The 159227 monoclonal antibody specifically recognizes MHC class I polypeptide-related sequence A (MICA) which is also known as MIC-A, MHC class I chain-related protein A, or stress inducible class I homolog. This ~70 kDa single-pass type I transmembrane glycoprotein is encoded by MICA (major histocompatibility complex class I chain-related gene A) which is a highly polymorphic gene. MICA is very homologous to another protein, MICB. Both MICA and MICB are homologous to major histocompatibility complex (MHC) class I molecules although they lack association with β2 microglobulin. MICA and MICB each contain three extracellular Ig domains but have no capacity to bind peptides. MICA is expressed on some gut epithelial cells. Its expression by other epithelial cells and cell types, including fibroblasts and endothelial cells, is induced by stress, eg, stress caused by bacterial and viral infections, autoimmunity, transplantation rejection, or cellular transformation. MICA and MICB are ligands for NKG2D (CD314), an activating receptor expressed by natural killer (NK) cells, γδ T cells, CD8+ αβ T cells, and some CD4+ αβ T cells.
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.