Interleukin 12

Interleukin 12 (IL-12) is a cytokine that is naturally produced by dendritic cells, macrophages, and human B-lymphocytes. It is involved in the differentiation of T cells and the production of interferon gamma (IFN-γ) by natural killer cells and T cells. IL-12 is a key regulator of cell-mediated immune response and plays a crucial role in the activities of natural killer cells and T lymphocytes.

Structure

IL-12 is a heterodimeric cytokine, composed of two subunits, IL-12p35 and IL-12p40, which are covalently linked. The IL-12p35 subunit is related to the p35 subunit of Interleukin 1 (IL-1), while the IL-12p40 subunit is related to the extracellular domain of the Interleukin 6 (IL-6) receptor.

Function

IL-12 is involved in the stimulation and maintenance of Th1 cellular immune responses, including the normal host defense against various intracellular pathogens, such as Mycobacterium tuberculosis. It promotes the development of Th1 cells from naive CD4+ T cells through the induction of the transcription factor T-bet, which further stimulates the production of IFN-γ.

Clinical significance

Due to its role in the immune response, IL-12 has been implicated in a number of diseases, including autoimmune diseases and cancer. In autoimmune diseases, such as multiple sclerosis and rheumatoid arthritis, IL-12 is thought to promote inflammation and tissue damage. In cancer, IL-12 has shown promise as a potential therapeutic agent due to its ability to stimulate an immune response against tumor cells.

See also

• Interleukin
• Cytokine
• T cells
• Interferon gamma