The 4G2 monoclonal antibody specifically recognizes CD319 which is also known as CD2-like receptor activating cytotoxic cells (CRACC), Signaling lymphocytic activation molecule 7 (Slamf7), or novel Ly9. CD319 (CRACC) is a single-pass type I transmembrane glycoprotein that is encoded by Slamf7 (SLAM family member 7) which belongs to the SLAM family within the CD2-subset of the immunoglobulin superfamily (IgSF) of cell surface receptors. This receptor is comprised of an extracellular region with one N-terminal Ig-like V-type (IgV) domain followed by one Ig-like C2-type (IgC2) domain. Its cytoplasmic tail contains two immunoreceptor tyrosine-based switch motifs (ITSMs). This receptor is variably expressed on activated CD4+ T cells and CD8+ T cells, NKT cells, NK cells, B cells, monocytes, macrophages, and dendritic cells. CD319 (CRACC) serves as a homotypic adhesion molecule that can self-associate and trigger cellular activation, such as cell-mediated cytotoxicity, when its cytoplasmic domains are associated with adaptor molecules including EWS-activated transcript 2 (EAT-2) and possibly EAT-2-related transducer (ERT). In cells that lack EAT-2, CD319 (CRACC) may exhibit an inhibitory function.
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.