Interleukin-19 is a cytokine

Cytokine

Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...

 that belongs to the IL-10

Interleukin 10

Interleukin-10 , also known as human cytokine synthesis inhibitory factor , is an anti-inflammatory cytokine. In humans IL-10 is encoded by the IL10 gene....

 family of cytokines along with several other interleukin

Interleukin

Interleukins are a group of cytokines that were first seen to be expressed by white blood cells . The term interleukin derives from "as a means of communication", and "deriving from the fact that many of these proteins are produced by leukocytes and act on leukocytes"...

s including IL-10

Interleukin 10

Interleukin-10 , also known as human cytokine synthesis inhibitory factor , is an anti-inflammatory cytokine. In humans IL-10 is encoded by the IL10 gene....

, IL-20

Interleukin 20

Interleukin-20 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-22

Interleukin 22

Interleukin-22 is protein that in humans is encoded by the IL22 gene.IL-22 a member of a group of cytokines called the IL-10 family or IL-10 superfamily , a class of potent mediators of cellular inflammatory responses. It shares use of IL-10R2 in cell signaling with other members of this family,...

, IL-24

Interleukin 24

Interleukin 24 is a cytokine belonging to the IL-10 family of cytokines that signals through two heterodimeric receptors: IL-20R1/IL-20R2 and IL-22R1/IL-20R2. This interleukin is also known as Melanoma differentiation-associated 7 due to its discovery as a tumour suppressing protein...

, IL-26

Interleukin 26

Interleukin-26 is a protein that in humans is encoded by the IL26 gene.IL-26 is a 171-amino acid protein, which is similar in amino acid sequence to interleukin 10. It was originally called AK155 and is composed of a signal sequence, 6 helices, and 4 conserved cysteine residues...

, and several virus

Virus

A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

-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

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 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

Lipopolysaccharide

Lipopolysaccharides , also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals.-Functions:LPS is the major...

.