About IgM
Immunoglobulins (Ig) are the antigen recognition molecules of B cells. An Ig molecule is made up of 2 identical heavy chains and 2 identical light chains (see MIM 147200) joined by disulfide bonds so that each heavy chain is linked to a light chain and the 2 heavy chains are linked together. Each Ig heavy chain has an N-terminal variable (V) region containing the antigen-binding site and a C-terminal constant (C) region, encoded by an individual C region gene, that determines the isotype of the antibody and provides effector or signaling functions. The heavy chain V region is encoded by 1 each of 3 types of genes: V genes (see MIM 147070), joining (J) genes (see MIM 147010), and diversity (D) genes (see MIM 146910). The C region genes are clustered downstream of the V region genes within the heavy chain locus on chromosome 14. The IGHM gene encodes the C region of the mu heavy chain, which defines the IgM isotype. Naive B cells express the transmembrane forms of IgM and IgD (see IGHD; MIM 1471770) on their surface. During an antibody response, activated B cells can switch to the expression of individual downstream heavy chain C region genes by a process of somatic recombination known as isotype switching. In addition, secreted Ig forms that act as antibodies can be produced by alternative RNA processing of the heavy chain C region sequences. Although the membrane forms of all Ig isotypes are monomeric, secreted IgM forms pentamers, and occasionally hexamers, in plasma (summary by Janeway et al., 2005).[supplied by OMIM, Aug 2010]

About Brilliant Violet 480
Brilliant™ Violet 480 (BV480) is a green-emitting non-tandem polymer fluorophore that can be excited by the 405 nm Violet laser and collected using a 525/40 bandpass filter. BV480 has an excitation peak at 436 nm and an emission peak at 478 nm, and provides an optimized alternative to BV510. Other dyes that are similar include StarBright Violet 475 (Bio-Rad) While BV480 can be detected on the same filter as BV510, its emmision profile reduces spillover into the BV605, BV650, and BV711 channels. Additionally BV480's excitation profile will reduce cross-laser excitation with the UV laser, resulting in less spillover into UV channels than BV510. These advantages make BV480 an optimal choice for flow cytometry panels using multiple reagents on Violet and/or UV lasers. This dye is part of the Brilliant™ Violet dye line. BV510 and BV480 are the only dyes in the Brilliant™ Violet dye family that are not tandem fluorophores based off the BV421 polymer core, but they have nearly the same maximum excitation.