The MAC2-158 monoclonal antibody (also known as Clone MAC 2-158) specifically binds to human CD163. CD163 is also known as Scavenger receptor cysteine-rich type 1 protein M130 (M130), SCARI1 (SR-I1), or Hemoglobin scavenger receptor (HbSR). CD163 is an ~130 kDa type I transmembrane glycoprotein comprised of an extracellular domain with nine cysteine-rich (SRCR) scavenger receptor class B domains followed by a transmembrane region and a short cytoplasmic tail. CD163 is expressed on most peripheral blood monocytes, tissue macrophages, and a subset of dendritic cells. CD163 serves as a high affinity receptor for hemoglobin and haptoglobin and mediates endocytosis of hemoglobin and haptoglobin complexes by macrophages. This scavenging function may protect tissues from hemoglobin-mediated oxidative damage and contribute to the uptake and recycling of iron. CD163 can also reportedly bind to (TNF-a)-like weak inducer of the apoptosis (TWEAK) protein and some pathogenic bacteria. A cleaved, soluble form of CD163 can reportedly play an anti-inflammatory role and serve as a marker for macrophage activation in inflammatory responses. High-affinity binding of the MAC2-158 antibody to CD163 is reportedly unaffected by extracellular calcium levels. This clone can be used to measure CD163 expression in freshly drawn whole blood samples stabilized with commonly used anticoagulants, eg, EDTA, citrate or heparin.
The antibody was conjugated to BD Horizon™ BV711 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 711-nm. BD Horizon BV711 can be excited by the violet laser and detected in a filter used to detect Cy™5.5 / Alexa Fluor™ 700-like dyes (eg, 712/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there may be moderate spillover into the Alexa Fluor™ 700 and PerCP-Cy5.5 detectors. However, the spillover can be corrected through compensation as with any other dye combination.