IL-33 is also a member of the IL-1 family; however it differs from IL-1β in its activation control mechanism. Like IL-1α, IL-33 is present in the nucleus under normal conditions. Although the function of IL-33 as a nuclear factor remains elusive, its binding to the nucleosomal surface to suppress transcription has been demonstrated by in vitro experiments.

IL-33 is expressed in a variety of cells (including endothelial, epithelial, and fat cells) and tissues (such as the stomach, lungs, skin, lymph nodes, and kidneys). Its up-regulated expression is reported in the mouse brain and spinal cord. IL-33 is has been implicated in diseases ranging from parasitic infection and allergic diseases to arthritis, diabetes, inflammatory bowel disease, SLE, and Alzheimer’s disease.


Specific IL-33 Involvement:

Full-length IL-33 is released extracellularly and activates the immune cells expressing IL-33 receptors. At the inflammation site, IL-33 undergoes limited proteolysis by the proteases released from neutrophils and other cells, and limited proteolysis results in its enhanced activity.

IL-33 is cleaved by activated caspase-3 and caspase-7, which terminates its inflammation-inducing ability.

Full-length IL-33 released extraceullarly acts on diverse leucocytes to induce production of primarily Th2-type cytokines and plays a role mainly in defense mechanisms against parasite infection. A team from Keio University discovered the presence in the mouse visceral fat tissues of natural helper (NH) cells that secrete a large amount of Th2-type cytokines through IL-33 action. This has become a hot topic because the part of the system that provides protection from parasite infection has been elucidated.

Excellent IHC

Ideal for Western Blotting


Functional Grade IL-33 Antibodies Available

Code No.Species ReactivitiesApplicationsClonalityNotes
M187-3   MouseWB, NTMonoclonalFunctional Grade
M188-3MouseWB, NTMonoclonalFunctional Grade


  1. Liew FY, Pitman NI, Nat. Rev. Immunol., 10, 103-10 (2010), PMID: 20081870
  2. Moro K, Yamada T, et al.,Nature 463, 540-4 (2010), PMID: 2002630
  3. Oboki K, Ohno T, et al., Allergol. Int., 59, 143-60 (2010) PMID: 20414050

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