The C9Mab-1 monoclonal antibody specifically binds to Chemokine (C-C motif) receptor 9 (CCR9), which is also known as CD199. CCR9 is an ~42 kDa seven-transmembrane protein in the G protein-coupled receptor (GPCR) supergene family. It is upregulated by CD4+CD8+ double-positive thymocytes, then downregulated in committed CD4+ or CD8+ single-positive thymocytes. CCR9 is also expressed on small intestinal B cells, subsets of memory CD4+ T cells and CD8+ T cells, and dendritic cells. CCR9 binds CCL25, which is also known as thymus-expressed chemokine (TECK) or small inducible chemokine 25 (Scya25). CCL25 is highly expressed in the thymic cortex and small intestinal epithelium. CCR9 is involved in T cell development and gut-associated immune functions via lymphocyte recruitment to the gastrointestinal tract.
The antibody was conjugated to BD Horizon BV750 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 750-nm. BD Horizon Brilliant BV750 can be excited by the violet laser (405 nm) and detected with a 750/30 nm filter with a 740 nm long pass. Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BV750 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended.