The 2A9-1 monoclonal antibody specifically binds to human CX3CR1, which is also known as chemokine (C-C) receptor-like 1 (CCRL1), Beta chemokine receptor-like 1 (CMK-BRL-1), G protein-coupled receptor 13 (GPR13), or GPRV28 (V28). CX3CR1 is a seven transmembrane G protein coupled receptor that is expressed by NK cells, T cells, and monocytes. The cellular expression of CX3CR1 is correlated with high levels of intracellular perforin and granzyme B. CX3CR1 serves as a receptor for fractalkine (CX3CL1). Fractalkine is a transmembrane chemokine of the CX3C family that is expressed on activated endothelial cells, neurons, and astrocytes. Interaction of CX3CR1 with fractalkine initiates cellular adhesive and chemotactic responses.
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.