The MIH18 monoclonal antibody specifically binds to CD273 which is also known as the Programmed Death Ligand 2 (PD-L2) and B7-DC. CD273 is a type 1 transmembrane glycoprotein member of the B7 family and Ig superfamily. CD273 serves as a ligand for CD279, the Programmed Death 1 (PD-1) receptor. CD273 is expressed by dendritic cells, activated monocytes, medullary thymic epithelial cells, placental trophoblasts, and myocardial endothelium. CD273 can function as a coinhibitor of T cell functions by acting through CD279. Monoclonal antibodies that block the CD273 and CD279 interaction result in enhanced T cell proliferation and cytokine production. Thus, CD273 can play an important role in regulating T cell responses. Clone MIH18 is reportedly a blocking antibody.
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.