The C3 II.1 monoclonal antibody specifically recognizes CD49c which is also known as Integrin alpha 3 (α3 integrin). CD49c is encoded by ITGA3 (Integrin subunit alpha 3). CD49c is a 150 kDa type I transmembrane glycoprotein which non-covalently associates with integrin β1 (CD29) to form the α3β1 (CD49c/CD29, VLA-3) complex. CD49c is expressed mostly on endothelial and epithelial cells (basal epidermal layers). It is not expressed on platelets and is expressed weakly on peripheral blood leucocytes, including T cells, B cells, and monocytes. The CD49c/CD29 complex serves as an adhesive receptor for kalinin or epiligrin. This interaction may be important for thymocyte interaction with thymic epithelium.
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.