The RP/14 monoclonal antibody specifically binds to CD180, the "radioprotective" 105 kDa (RP105) antigen expressed on mature B lymphocytes. Like other members of the Toll-like Receptor (TLR) family, the extracellular region of CD180 contains tandem repeats of a leucine-rich motif flanked by regions containing conserved cysteines. These characteristic structural components of TLR may mediate protein-protein interactions and regulation of signal transduction involved in innate immune responses. Furthermore, CD180 associates with the secretory protein MD-1 on the cell surface. Cross-linking of cell-surface CD180 with the RP/14 antibody induces activation signals in B lymphocytes. Despite the expression of CD180 on lymphocytes of all strains tested (BALB/c, BALB/c.xid, C3H, C57BL/6, CBA/N, and 129/Sv), some strains (BALB/c.xid, C57BL/6.xid, CBA/N, 129/Sv, and 129/Ola) display deficient responses to that stimulatory effects of mAb RP/14.
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.