A biologically active IL‐1β derived peptide stimulates phagocytosis and bactericidal activity in rainbow trout, Oncorhynchus mykiss (Walbaum), head kidney leucocytes in vitro

Abstract

The present work provides the first information concerning the ability of a rainbow trout interleukin‐1β (IL‐1β) derived peptide, P3, to enhance phagocytosis and bactericidal activity. P3 was synthesized to complex with the IL‐1 receptor and corresponds to fragment 197–206 (YRRNTGVDIS) of the trout sequence. A dose‐dependent effect of P3 on phagocytosis in head kidney leucocytes was documented, with an optimal response occurring at 0.25 mM. With respect to the temporal kinetics of P3 induced activation, an incubation period of 2 h resulted in enhanced phagocytic activity, although incubation times of between 4 and 24 h were optimal. An additive effect was observed when P3 (0.1 mM) was combined with another IL‐1 derived peptide, P1 (0.1 mM). The latter peptide corresponds to fragment 146–157 (YVTPVPIETEAR) and is equivalent to a region in the mammalian protein that is known to be part of the receptor binding domain, but does not overlap with P3. With respect to bactericidal activity, macrophages incubated for 24 h with 0.1 mM P3 demonstrated an enhanced ability to kill an avirulent strain (MT004) of the Gram‐negative salmonid pathogen Aeromonas salmonicida. Further investigation revealed that extracellular production of superoxide anions was not responsible for the enhanced bactericidal activity of macrophages exposed to P3.

Influence of Stress and Dietary Natural‐Source Vitamin E on Nonspecific Immunocompetence, Tissue Tocopherol Composition, and Postslaughter Fillet Oxidative Stability in Sunshine Bass

“…Macrophage bactericidal activity was measured on stock cultures of Micrococcus lysodeiktus according to a protocol adapted from Peddie et al (2002). Macrophage monolayer microplates prepared as previously described were inoculated with stock M. lysodeiktus culture in tryptic soy broth (TSB).…”

Effect of intraperitoneally administered IL-1b-derived peptides on resistance to viral haemorrhagic septicaemia in rainbow trout Oncorhynchus mykiss

“…Peptides derived from the trout IL-1β molecule have recently been synthesised and tested for their bioactivity in vitro (Peddie et al , 2002a. The most bioactive peptide, known as P3, was synthesised to complex with the IL-1 receptor and corresponds to fragment 197-206 (YRRNTGVDIS) of the trout sequence.…”

“…Optimal migration of peritoneal leucocytes, peptide induced phagocytosis and intracellular respiratory burst activity occurred following intraperitoneal injection of 3.0 µmol of P3. Furthermore, resistance to viral haemorrhagic septicaemia virus (VHSV) was soon augmented (2 d) post-injection of P3.KEY WORDS: Interleukin-1β · Phagocytosis · Respiratory burst · Disease resistance · Immunomodulation · VHS 56: 195-200, 2003 cytes (Peddie et al 2002a). Although bioactive in its own right, the ability of P1 to enhance leucocyte migration and phagocytosis is enhanced when it is combined with P3 (Peddie et al , 2002a.…”

“…KEY WORDS: Interleukin-1β · Phagocytosis · Respiratory burst · Disease resistance · Immunomodulation · VHS 56: 195-200, 2003 cytes (Peddie et al 2002a). Although bioactive in its own right, the ability of P1 to enhance leucocyte migration and phagocytosis is enhanced when it is combined with P3 (Peddie et al , 2002a.…”

“…Although bioactive in its own right, the ability of P1 to enhance leucocyte migration and phagocytosis is enhanced when it is combined with P3 (Peddie et al , 2002a.…”