Engineered acid-stabile human interferon gamma.

Abstract Loss of anti-viral potency upon pH2-treatment is an inherent feature of interferon (IFN)-γ. The phenomenon seems to be caused by dissociation of IFN-γ homodimer into subunits upon acidification and subsequent self-association of monomers into aggregates with reduced activity after neutralization. We demonstrated that acid-stability could be engineered into human IFN-γ without affecting its specific activity. An artificial intra-monomer disulphide bond E7C/S69C stabilizes the dimeric form of the cytokine, which retained its full bioactivity after exposure to pH2. Acidification did not modify the antigenic structure of IFN-γ as proved by a panel of mouse anti-human IFNγ antibodies.