The 232-5 monoclonal antibody specifically recognizes Butyrophilin 3 (BTN3), which is also known as CD277. BTN3 is comprised of three structurally related members, BTN3A1, BTN3A2, and BTN3A3. BTN3 molecules are transmembrane type 1 glycoproteins that belong to the Ig superfamily. The 232-5 antibody recognizes the variable region of the extracellular domains of BTN3 molecules. BTN3 molecules are differentially expressed by T, NKT, B, and NK cells, monocytes, macrophages, dendritic cells, as well as some stem cells and tumor cells. BTN3 expression is decreased upon lymphocyte activation. The extracellular domain of CD277 is structurally related to the B7 family of proteins that regulate T cell activation. A soluble form of the 232-5 antibody can serve as an agonist in BTN3-mediated regulation of anti-CD3 ± anti-CD28 antibody activated CD4+ or CD8+ T cells.
The antibody was conjugated to BD Horizon™ BUV496 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 496-nm. BD Horizon BUV496 can be excited by the ultraviolet laser (355 nm) and detected with a 515/30 nm filter with a 450LP. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into the channel detecting BD Horizon V500 or BV510 (eg, 525/40-nm filter). However, the spillover can be corrected through compensation as with any other dye combination.