The ACT35 monoclonal antibody specifically binds to CD134 which is also known as OX40. The 35 kDa CD134 polypeptide is encoded by the TNFRSF4 gene. CD134 is a type I integral membrane glycoprotein and member of the tumor necrosis factor/nerve growth factor receptor (TNFR/NGFR) family. CD134 is expressed on activated T lymphocytes, hematopoietic precursor cells and fibroblasts. CD134 functions as a T cell costimulatory receptor when bound by OX40 Ligand/TNFSF4 that is expressed by antigen presenting cells. CD134 thereby plays roles in T-cell activation as well as the regulation of differentiation, proliferation or apoptosis of normal and malignant lymphoid cells. Analysis of the nucleotide sequence of the human TNFRSF4 cDNA reveals strong homology with the rat Tnfrsf4 cDNA sequence. OX40 was clustered as CD134 in the Sixth International Workshop on Human Leukocyte Differentiation Antigens.
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.