Specificity:Recognizes human dendritic cells and a proportion of B lymphocytes. Reacts with an epitope within the class II MHC complex. Binds to an epitope expressed by antigen presenting cells. Within the macrophage/dendritic cell populations the epitope seen is coexpressed with by a subset of cells that exhibit suppressive activity on T cell stimulation. Will not bind to monocytes or any cells within the granulocyte series.