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 Violet 785
Brilliant™ Violet 785 (BV785) is a far-red-emitting tandem fluorophore that can be excited by the 405 nm Violet laser and collected using a 780/60 bandpass filter. BV785 has an excitation peak at 405 nm and an emission peak at 785 nm. BV785 exhibits a medium level of brightness and is most often used in flow cytometry. Older instruments may not be set up for a dye with such a large Stokes shift, however BV785 is especially well suited for spectral cytometers or sorters. This dye is part of the Brilliant™ Violet dye line of fluorescent polymers. Brilliant™ Violet 421 polymer is employed as the donor molecule in a series of tandem dyes with acceptor molecules emitting at various points across the visible light spectrum. The Brilliant™ Violet dyes are a superior alternative to QDot nanocrystals and similar to SuperNova dye from Beckman Coulter and StarBright dyes from Bio-Rad.