The NP4D6 monoclonal antibody specifically binds to CD203c. CD203c is a type II transmembrane glycoprotein that is a member of the E-NNP family of ectoenzymes. CD203c is also known as ectonucleotide pyrophosphatase/phosphodiesterase 3 (E-NPP3, ENPP3) due to its capacity to hydrolyze phosphodiester and phosphosulfate bonds in a variety of molecules including deoxynucleotides, nucleoside phosphates, and nicotinamide adenine dinucleotide. CD203c is otherwise known as Phosphodiesterase-1β (PD-1β, PD-I beta), B10, or gp130RB13-6. CD203c is expressed by basophils and mast cells. Basophils increase CD203c expression following activation with allergens or antibodies that crosslink cytophilic IgE. Thus, CD203c serves as a useful flow cytometric marker for basophil activation and the detection and analysis of type 1 allergic responses. IgE-receptor cross-linking results in CD203c upregulation and overexpression on neoplastic mast cells in cases of systemic mastocytosis.
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).