Interferon gamma

Interferon gamma is distinct from interferon alpha and beta. It functions not so much as an antiviral, but as a signal between T-helper lymphocytes and mononuclear phagocytes.

It is a glycoprotein produced by:

• T-helper lymphocytes: by far the biggest source
• NK cells
• CD8+ cells
• mononuclear phagocytes

T-helper lymphocytes produce interferon gamma in response to interleukin-2 or antigen stimulation.

Its in vitro effects include:

• production of an antiviral state
• cytostatic for tumour cells
• activation of mononuclear phagocytes:
  • superoxide anion production
  • phagocytosis
  • MHC class II expression
  • intracellular killing
• activation of endothelial cells
• pyretic
• induction of acute phase response
• increased class I and II MHC expression in a range of cells

Clinically, it is currently used for the treatment of chronic granulomatous disease.