The U29-93 monoclonal antibody specifically binds to the mouse Interleukin-33 Receptor (IL-33 Receptor, or IL-33R) which is also known as ST2. The IL-33R exists in either a type I transmembrane or soluble glycoprotein form. These IL-33R forms are encoded by the Il1rl1 (Interleukin-1 receptor-like 1) gene which belongs to the IL-1 Receptor family within the Ig superfamily. The IL-33R is expressed by subsets of T cells, including Th2-like cells and some regulatory T cells, as well as some innate lymphocytes, eosinophils, basophils, and mast cells. The IL-33R (also known as the IL-33R alpha subunit, or IL-33Rα) binds IL-33 and complexes with the IL-1R Accessory Protein (IL1RAP) to form a functional signaling receptor complex that can induce the production of T helper type 2 (Th2) cytokines. The soluble IL-33R may function as a decoy receptor which can block the binding of IL-33 to the transmembrane IL-33R. The IL-33R plays roles in inflammation, immunity, and allergy.
The antibody was conjugated to BD Horizon™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.