The V7.1 monoclonal antibody specifically recognizes CD101 which is also known as P126 or Glu-Trp-Ile EWI motif-containing protein 101 (EWI-101). CD101 is encoded by IGSF2 (Immunoglobulin superfamily member 2) and belongs to the EWI (sharing a conserved glutamine-tryptophan-isoleucine motif) family within the Ig superfamily. CD101 is a ~135-140 kDa type I transmembrane glycoprotein that has a short cytoplasmic domain with potential phosphorylation sites and an extracellular region with seven immunoglobulin-variable (IgV)-like domains. CD101 is expressed as homodimers by granulocytes, monocytes, dendritic cells, and some T cells. Its expression by T cells may be upregulated upon activation through the CD3 complex. CD101 may play a role in TCR/CD3-dependent T-cell activation.
The antibody was conjugated to BD Horizon™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.