The L130 monoclonal antibody specifically binds to CD18 which is also known as β2 integrin. CD18 is an ~90-95 kDa type I transmembrane glycoprotein that is encoded by ITGB2. CD18 associates with the integrin α chains CD11a, CD11b, CD11c, or CD11d to form the LFA-1, Mac-1, p150,95, or αDβ2 heterodimers, respectively. CD18 is expressed on virtually all normal peripheral blood leucocytes. CD18 serves as a leucocyte adhesion receptor and signaling receptor. It is essential for many immune responses that require cell-to-cell contact, such as lymphocyte adhesion, natural killer (NK) cell and T-lymphocyte cytolysis, and T lymphocyte proliferation.
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.