INF-γ

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

Structure and Function

INF-γ 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 antigenic or mitogenic stimuli. The gene encoding INF-γ is located on chromosome 12 in humans.

Role in Immune Response

INF-γ plays a key role in the immune response by:

• Activating macrophages to enhance their microbicidal activity.
• Increasing the antigen presentation by dendritic cells and macrophages through upregulation of MHC class I and II molecules.
• Promoting the differentiation of naive T cells into Th1 cells.
• Inhibiting the proliferation of Th2 cells and Th17 cells.

Clinical Significance

INF-γ has been implicated in the pathogenesis of several diseases:

• Autoimmune diseases: Overproduction of INF-γ can contribute to the development of autoimmune diseases such as multiple sclerosis, type 1 diabetes, and rheumatoid arthritis.
• Infectious diseases: Deficiency in INF-γ production or response can lead to increased susceptibility to infections, particularly those caused by intracellular pathogens like Mycobacterium tuberculosis.
• Cancer: INF-γ has both tumor-promoting and tumor-inhibiting effects, depending on the context of the tumor microenvironment.

Therapeutic Use

Recombinant INF-γ is used as a therapeutic agent in certain conditions, including:

• Chronic granulomatous disease: To reduce the frequency and severity of infections.
• Osteopetrosis: To improve bone resorption and immune function.

Related Pages

• Cytokine
• Macrophage
• Major histocompatibility complex
• Natural killer cell
• T lymphocyte
• Autoimmune disease
• Multiple sclerosis
• Type 1 diabetes
• Rheumatoid arthritis
• Mycobacterium tuberculosis
• Chronic granulomatous disease
• Osteopetrosis