Interleukin-12 Subunit p40

Interleukin-12 subunit p40 (IL-12p40) is also known as IL-12B, natural killer cell stimulatory factor 2, and cytotoxic lymphocyte maturation factor p40. IL-12p40 is a subunit of IL-12p70 and IL-23. It can exist as a monomer or homodimer (IL-12p80) and can function as a negative feedback loop by competitively binding to the IL-12 receptor. Produced primarily by macrophages, neutrophils, microglia, and dendritic cells, IL-12p40 induces and activates T helper-1 cells in cooperation with IL-12p70. It also promotes the induction and activation of T helper-17 cells in cooperation with IL-23. IL-12p40 is a chemoattractant for macrophages and induces dendritic cells stimulated by bacteria to migrate. IL-12p40 is associated with inflammatory responses including silicosis, graft rejection, asthma, and juvenile idiopathic arthritis. Serum levels of IL-12p40 are significantly higher in patients with active tuberculosis and latent tuberculosis compared to patients without tuberculosis. IL-12p80 have been detected in bronchoalveolar lavage of asthmatic patients. Blocking IL-12p40 has been shown to be efficacious in treating Inflammatory Bowel Diseases such as Crohn?s Disease and ulcerative colitis by repressing T helper-1 cell type immune responses. IL-12p40 is an attractive target since it can affect activities of both IL-12p70 and IL-23.

Swiss-Prot Accession Number: P29460