The 421203 monoclonal antibody specifically recognizes Claudin-1 which is also known as Senescence-associated epithelial membrane protein 1 (SEMP1) or Ichthyosis, leukocyte vacuoles, alopecia, and sclerosing cholangitis (ILVASC). Claudin-1 is a ~23 kDa multi-pass membrane protein that is encoded by CLDN1 (claudin 1) which belongs to the claudin family. Claudin-1 is expressed by Langerhans cells, dendritic cells, epithelial cells and endothelial cells. It serves as a major component of tight junctions between epithelial or endothelial cells. Claudin-1 may also function as a co-receptor for Hepatitis C virus (HCV) entry into hepatic cells. Dysregulated Claudin-1 expression has been detected in multiple types of cancer.
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.