Bipolar properties of red seabream (Pagrus major) transforming growth factor-β in induction of the leucocytes migration

TGF-β is one of the pleiotropic cytokines and plays a pivotal role in immune regulation and orchestrating the subsequent healing response. Recombinant red seabream TGF-β (rTGF-β) mature peptide was expressed and purified under native conditions in vitro. Bio-assay showed that the rTGF-β could significantly induce head kidney (HK) and peripheral blood (PB) leucocytes migration in a dose dependent manner, whereas the rTGF-β suppressed HK and PB leucocyte migration when the leucocytes was activated by primed with lipopolysaccharide (LPS). Both enhancing and suppressing roles of rTGF-β on the HKL and PBL chemotactic activity indicated that the fish TGF-β shared the similar bipolar nature with mammalian TGF-β. Furthermore, the results indicated that the activity of TGF-β induction of leucocyte migration appears not to be an innate feature but function by regulation the chemokines activity. This is the first time we reported that fish TGF-β has innate bipolar property in regulation of fish immune function.