PcLT, a novel C-type lectin from Procambarus clarkii, is involved in the innate defense against Vibrio alginolyticus and WSSV

Lectins play important roles in the innate immunity. In this work, a C-type lectin, PcLT, was obtained from Procambarus clarkii which contained a carbohydrate recognition domain (CRD) with the ability to bind to Vibrio alginolyticus and white spot syndrome virus (WSSV). RT-PCR and qRT-PCR analyses demonstrated PcLT was specifically expressed in the hepatopancreas and the mRNA was markedly upregulated by V. alginolyticus and WSSV challenge, although a slight difference in timing was observed. The study also revealed upregulation of the mRNA expression and activity of immunological factors, peroxinectin, phenoloxidase, and superoxide dismutase in hemolymph in response to recombinant PcLT (rPcLT). Moreover, rPcLT also enhanced the phagocytosis, facilitated the subsequent clearance of V. alginolyticus and prolonged the survival of WSSV-infected shrimp. These results suggested that PcLT not only served as a pathogen recognition receptor (PRR), but also functioned as an immune modulator, participating in host defense against invaders.

► PcLT serves not only as a pathogen recognition receptor (PRR), but also as an immune modulator.
► PcLT takes part in regulating both humoral and cellular reactions after pathogen invasion.
► We speculate the mechanisms that PcLT protects shrimp from bacterial and viral infections are different.