The D12 monoclonal antibody specifically binds to CD11b which is also known as Integrin alpha M (Integrin αM), Mac-1 subunit alpha (Mac-1a) or complement receptor 3 alpha chain (CR3a). CD11b is encoded by ITGAM (integrin subunit alpha M) and belongs to the integrin alpha subunit gene family. CD11b is expressed as a ~165-kDa type I transmembrane glycoprotein that associates with the ~95-kDa integrin β2 (CD18) to form the heterodimeric CD11b/CD18 (αM/β2) complex which also known as Mac-1 or CR3. CD11b is expressed on monocytes, dendritic cells, granulocytes, as well as on some T cells, B cells, and NK cells. CD11b functions in cell-cell and cell-substrate interactions and is a receptor for multiple ligands including inactivated C3b (iC3b), ICAM-1 (CD54), ICAM-2 (CD102), ICAM-3 (CD50) or fibrinogen. Mac-1 regulates leucocyte adhesion and migration, as well as phagocytosis of opsonized particles.
CAUTION Binding of this CD11b antibody depends on the presence of Ca++. EDTA or ACD, as anticoagulant might affect binding. Using heparin as an anticoagulant or removal of the anticoagulant is recommended.
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).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.