The A1/CD307d monoclonal antibody specifically recognizes CD307d which is also known as Fc receptor-like protein 4 (FCRL4), Fc receptor homolog 4 (FCRH4), or Immune receptor translocation-associated protein 1 (IRTA1). CD307d (FCRL4) is a type I transmembrane glycoprotein that belongs to the IRTA gene family within the Ig gene superfamily. It has four extracellular Ig-like domains, a helical transmembrane region, and two consensus immunoreceptor tyrosine-based inhibition motifs (ITIMs) and one immunoreceptor tyrosine-based switch motif (ITSM) in its cytoplasmic domain. CD307d (FCRL4) binds to aggregated IgA and IgG, and its highest level of expression is on memory B cells in mucosa-associated lymphoid tissues (MALT). Chromosomal abnormalities in the region of the FCRL4 gene are associated with non-Hodgkin lymphoma and multiple myeloma, and CD307d (FCRL4) may play a role in HIV-induced memory B cell dysfunction.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).