The Ber-ACT8 monoclonal antibody specifically binds to the human mucosal lymphocyte antigen 1 (HML-1). This is a 175 kDa type I transmembrane glycoprotein, also known as integrin αE (ITGAE, Integrin alpha-E) and CD103. It is found on >90% of intestinal intraepithelial lymphocytes (iIEL) associated with integrin β7. CD103 is also expressed on lamina propria T lymphocytes in the intestine and on phytohemagglutinin-stimulated peripheral blood lymphocytes. It is rarely expressed on resting peripheral blood lymphocytes. It has been suggested that CD103 may have an accessory function for activation of iIEL. CD103 has been reported as a useful tool in hairy cell leukemia research.
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.