The A59 monoclonal antibody specifically recognizes CD89. CD89 is the Fc receptor for IgA (FcαR), a 55-75 kDa glycoprotein expressed exclusively on cells of granulocytic and monocyte/macrophage lineages in peripheral blood, but not on lymphocytes. It is also expressed on promyelocytes in bone marrow and in the cytoplasm of fixed monocytes. This mAb does not block IgA binding and is more efficient than native IgA ligands in the isolation of FcαR molecules. FcαR plays a role in triggering phagocytosis and respiratory burst.
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.