The L106 monoclonal antibody specifically recognizes CD134 which is also known as OX40, OX40L receptor or TAX transcriptionally-activated glycoprotein 1 receptor (TXGP1L). CD134 is a ~48 kDa type I transmembrane glycoprotein that is encoded by TNFRSF4 (TNF receptor superfamily member 4) and belongs to the TNF/NGF receptor family. By sequence analysis, CD134 is related to the antigen recognized by the rat monoclonal antibody Ox 40. The CD134 antigen (Human Ox 40) is found on activated peripheral CD4+ T lymphocytes and a subset of activated CD8+ T lymphocytes. It is not expressed on CD3-activated purified CD8+ T lymphocytes. It is also present on HUT-102, an HTLV- 1-infected T-lymphocyte line. Its ligand, gp34 (CD252 or Ox 40 Ligand encoded by TNFSF4), is found on some antigen presenting cells including B cells and dendritic cells as well as Epstein Barr virus (EBV)-transformed B lymphocytes. Preliminary evidence suggests a possible role for CD134 antigen in graft rejection.
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.