The HIM3-4 monoclonal antibody specifically binds to CD33 which is also known as Sialic acid-binding Ig-like lectin 3 (Siglec-3), gp67, or p67. CD33 is a 67 kDa type I transmembrane glycoprotein expressed on monocytes, activated T cells, myeloid progenitors as well as mast cells. CD33 is absent on normal platelets, lymphocytes, erythrocytes and hematopoietic stem cells. This glycoprotein can reportedly function as a sialic acid-dependent cell adhesion molecule. This function can be modulated by endogenous sialoglycoconjugates when CD33 is expressed on the membrane. HIM3-4 reacts with human and monkey granulocytes and monocytes.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).