It 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 (IL-20R) that is used by IL-20 and IL-24. 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 (GM-CSF) or lipopolysaccharide.
Interleukin-20 (IL-20) it is a protein belonging to the IL-10 family of cytokines. IL-20 is produced by activated keratinocytes and monocytes and transmits an intracellular signal through two distinct cell-surface receptor complexes on keratinocytes and other epithelial cells.
IL-20 regulates proliferation and differentiation of keratinocytes during inflammation, particularly inflammation associated with the skin. In addition, IL-20 also causes cell expansion of multipotential hematopoietic progenitor cells.
Other groups of cytokines include interferons and chemokines. Interferons inhibit virus replication in infected cells and stimulate MHC expression of antigen- presenting cell also. Chemokines attract leukocytes to infection sites.