CD21

Marker for: B cells, follicular dendritic cells

Structure: Transmembrane glycoprotein (145 kDa).

Note: CD21 is involved in B cell activation and proliferation. Belongs to the complement regulatory protein family and is encoded by the CR2 (Complement C3d Receptor 2) gene (see there).

CD21 is a receptor for Epstein-Barr virus (EBV). Marks the germinal centers of reactive lymphoid follicles. CD21 is essential for the infection process.

However, for extranodal (NK)/T-cell lymphoma, an aggressive malignant lymphoma associated with EBV infection, EBV infection of NK cells occurs via direct transfer of viral episomes independent of EBV-positive(CD21-positive) B cells (Lee JH et al 2018).

Application: FACS, IHC (P) (G), IF.

(see also below) Cluster of differentiation

1. Hantschke M et al (2016) Immunohistological techniques. In: L. Cerroni et al. histopathology of the skin. Springer publishing house Berlin-Heidelberg p. 26-33.
2. Lee JH et al (2018) CD21-independent Epstein-Barr virus entry into NK cells.
   Cell Immunol 327:21-25.