survival rates. Additionally, knockdown of led to a significant downregulation of apoptosis-related genes and caspase 8 and a significant upregulation of and in WSSV-infected shrimp. This study showed that played a vital role in the interaction between . and WSSV.