About CD19
This gene encodes a member of the immunoglobulin gene superfamily. Expression of this cell surface protein is restricted to B cell lymphocytes. This protein is a reliable marker for pre-B cells but its expression diminishes during terminal B cell differentiation in antibody secreting plasma cells. The protein has two N-terminal extracellular Ig-like domains separated by a non-Ig-like domain, a hydrophobic transmembrane domain, and a large C-terminal cytoplasmic domain. This protein forms a complex with several membrane proteins including complement receptor type 2 (CD21) and tetraspanin (CD81) and this complex reduces the threshold for antigen-initiated B cell activation. Activation of this B-cell antigen receptor complex activates the phosphatidylinositol 3-kinase signalling pathway and the subsequent release of intracellular stores of calcium ions. This protein is a target of chimeric antigen receptor (CAR) T-cells used in the treatment of lymphoblastic leukemia. Mutations in this gene are associated with the disease common variable immunodeficiency 3 (CVID3) which results in a failure of B-cell differentiation and impaired secretion of immunoglobulins. CVID3 is characterized by hypogammaglobulinemia, an inability to mount an antibody response to antigen, and recurrent bacterial infections. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Jul 2020]

About Brilliant Ultraviolet 395
Brilliant™ UltraViolet 395 (BUV395) is a UV-emitting base polymer dye that can be excited by the 355 nm ultraViolet laser and collected using a 379/28 bandpass filter. BUV395 has an excitation peak at 348 nm and an emission peak at 395. BUV395's fairly unique excitation and emission spectrum causes relatively little spillover into other common detectors and conflicts with very few other commonly used fluorophores. An alternative to BUV395 for flow cytometry is StarBright UltraViolet 400. This dye is part of the Brilliant™ UltraViolet dye family, developed and sold by BD Biosciences. These dyes were optimized for use with multicolor flow cytometry. BUV395 forms the backbone of the family, as all other members are tandems that use it as the acceptor, thus making them excitable by the same 355 nm UV laser.