In Western blotting, this antibody detects an antigen of 125 kDa in human liver and 135 kDa in tumors of histiocytic origin. Comparative study of this MAb and a standard CD68 MAb showed that their antigens are different. Its antigen in all macrophage types studied is located on the plasma membrane and within cytoplasmic structures including lysosomes. This MAb shows a restricted reactivity to cells of the monocyte/macrophage system. It specifically reacts with blood monocytes and stains resident macrophages in a wide variety of human tissues. This MAb does not stain antigen-presenting cells, e.g., Langerhans cells. Reportedly, its reactivity is restricted to histiocytes and macrophages.Primary antibodies are available purified, or with a selection of fluorescent CF® Dyes and other labels. CF® Dyes offer exceptional brightness and photostability. Note: Conjugates of blue fluorescent dyes like CF®405S and CF®405M are not recommended for detecting low abundance targets, because blue dyes have lower fluorescence and can give higher non-specific background than other dye colors.