The WM53 monoclonal antibody specifically recognizes CD33 which is also known as Sialic acid-binding Ig-like lectin 3 (Siglec-3) or gp67. CD33 is a 67 kDa type I transmembrane glycoprotein that is variably expressed on myeloid progenitors, monocytes, macrophages, dendritic cells, neutrophils, basophils, mast cells, and on some activated T cells and NK cells. Normal lymphocytes, platelets, erythrocytes and pluripotent hematopoietic stem cells do not express the CD33 antigen. This glycoprotein reportedly functions as a sialic acid-dependent cell adhesion molecule and this function can be modulated by endogenous sialoglycoconjugates when CD33 is expressed on the membrane.
The antibody was conjugated to BD Horizon BV786 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 786-nm. BD Horizon BV786 can be excited by the violet laser and detected in a filter used to detect Cy™7-like dyes (eg, 780/60-nm filter).