Interleukin-38

Interleukins (from Latin/Greek inter = between; leukos = white; kinein = to move) are a group of endogenous, short-chain regulatory proteins (cytokines) of the immune system (IL1-IL38). Interleukins are mediators for induction, course and control of T-cell-mediated cytotoxic immune reactions as well as B-cell activation (antibody production). They are mainly formed and secreted by stimulated leukocytes, monocytes and macrophages. So far, about 38 different interleukins have been clearly identified. Each cytokine of the interleukin group is nomenclatically assigned a number for its classification (IL-1 to IL-38 - status 2017).

Interleukin-38 is a cytokine of the interleukin-1 cytokine family discovered in 2001, to which the cytokines IL-1lalpha, IL-1beta, IL-1 receptor antagonist (IL-1Ra), IL-18, IL-36Ra, IL-36alpha, IL-37, IL-36βbeta, IL-36gamma and IL-33 belong.

The gene coding for IL-38, together with the IL-1 family cluster, is located on chromosome 2q13-14.1.

IL-38 shares structural properties with the IL-1 receptor antagonist (IL-1Ra) and IL-36Ra. IL-36R is the specific receptor of IL-38. IL-38 inhibits the production of the T-cell cytokines IL-17 and IL-22. IL-38 also inhibits the IL-36gamma-induced production of IL-8 and thus also an inflammatory response.

The members of the Interleukin-1 family play an important role in inflammatory processes and in primary immunological responses against invasive pathogenic microorganisms and physical damage.

IL-38 is an IL-36 antagonist. IL-38 reduces inflammatory reactions by antagonistic binding to the IL-36R receptor, which has been shown to be specific for IL-38.

IL-38 is mainly expressed in the skin and in proliferating B cells. In non-immunological tissues such as the heart and placenta, IL-38 is detectable, but only in low concentrations.

1. Hu Z et al (2015) Expression, purification of IL-38 in Escherichia coli and production of polyclonal antibodies. Protein Expr Purif 107:76-82.
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4. Wang HJ et al (2016) Elevated serum interleukin-38 level at baseline predicts virological response in telbivudine-treated patients with chronic hepatitis B. World J Gastroenterol 22:4529-4537.
5. Yuan X et al(2015) Role of IL-38 and its related cytokines in inflammation. Mediators Inflammation:807976.