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.
The antibody was conjugated to BD Horizon Red 718, which has been developed exclusively for BD Biosciences as a better alternative to Alexa Fluor® 700. BD Horizon Red 718 can be excited by the red laser (628 – 640 nm) and, with an Em Max around 718 nm, it can be detected using a 730/45 nm filter. Due to similar excitation and emission properties, we do not recommend using R718 in combination with APC-R700 or Alexa Fluor® 700.