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™ BUV661 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 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.