The RPA-2.10 monoclonal antibody specifically binds to CD2 which is also known as Lymphocyte-function antigen-2 (LFA-2), LFA-3 receptor, Erythrocyte receptor, Sheep red blood cell (SRBC) receptor, or T-cell surface antigen T11/Leu-5. CD2 is a 50 kDa type I transmembrane glycoprotein. CD2 belongs to the immunoglobulin superfamily of proteins along with its primary ligand, LFA-3 (CD58). It is expressed on the surface of ~80-90% of human peripheral blood lymphocytes, greater than 95% of thymocytes, all T lymphocytes that form E-rosettes, and a subset of NK cells. CD2 functions as an adhesion receptor that binds to CD58 resulting in the activation of CD2-positive T cells and NK cells and in the regulation of their cytolytic activities.
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.