Description: The M3/84 monoclonal antibody reacts with mouse Mac-3, the 110 kDa protein expressed by mononuclear phagocytes. The Mac-3 antigen is expressed intracellularly by bone marrow monocyte lineage and is upregulated during macrophage differentiation. Peritoneal and tissue macrophages, dendritic cells, and endothelial cells express this antigen on their surface. It is reported that Mac-3 may be identical to CD107b.