The P-3E10 monoclonal antibody specifically recognizes CD298, the β3 subunit of the Na+/K+ ATPase (Sodium/potassium-transporting ATPase subunit beta-3). CD298 is a ~45-55 kDa single-pass, type II membrane protein that is encoded by ATP1B3 (ATPase Na+/K+ transporting subunit beta 3) which belongs to the P-type ATPases superfamily. CD298 is widely expressed on lymphocytes, monocytes, granulocytes, platelets, and on other hematopoietic and nonhematopoietic cells and cell lines. The Na+/K+ ATPase is an integral membrane protein complex with enzymatic activity that mediates the active transport and exchange of sodium and potassium ions across the plasma membrane. This complex is composed of α and β subunits. The α subunit is a 10-membrane-spanning, catalytic protein that contains binding sites for Na +, K + and ATP. The α subunits are associated with the smaller, regulatory glycoprotein β subunits. Upon ATP hydrolysis, the Na+/K+ ATPase transports Na+ ions out of the cell in exchange for K+ ions that are transported in. This establishes a transmembrane electrochemical gradient that is essential for osmoregulation and for the transport of various nutrients and other molecules by cells. The P-3E10 antibody can reportedly inhibit the activation and proliferation of T cells and B 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.