The J168-540 monoclonal antibody specifically binds to human CD272, also known as BTLA (B and T lymphocyte attenuator), an inhibitory receptor expressed in bone marrow and thymus on developing B and T cells. In the periphery, BTLA is expressed by B cells, T cells, bone marrow-derived dendritic cells, and macrophages. After T cell activation, BTLA appears to be expressed at higher levels on Th1 cell populations than in Th2 cell populations. Upon binding the herpesvirus entry mediator (HVEM/LIGHT-R/CD270), CD272 undergoes tyrosine phosphorylation and inhibits T cell proliferation in a BTLA-dependent manner. CD272 has structural similarities to two other lymphocyte inhibitory receptors, CTLA-4 and PD-1 and is a member of the CD28-like family of coreceptors. Based on these observations, CD272 is considered to be a negative regulator of lymphocyte activation and/or function.
The antibody was conjugated to BD Horizon™ BUV496 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 496-nm. BD Horizon BUV496 can be excited by the ultraviolet laser (355 nm) and detected with a 515/30 nm filter with a 450LP. Due to the excitation of the acceptor dye by other laser lines, there may be significant spillover into the channel detecting BD Horizon V500 or BV510 (eg, 525/40-nm filter). However, the spillover can be corrected through compensation as with any other dye combination.