Interleukin-10 expression by real-time PCR and homology modelling analysis in the European sea bass (Dicentrarchus Labrax L.)

In this paper we investigate the interleukin-10 (IL-10) expression and 3D modelling of the European sea bass (Dicentrarchus labrax L.). IL-10 is a regulatory cytokine that has been intensively studied in mammals and has been found mainly involved in the suppression or deactivation of activated immune responses. The full-length sea bass IL-10 cDNA consists of 1015 bp and is translated in a predicted molecule of 187 amino acids. A multiple alignment of this peptide with other known sequences showed the conservation of fundamental IL-10 family characteristics. Expression analysis by real-time PCR in control fish showed a high basal expression in the head kidney (HK), followed by gut and brain. In vitro treatment of HK leucocytes with LPS showed an intense increase of IL-10 expression at 4 h and a significant decrease at 24 h, with PHA-L no differences were evidenced. A 3D model for sea bass IL-10 was obtained by accurate homology procedures and putative interaction residues with the IL-10 receptor described. The results suggested that sea bass IL-10 could be involved in anti-inflammatory responses, but further experiments are needed to assess its importance in response to pathogenic agents, vaccinations and immunostimulants.