title: Recombinant transferrin induces nitric oxide response in goldfish and murine macrophages.
abstract: We have previously demonstrated that the serum protein transferrin plays a key role in the activation of primary goldfish macrophages. The ability of this protein to activate goldfish macrophages was also shown to be dependent on enzymatic cleavage of the native (i.e. full-length) protein into immunostimulatory fragments. In this study, we report that immunostimulatory fragments of recombinant goldfish transferrin (rGTf), induced a potent nitric oxide (NO) response in goldfish as well as in murine macrophages. Specifically, recombinant goldfish transferrin N- and C-lobe fragments expressed in Escherichia coli induced the NO response in goldfish and murine macrophages. As little as 75-150 ng of the recombinant proteins (N- or C-lobe) had biological activity, even in the presence of 10 microg/ml of the LPS inhibitor polymixin B sulphate (PMB). These findings indicate that transferrin is a key conserved component required for induction of macrophage antimicrobial responses of fish and provide evidence that a similar induction pathway exists in mammals, which has not been reported previously.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9.
authors.forename: James L
authors.initials: JL
authors.lastname: Stafford
authors.forename: Elaine C
authors.initials: EC
authors.lastname: Wilson
authors.forename: Miodrag
authors.initials: M
authors.lastname: Belosevic
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D017931:DNA Primers; D004926:Escherichia coli / Q000378:metabolism; D005822:Genetic Vectors; D006054:Goldfish / Q000276:immunology* / Q000378:metabolism; D007668:Kidney / Q000276:immunology; D007962:Leukocytes / Q000276:immunology; D008264:Macrophages / Q000187:drug effects*; D051379:Mice / Q000276:immunology* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D014168:Transferrin / Q000235:genetics / Q000494:pharmacology*; D014169:Transformation, Bacterial
chemical_list: D000276:Adjuvants, Immunologic; D017931:DNA Primers; D011994:Recombinant Proteins; D014168:Transferrin; D009569:Nitric Oxide