CD21 (HI21a) Antibody

The CD21 (HI21a) Antibody recognizes a 145-kDa type-I transmembrane glycoprotein which is a receptor for C3d complement (CR2) and Epstein-Barr virus (EBVR). CD21 antigen is mainly expressed on mature B cells, follicular dendritic cells, and weakly expressed on subsets of normal thymocytes and T cells, and certain epithelial cells. CD21 is absent from NK cells, granulocytes and monocytes. Some cell populations of B-CLL and T-ALL also express CD21 antigen. CD21 may play a role in B cell activation and proliferation.