FLUOROCHROMES FITC, PE, APC, AL. FLUOR 647, CF-BLUE.

It is a receptor for the C3d complement fragment and for Epstein Barr virus (EBV), found on mature B cells, follicular dendritic cells, andsome epithelial cells. It is also weakly expressed on a subset of mature T cells and thymocytes. This clone also cross-reacts with a major subset of, but not all, peripheral blood CD20 + lymphocytes of baboon, and both rhesus and cynomolgus macaque monkeys. A subset of CD3 + cells is also CD21 +.The monoclonal antibody is directed against the CD21-antigen, which is expressed on normal Ig-positive B-cells from peripheral blood and lymphoid tissues and on dendritic cells of germinal centres. Its expression is lost on activated B-cells. The distinct distribution among B-cell malignancies differs from other B-cell markers e.g. CD19 and CD20.