Rabbit Anti-Human IL-33 monoclonal antibody for WB. Interleukin 33 belongs to the IL-1 family of cytokines having dual mode of activity either as being secreted from cells to elicit their effects in an autocrine and paracrine manner or in an intracrine, nonsecreted manner as nuclear factors. IL-33 is produced by various tissue dwelling cells and is a crucial cytokine for Th2 cytokine-mediated host defense as well as induction of Th2-type allergic disorders. IL-33 has an additional role inside the cell, accumulating in the nucleus and associating with heterochromatin and mitotic chromatin and functioning as a transcriptional-repressor activity.