Differential expression of two interferon-γ genes in common carp (Cyprinus carpio L.)

SummaryTwo interferon gamma (IFN-γ) genes are expressed in immune cells of teleost fish and are potentially implicated in B- and T-lymphocyte responses. IFN-γ-2 shows structural and functional characteristics to other vertebrate IFN-γ genes and is associated with T-lymphocyte function. Expression profiling shows IFN-γ-2 upregulation in T-lymphocytes after phytohemagglutinin (PHA) stimulation in vitro. Unexpectedly, we found IFN-γ-1, which is structurally different from IFN-γ-2, to be expressed in lipopolysacharide (LPS)-stimulated IgM+ (B- lymphocyte enriched) fractions. Expression of T-box transcription factor T-bet, but not of GATA-binding protein 3 (GATA3), correlated with expression of both IFN-γ genes. In-vivo parasite infection, but as predicted not zymosan-induced inflammation, resulted in concomitant upregulation of T-bet and IFN-γ-2. This corroborates a genuine T-lymphocyte associated role for IFN-γ-2.