CD21 Antibody

Recognizes a protein of 140kDa, which is identified as the complement receptor 2(CR2)/CD21. This protein is expressed strongly on mature B cells, follicular dendritic cells and weakly on immature thymocytes and T lymphocytes. In B-cell ontogeny, CD21 appears after the pre-B-stage, is maintained during peripheral B-cell development and is lost upon terminal differentiation into plasma cells. CD21 expression is also gradually lost after stimulation of B cells in vitro.CD21 functions as receptor for C3d, C3dg and iC3b Complement components, for EBV and for IFNalpha.CD21 binds to CD23 and associates with CD19, CD81 and Leu13 to form a large signal-transduction complex involved in B cell activation.