The AER-37 (CRA-1) monoclonal antibody specifically recognizes FcεRIα which is also known as the high affinity immunoglobulin epsilon receptor subunit alpha (Fc-epsilon RI-alpha). FcεRIα is a type I transmembrane glycoprotein that is encoded by FCER1A (Fc fragment of IgE receptor Ia) which belongs to the Ig gene superfamily. FcεRIα serves as the binding subunit for the Fc region of IgE. It forms part of a heterotetrameric, high-affinity IgE Fc receptor (FceR1/FcεR1) that includes signal transducing subunits, one β-chain (FcεRIβ encoded by MS4A2) and two disulfide-linked γ-subunits (FcεRIγ encoded by FCER1G). FcεRIα is normally expressed on basophils and mast cells and can also be expressed on some monocytes, Langerhans cells, dendritic cells, and eosinophils from allergic donors. FcεRIα plays a major role in allergic responses and in the presentation of allergens to the immune system. The AER-37 antibody reportedly does not compete with IgE for FceR1 binding.
The antibody was conjugated to BD Horizon™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.