Characterisation and quantification of equine interferon gamma

Interferon-γ (IFN-γ) is a key cytokine in cell-mediated immunity. To measure IFN-γ production of equine lymphocytes (eqIFN-γ), we developed a quantitative ELISA. Monoclonal antibodies (mAb) were produced against bacterially derived eqIFN-γ. The mAbs recognised recombinant and lymphocyte-derived eqIFN-γ in ELISA, Western blotting, as well as flow cytometric and microscopic analysis. In contrast to bacterially derived material, mammalian and insect cell-derived eqIFN-γ was biologically active but could be neutralised by one of the monoclonal antibodies. Unexpectedly, glycosylation seemed to be required for antiviral activity of eqIFN-γ.