The S5.2 monoclonal antibody specifically recognizes the CD2 antigen, a 45 to 50 kDa type I transmembrane glycoprotein that forms the binding site for sheep erythrocytes. The CD2 antigen is present on approximately 75% of normal peripheral blood lymphocytes and 95% to 99% of thymocytes. It is also found on a subset of monocytes (approximately one-third) that might be precursors to dendritic cells. The CD2 antibody reacts with essentially all T lymphocytes and with a subset of NK lymphocytes. CD2 and CD58 have been shown to be coreceptors. The interaction of CD2 antigen and CD58 antigen facilitates antigen recognition by T lymphocytes.
The antibody was conjugated to BD Horizon™ BV421 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max at 421-nm, BD Horizon BV421 can be excited by the violet laser and detected in the standard Pacific Blue™ filter set (eg, 450/50-nm filter). BD Horizon BV421 conjugates are very bright, often exhibiting a 10 fold improvement in brightness compared to Pacific Blue conjugates.