The U23-56 monoclonal antibody specifically binds to Macrophage scavenger receptor 1 (MSR1) which is also known as CD204, Scavenger receptor A (SRA), Scavenger receptor class A member 1 (SCARA1), or Macrophage acetylated LDL receptor I and II. MSR1 is a trimeric type II transmembrane glycoprotein that belongs to the type 1 class A scavenger receptor family. MSR1 functions as a scavenger receptor that enables mononuclear phagocytes to take up and respond to a variety of negatively charged macromolecules including oxidized and acetylated low density lipoproteins. MSR1 also functions in innate immunity as a pattern recognition receptor. MSR1 allows macrophages to recognize and respond to microbial products, such as lipopolysaccharide and polyribonucleic acids, by the production of cytokines and inflammatory mediators. MSR1 also reportedly serves as a coreceptor that regulates the signaling of some Toll-like receptors including TLR-3, TLR-4, and TLR-9. MSR1 has been associated with several diseases including atherosclerosis, Alzheimer's disease, ischemic injury, and sepsis. The U23-56 antibody was tested by flow cytometric and Western blot analyses of MSR1-transfected and untransfected cells to verify its specificity.
The antibody was conjugated to BD Horizon™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.