The intracellular domain of the second chain of the interferon-gamma receptor is interchangeable between species.

In this report we show that the mouse interferon (IFN)-gamma R1 and IFN-gamma R2 subunits expressed in hamster cells are capable of rendering the cells sensitive to mouse IFN-gamma as measured by induction of class I MHC antigens and the activation of the transcription factor Stat1 alpha. However, these cells showed no antiviral protection in response to IFN-gamma when challenged with vesicular stomatitis virus (VSV) but limited protection when challenged with encephalomyocarditis virus (EMCV). Furthermore, the cytoplasmic domains of the IFN-gamma R2 subunits, like the cytoplasmic domains of the IFN-gamma R1 chains, can be interchanged between species with no loss of biologic activity, demonstrating that the species-specific interaction of the IFN-gamma R1 and IFN-gamma R2 chains involves only the extracellular domains of the two proteins.