The HMBT-6B2 monoclonal antibody specifically binds to CD272 which is also known as B- and T-lymphocyte attenuator (BTLA). CD272 is a type 1 transmembrane glycoprotein and a member of the Ig superfamily. CD272 is variably expressed on developing and mature T and B lymphocytes, NKT cells, NK cells, macrophages and dendritic cells. CD272 expression is upregulated by activated T cells including Th1, Th2, and T follicular helper cells and by anergic T cells. CD272 is structurally similar to CD152/CTLA-4 and CD279/PD-1 and functions as a coinhibitory receptor for B and T cell responses. Herpesvirus entry mediator (HVEM), also known as CD270 and LIGHT-R, has been identified as a ligand for CD272. The crosslinking of CD272 by HVEM inhibits T-cell proliferation and cytokine production.
The antibody was conjugated to BD Horizon™ BV711 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 711-nm. BD Horizon BV711 can be excited by the violet laser and detected in a filter used to detect Cy™5.5 / Alexa Fluor® 700-like dyes (eg, 712/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there may be moderate spillover into the Alexa Fluor® 700 and PerCP-Cy5.5 detectors. However, the spillover can be corrected through compensation as with any other dye combination.