IGF1

Interferon gamma (IFNγ) is a cytokine that is critical for innate and adaptive immunity against viral and intracellular bacterial infections and for tumor control. It is an important activator of macrophages and inducer of major histocompatibility complex (MHC) class II molecule expression. Aberrant IFNγ expression is associated with a number of autoinflammatory and autoimmune diseases.

Structure and Function

IFNγ is a dimerized soluble cytokine that is the only member of the type II class of interferons. It is produced predominantly by natural killer cells and T lymphocytes in response to recognition of infected or transformed cells. The gene encoding IFNγ is located on chromosome 12 in humans.

The primary function of IFNγ is to activate macrophages and enhance their ability to kill intracellular pathogens. It also increases the antigen presentation capacity of antigen-presenting cells by upregulating the expression of MHC class I and II molecules. This enhances the immune system's ability to recognize and respond to infected or malignant cells.

Role in Immune Response

IFNγ plays a pivotal role in both the innate and adaptive immune responses. In the innate immune response, IFNγ is produced by natural killer cells and acts to activate macrophages, enhancing their microbicidal activity. In the adaptive immune response, IFNγ is produced by T helper 1 cells (Th1) and cytotoxic T lymphocytes (CTLs), promoting the differentiation of naive T cells into Th1 cells and enhancing the cytotoxic activity of CTLs.

Clinical Significance

Dysregulation of IFNγ production or signaling can lead to a variety of diseases. Overproduction of IFNγ is associated with autoinflammatory and autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis. Conversely, insufficient IFNγ production can lead to increased susceptibility to infections, particularly those caused by intracellular pathogens such as Mycobacterium tuberculosis.

Therapeutic Applications

Recombinant IFNγ is used as a therapeutic agent in certain conditions. It is approved for the treatment of chronic granulomatous disease and severe, malignant osteopetrosis. Research is ongoing to explore its potential use in cancer immunotherapy and as an adjuvant in vaccines.

Also see

• Cytokine
• Interferon
• Macrophage
• T lymphocyte
• Major histocompatibility complex