The MD22 monoclonal antibody specifically recognizes CD64 which is also known as Fc-gamma receptor I (FcgR1) or FcγRI. CD64 is a ~72 kDa type I transmembrane glycoprotein that is encoded by FCGR1A (Fc fragment of IgG receptor Ia). CD64 functions as a high affinity receptor for human IgG. The CD64 antigen is expressed on monocytes, macrophages, at low levels on polymorphonuclear neutrophils (PMNs), and on a subpopulation of circulating dendritic cells. The CD64 antigen is an early granulomonocytic lineage marker on CD34+ hematopoietic progenitors. Expression of the CD64 antigen increases transiently in cases of sepsis. The CD64 antigen functions in both innate and adaptive immune responses, and mediates endocytosis, phagocytosis, antigen presentation, antibody-dependent cellular cytotoxicity, cytokine release, and superoxide generation. The CD64 antigen associates with the signal-transducing γ-chain homodimer of Fc receptors to form the functional high affinity FcγRI complex. Ligation of the CD64 antigen leads to the activation of the protein tyrosine kinases, hck and lyn.
This antibody is conjugated to BD Horizon™ BV605 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max of 602-nm, BD Horizon BV605 can be excited by a violet laser and detected with a standard 610/20-nm filter set. BD Horizon BV605 is a tandem fluorochrome of BD Horizon BV421 and an acceptor dye with an Em max at 605-nm. Due to the excitation of the acceptor dye by the green (532 nm) and yellow-green (561 nm) lasers, there will be significant spillover into the PE and BD Horizon PE-CF594 detectors off the green or yellow-green lasers. BD Horizon BV605 conjugates are very bright, often exhibiting brightness equivalent to PE conjugates and can be used as a third color off of the violet laser.