The V46-1954 monoclonal antibody specifically recognizes mouse CD304, also known as neuropilin 1 (Nrp1). It does not cross-react with neuropilin 2 (Nrp2). CD304 is a type-1 transmembrane protein that plays important roles in neuronal development, angiogenesis, and immunosuppression. Through interactions with plexins and VEGF receptors on neurons and endothelial cells, it is a co-receptor for the class III semaphorin subfamily and vascular endothelial growth factor (VEGF), respectively. The ability of the S1 protein of SARS-CoV-2 virus to bind to Nrp1, a potential mechanism for cellular infection, is being investigated. In the immune system, CD304 is expressed on natural (thymus-derived) Treg cells and may be responsible for the unsuccessful immune regulation of tumor growth.
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.