The LY9.7.144 monoclonal antibody specifically recognizes CD229 which is also known as SLAM family member 3 (SLAMF3), Lymphocyte antigen 9 (Ly-9), Lgp100, and T100. CD229 is a ~90-120 kDa type I transmembrane glycoprotein that is encoded by Ly9 (lymphocyte antigen 9) which belongs to the Signaling Lymphocytic Activation Molecule (SLAM) family within the immunoglobulin gene superfamily. The extracellular domain of CD229 contains four extracellular Ig-like domains (2 V-set and 2 C-set) extending in order from the N-terminus as V-C2-V-C2. The intracellular region of CD229 contains two ITSMs (immunoreceptor tyrosine-based switch motifs) and serves as a docking site for SH2-binding phosphatases and adapter molecules including SAP and EAT-2. CD229 is variably expressed on most thymocytes, T cells, NKT cells, B cells, NK cells, hematopoietic stem cells and progenitor cells, and monocytes. CD229 participates in homophilic adhesion interactions between these cells and in the regulation of their activation.
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.