The HI111 monoclonal antibody specifically binds to CD11a, the 180 kDa integrin α chain. This type I transmembrane glycoprotein associates with CD18 (integrin β2) to form the heterodimeric glycoprotein CD11a/CD18. This heterodimer is also known as the lymphocyte (leukocytes) function associated antigen-1 (LFA-1) that is expressed on all leukocytes. LFA-1 is an adhesion molecule involved in lymphocyte and granulocyte functions. LFA-1 mediates adhesion of lymphoid cells to the vascular endothelium in association with its ligand, and the intracellular adhesion molecule-1 (ICAM-1), CD54. Other ligands are ICAM-2 (CD102) and ICAM-3 (CD50).
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.