Identification, expression and immunological responses to bacterial challenge following vaccination of BLT1 gene from turbot, Scophthalmus maximus

Abstract

Leukotriene B4 (LTB4) is well known as a chemoattractant for leucocytes, recent studies also showed its involvement in adaptive immunity. The purpose of this work is to report the cloning, characterization and gene expression of leukotriene B4 receptor (BLT1) in turbot (Scophthalmus maximus), as well as the immunological response to challenge following vaccination with a live attenuated vaccine Vibrio anguillarum MVAV6203. The full cDNA sequence of turbot BLT1 was cloned. The open reading frame consists of 1119bp nucleotides, which translate into 372 amino acid protein. A high conservation of amino acid sequence was found in the seven transmembrane (TM) domains and intracellular loops. The intracellular loop 3 consisting of a unique cluster of basic amino acid residues might be associated with signal transduction. High amino acid similarity and a phylogenetic tree confirmed it as a leukotriene B4 receptor member. The BLT1 gene is expressed in a wide range of tissues with the highest expression in kidney followed by spleen. The expression of turbot BLT1 was significantly up-regulated in spleen, gut and gill after vaccination and in kidney and skin after challenge. These results suggest a potential role of turbot BLT1 in protection against infection.