Interferon-gamma (IFN-γ), also known as Type II interferon or immune interferon, is a pleiotropic cytokine which is now recognised as an important modulator of the immune response. Mature human IFN-γ exists as a non-covalently linked homodimer of 20-25 kDa variably glycosylated subunits. It shares 90% amino acid (aa) sequence identity with rhesus IFN-γ, 59%_x001e_64% with bovine, canine, equine, feline, and porcine IFN-γ, and 37%43% with cotton rat, mouse, and rat IFN-γ. Interferons have had increasing clinical usage in the treatment of a variety of disorders, at times being used in combination with chemo‐ or radiotherapy. IFN-γ increases the potential immunogenicity of vascular endothelial cells by up-regulation of intercellular adhesion molecule-1 (ICAM-1) and class I MHC antigen expression and by induction of class II MHC antigens and certain chemokines.