Interleukin 4

Interleukin 4

Structure of Interleukin 4

Interleukin 4 (IL-4) is a cytokine that plays a crucial role in the immune system. It is primarily produced by activated T cells, specifically T helper 2 cells, as well as by mast cells, basophils, and eosinophils. IL-4 is a key regulator in humoral immunity and is involved in the differentiation of naive T helper cells (Th0 cells) into Th2 cells.

Function

IL-4 is essential for the class switching of B cells to produce IgE and IgG1 antibodies. It also promotes the growth and differentiation of B cells and T cells. IL-4 acts as a growth factor for B cells and T cells, and it enhances the expression of MHC class II molecules on antigen-presenting cells.

Mechanism of Action

IL-4 exerts its effects by binding to the interleukin 4 receptor (IL-4R), which is expressed on the surface of various immune cells. The IL-4 receptor is a type I cytokine receptor that consists of the IL-4R_ chain and the common gamma chain (_c). Upon binding to its receptor, IL-4 activates the JAK-STAT signaling pathway, leading to the transcription of specific genes involved in immune response regulation.

Role in Disease

IL-4 is implicated in the pathogenesis of allergic diseases such as asthma, allergic rhinitis, and atopic dermatitis. It is responsible for the IgE-mediated hypersensitivity reactions seen in these conditions. Elevated levels of IL-4 are often found in patients with these allergic disorders.

Therapeutic Target

Due to its role in allergic diseases, IL-4 is a target for therapeutic intervention. Monoclonal antibodies that inhibit IL-4 or its receptor are being developed and used to treat conditions like asthma and atopic dermatitis. These therapies aim to reduce the inflammatory response mediated by IL-4.

Related pages

• Cytokine
• T helper cell
• Immune system
• Allergy
• Asthma