Rainbow trout (Oncorhynchus mykiss) recombinant IL-1β and derived peptides induce migration of head-kidney leucocytes in vitro

The present work provides the first information concerning the chemoattractant activity of trout recombinant IL-1 beta and its derived peptides, referred to as P1, P2 and P3. The predicted rainbow trout mature interleukin-1 beta peptide was produced as a recombinant protein in Escherichia coh. The first peptide, P1, corresponded to fragment 146-157 (YVTPVPIETEAR) of the trout sequence and had an MW of 1.37 kDa. It was equivalent to a region known to be part of the receptor binding domain from the mammalian crystal structure of IL-1 beta complexed to its receptor. P2 was used as control peptide, consisting of the same 12 amino acids as P1, but arranged in a random sequence (VVEEYIRAPPTT). P3 was synthesised to complex with an adjacent region of the IL-1 receptor, and corresponded to fragment 207-216 (YRRNTGVDIS) of the trout sequence, with an MW of 1.18 kDa. Migration was stimulated when leucocytes were exposed to concentrations of greater than or equal to 10 ng ml(-1) rIL-1 beta. Peptide P3 also induced leucocyte migration, with an optimal dose of 0.25 mm being recorded. While P1 had no effect on cell migration when used alone, synergism was evident as a consequence of combining P1 with a suboptimal dose (0.01 mm) of P3. No synergism occurred when cells were exposed to a combination of P3 and the control peptide P2. (C) 2001 Academic Press.