The HIS57 monoclonal antibody reacts with an unknown antigen that is highly expressed by most marginal zone B (MZ-B) cells in the spleen. In contrast, this antigen is weakly expressed, or not expressed at all, by other B-cell subpopulations. Rat MZ-B cells express low levels of CD45R (mAb HIS24) and sIgD and high levels of sIgM. The HIS57 mAb does not stain granulocytes and thymocytes. Immunohistochemical staining of normal spleen sections with HIS57 mAb produced a positive signal in the marginal zone and, to a lesser extent, in B-cell follicles. This marker can be used in combination with CD45R, sIgD, and sIgM t0 identify MZ-B cells in the rat.
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.