Interleukin 17

Interleukin 17 (IL-17), also known as IL-17A, is a pro-inflammatory cytokine that plays a crucial role in host defense mechanisms and inflammatory diseases. It is produced by a subset of T cells known as Th17 cells, which are part of the adaptive immune system.

Function

IL-17 has a wide range of functions in the immune system. It is primarily involved in the defense against extracellular bacteria and fungi by inducing the production of other cytokines, chemokines, and antimicrobial peptides. This leads to the recruitment and activation of neutrophils, which are essential for the clearance of these pathogens.

In addition to its role in host defense, IL-17 is also implicated in the pathogenesis of various inflammatory and autoimmune diseases, including rheumatoid arthritis, psoriasis, and multiple sclerosis. It promotes inflammation by inducing the production of pro-inflammatory cytokines and chemokines, leading to the recruitment and activation of immune cells.

Structure

IL-17 is a homodimeric protein composed of two identical subunits. Each subunit consists of a single polypeptide chain that is folded into a unique cysteine-knot structure. This structure is shared by all members of the IL-17 family, which includes six cytokines (IL-17A to IL-17F).

Clinical significance

Due to its role in inflammation and autoimmune diseases, IL-17 has become a target for therapeutic intervention. Several drugs that inhibit the activity of IL-17 or block its receptor have been developed and approved for the treatment of psoriasis, psoriatic arthritis, and ankylosing spondylitis. These drugs have shown efficacy in reducing the symptoms of these diseases, but they can also have side effects, including an increased risk of infections.

See also

• Interleukin
• Cytokine
• T cell
• Neutrophil
• Rheumatoid arthritis
• Psoriasis
• Multiple sclerosis