A novel C-type lectin (FcLec4) facilitates the clearance of Vibrio anguillarum in vivo in Chinese white shrimp

C-type lectins play important roles in innate immunity of invertebrates. In the present study, we report a novel C-type lectin, named FcLec4, from the Chinese white shrimp Fenneropenaeus chinensis. FcLec4 contains a single carbohydrate recognition domain (CRD) with a putative signal peptide. Phylogenetic analysis indicated that FcLec4 was distant from most reported C-type lectins from shrimps. The expression of FcLec4 increased at both mRNA and protein level after stimulation of Vibrio anguillarum. Recombinant FcLec4 could agglutinate both Gram-positive and -negative bacteria in the presence of calcium. The recombinant protein could bind to peptidoglycan and selectively bind to microorganisms. Interestingly, the tight binding of recombinant FcLec4 to V. anguillarum might facilitate the subsequent clearance of the bacteria in vivo. To the best of our knowledge, this might be the first report that a C-type lectin was found to be directly involved in the anti-V. anguillarum response in shrimps.