The WT.5 monoclonal antibody specifically recognizes the alpha subunit of LFA-1 (αLβ2 integrin, CD11a/CD18), a heterodimeric surface glycoprotein which is found on the majority of leukocytes, but not on peritoneal macrophages or peritoneal mast cells. LFA-1 mediates a variety of heterotypic and homotypic intercellular adhesions through interaction with ICAM-1 (CD54) and ICAM-2 (CD102). WT.1 mAb recognizes both the activated and unactivated forms of LFA-1. It inhibits the binding of LFA-1 to ICAM-1 in several in vitro assays, including binding of Concanavalin A-stimulated lymphocytes (Con A blasts) to purified ICAM-1 and Mg2+-dependent aggregation of concanavalin A-stimulated blasts. It has also been reported to inhibit leukocyte infiltration in several in vivo models of inflammation.
The antibody was conjugated to BD Horizon™ BV650 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 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.