The MR1 monoclonal antibody specifically binds to CD154 (CD40 Ligand, gp39), an accessory molecule expressed on activated T helper (CD4+) lymphocytes. CD154 has also been detected on other types of leukocytes, including CD8+ T cells, medullary thymocytes, activated CD4+ NK-T cells, and human NK cells. CD154 plays an important role in costimulatory interactions between T and B lymphocytes and between antigen-presenting cells and lymphocytes, regulating the immune response at multiple levels. MR1 mAb inhibits in vitro activation of B lymphocytes by T helper cells by blocking interaction of gp39 with CD40. In vitro interactions of T cells and antigen-presenting cells can also be blocked by the MR1 antibody. In vivo treatment with MR1 antibody blocks the development of experimental autoimmune disease, inhibits formation of germinal centers and generation of memory B cells, reduces T-lymphocyte responses to allogeneic cells and allografts, prevents intrathymic deletion of self-reactive T lymphocytes, and disrupts antigen-specific T-cell responses.
This antibody is conjugated to BD Horizon™ BV605 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max of 602-nm, BD Horizon BV605 can be excited by a violet laser and detected with a standard 610/20-nm filter set. BD Horizon BV605 is a tandem fluorochrome of BD Horizon BV421 and an acceptor dye with an Em max at 605-nm. Due to the excitation of the acceptor dye by the green (532 nm) and yellow-green (561 nm) lasers, there will be significant spillover into the PE and BD Horizon PE-CF594 detectors off the green or yellow-green lasers. BD Horizon BV605 conjugates are very bright, often exhibiting brightness equivalent to PE conjugates and can be used as a third color off of the violet laser.