Interleukin 13

Interleukin 13 (IL-13) is a protein that in humans is encoded by the IL13 gene. IL-13 is an interleukin produced by T cells as an immunoregulatory cytokine following their activation by antigens. This interleukin is a key mediator in the pathogenesis of allergic inflammation and associated airway hyperresponsiveness, making it a central player in conditions such as asthma and allergic rhinitis.

Structure and Function

IL-13 is a monomeric protein, approximately 13 kDa in size, and is composed of four alpha-helical bundles. It shares many structural and functional characteristics with IL-4, due to their close proximity on chromosome 5 and their shared receptor component.

IL-13 exerts its effects through a multi-subunit receptor that includes the alpha chain of the IL-4 receptor (IL-4Rα) and the IL-13 receptor alpha 1 (IL-13Rα1). This receptor complex also engages with the Janus kinase (JAK) family of tyrosine kinases and the STAT family of transcription factors, specifically STAT6.

Role in Disease

IL-13 is implicated in a number of inflammatory diseases. In asthma, IL-13 is known to induce goblet cell metaplasia, subepithelial fibrosis, smooth muscle hyperplasia, and eotaxin production, leading to airway hyperreactivity. It is also involved in the pathogenesis of allergic rhinitis and atopic dermatitis.

In addition, IL-13 has been identified as a central mediator in fibrosis, contributing to diseases such as pulmonary fibrosis and liver cirrhosis.

Therapeutic Target

Given its role in various diseases, IL-13 has become a target for therapeutic intervention. Several monoclonal antibodies, such as Lebrikizumab and Tralokinumab, have been developed to neutralize IL-13 and are currently in clinical trials for the treatment of asthma.

See Also

• Interleukin
• Cytokine
• Asthma
• Allergic rhinitis
• Atopic dermatitis
• Pulmonary fibrosis
• Liver cirrhosis