Miltenyi, 130-133-519, Human IL-37b, research grade

Biological activity

Background information
Interleukin 37b (IL-37b/IL-1F7) is a member of the IL-1 cytokine family and is expressed by various immune and non-immune cell types, including monocytes, macrophages, DCs, B cells, and epithelial cells. IL-37b is the largest and most abundant of five IL-37 isoforms (IL-37a to e), each showing a distinct tissue expression profile. The recombinant protein corresponds to mature IL-37b (aa 46-218).
IL-37 has been described as an anti-inflammatory and immunomodulatory cytokine with intracellular and extracellular functions. It is synthesized and released into the cytosol in an inactive form that contains a caspase 1 cleavage site. Maturation and Golgi/ER-independent secretion are regulated by inflammasome activation. Mature, intracellular IL-37 can bind to Smad3 and translocate to the nucleus to inhibit the expression of pro-inflammatory cytokines. Secreted IL-37 can interact with the IL-18 receptor and IL-1R8, albeit with low affinity. It can also bind to the IL-18 binding protein (IL-18BP), thereby enhancing antagonization of IL-18 activity.
With regard to its immunomodulatory function, several autoimmune diseases have been associated with elevated serum levels of IL-37, including rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, multiple sclerosis, and Sjögren’s syndrome. However, the exact mechanisms through which IL-37 is involved in autoimmune diseases remain incompletely understood.

Overview
IL-37b stands for interleukin 37 beta. Human IL-37b is a recombinant protein optimized for use in cell culture and functional assays.