Identification of a Novel IL-1 Cytokine Family Member in Teleost Fish

Abstract

A novel IL-1 family member (nIL-1F) has been discovered in fish, adding a further member to this cytokine family. The unique gene organization of nIL-1F, together with its location in the genome and low homology to known family members, suggests that this molecule is not homologous to known IL-1F. Nevertheless, it contains a predicted C-terminal β-trefoil structure, an IL-1F signature region within the final exon, a potential IL-1 converting enzyme cut site, and its expression level is clearly increased following infection, or stimulation of macrophages with LPS or IL-1β. A thrombin cut site is also present and may have functional relevance. The C-terminal recombinant protein antagonized the effects of rainbow trout rIL-1β on inflammatory gene expression in a trout macrophage cell line, suggesting it is an IL-1β antagonist. Modeling studies confirmed that nIL-1F has the potential to bind to the trout IL-1RI receptor protein, and may be a novel IL-1 receptor antagonist.

Identification and expression analysis of an atypical chemokine receptor-2 (ACKR2)/CC chemokine binding protein-2 (CCBP2) in rainbow trout (Oncorhynchus mykiss)

“…IL-6, TNF-a and IL-1b) is highly upregulated [40,42,56]. The transient down-regulation of the scavenger ACKR2 by PAMPs may enhance the release of chemokines to attract immune cells to a site of infection.…”

Cloning of two rainbow trout nucleotide-binding oligomerization domain containing 2 (NOD2) splice variants and functional characterization of the NOD2 effector domains

“…NP_001118119). The primer sequences of IFN1 and IFN2 were reported by Zou et al [19], IFN-g1 by Díaz-Rosales et al [33], IL-1b1 and IL-8 by Wang et al [34]. The primer sequences of other genes are listed in Table 1.…”

Functional Characterization of a Nonmammalian IL-21: Rainbow Trout Oncorhynchus mykiss IL-21 Upregulates the Expression of the Th Cell Signature Cytokines IFN-γ, IL-10, and IL-22

“…The pET-tIL-21 was transformed into E. coli BL21 Star (DE3) competent cells (Invitrogen) and induced during exponential growth with 1 mM isopropyl 1-thio-b-D-galactopyranoside (IPTG) for 4 h prior to harvest. The recombinant protein was purified under denaturing conditions as previously described (42), refolded in a buffer containing 0.5 M arginine, and repurified under native conditions giving a high concentration of pure recombinant protein (0.5-2 mg/ml) (47). The purified rtIL-21 was added to the monocyte/macrophage-like RTS-11 cell line (53), HK cells, and splenocytes to examine its bioactivity.…”

“…The preparation of bacterial cells and infection protocol was as described previously (46,47). Two weeks before bacterial challenge, rainbow trout of ∼100 g were transferred into two tanks (30 fish/tank) in the freshwater aquarium pathogen containment facility at the School of Biological Sciences, University of Aberdeen.…”