Interleukin 19


Interleukin 19 is a protein that in humans is encoded by the IL19 gene on the chromosome 1.

Structure

The IL-19 gene contains 7 exons and is found on chromosome 1. Secreted IL-19 is made from 159 amino acids that create alpha-helix structure.

Function

The protein encoded by this gene is a cytokine that belongs to the IL-10 cytokine subfamily. This cytokine is found to be preferentially expressed in monocytes and less in B lymphocytes. The IL-19 gene is expressed in resting monocytes and B cells. It is up-regulated in monocytes following stimulation with granulocyte-macrophage colony-stimulating factor, lipopolysaccharide, or Pam3CSK4.

Immunoregulation function

IL-19 increases the production of Th2 cytokines in T-lymphocytes and induces expression of IL-10 in monocytes.
Disorder of the IL-19 production probably has an effect to different allergic reactions and other Th1 type athopic and skis pathogeneses, e.g. psoriasis.
IL-19 also forms homologs with IL-20 and IL-24 and thus is able to bind the interleukin-20 receptor complex and lead to the activation of the signal transducer and activator of transcription 3. STAT3 is necessary for embryonal development and Th17 differentiation. The IL-20 receptors are predominantly found in the mesenchymal region of tissues, lungs and reproduction organs.
A similar cytokine in mouse is reported to up-regulate the expression of IL6 and TNF-alpha and induce apoptosis, which suggests a role of this cytokine in inflammatory responses. Alternatively spliced transcript variants encoding the distinct isoforms have been described.

IL-10 family

Interleukin-19 is a cytokine that belongs to the IL-10 family of cytokines along with several other interleukins including IL-10, IL-20, IL-22, IL-24, IL-26, and several virus-encoded cytokines. It signals through the same cell surface receptor that is used by IL-20 and IL-24.