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 BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).