Molecular characterization, expression and functional analysis of goldfish (Carassius aurutus L.) interferon gamma

We report on the characterization and functional analysis of IFN gamma of the goldfish. Quantitative analysis indicated the highest expression of goldfish IFN gamma in the spleen, with lower expressions in brain, gill, kidney, heart, intestine and muscle. An increase in IFN gamma expression was observed in kidney leukocytes following stimulation with PHA, PolyI:C and during mixed leukocyte reaction. IFN gamma was expressed in different goldfish immune cell populations and this expression was upregulated in several of these populations following treatment of cells with recombinant goldfish TNF alpha-2. A recombinant form of goldfish IFN gamma (rgIFN gamma) was produced and functionally analyzed. The rgIFN gamma primed goldfish macrophages and neutrophils for enhanced respiratory burst responses and increased the phagocytic and nitric oxide responses of macrophages. Furthermore, treatment of goldfish macrophages with rgIFN gamma induced increased expression of several proinflammatory genes including TNF alpha-1, TNF alpha-2, IL-beta-1, IL-beta-2. IL-12-p35, IL-12-p40, RSAD-2 (=viparin), CXCL-8 (=IL-8), CCL-1, NOS A and B and IFN gamma, and decreased the expression of TLR-3, while the expression of TGF beta remained unchanged. Our results indicate that IFN gamma is a central proinflammatory cytokine of teleosts. (C) 2008 Elsevier Ltd. All rights reserved.