CD21 Rabbit Polyclonal Antibody

Function

CD21 is a type I integral membrane glycoprotein that serves as a receptor for the C3d complement fragment and for the Epstein-Barr virus. It plays a role in B cell activation and proliferation and undergoes phosphorylation after B cell activation with phorbol esters. CD21 is expressed on mature B cells, follicular dendritic cells, pharyngeal and cervical epithelial cells and a subset of thymocytes. The adaptive immune response is tightly regulated to limit responding cells in an antigen-specific manner. On B cells, co-receptors CD21/CD19 modulate the strength of B cell Ag receptor (BCR) signals, thereby influencing cell fate. Complement receptor (CR) type 2 (CR2/ CD21) is normally expressed during the immature and mature stages of B cell development. In association with CD19, CD21 plays an important role in enhancing mature B cell responses to foreign antigens.

Background References

1. Barel M et al. Binding sites of the Epstein-Barr virus and C3d receptor (CR2, CD21) for its three intracellular ligands, the p53 anti-oncoprotein, the p68 calcium binding protein and the nuclear p120 ribonucleoprotein. Mol Immunol 32: 389-397 (1995).

2. Tanner J et al. Soluble gp350/220 and deletion mutant glycoproteins block Epstein-Barr virus adsorption to lymphocytes. J Virol 62: 4452-4464 (1988).

Sequence Similarity

Belongs to the receptors of complement activation (RCA) family.

Tissue Specificity

Mature B-lymphocytes, T-lymphocytes, pharyngeal epithelial cells, astrocytes and follicular dendritic cells of the spleen.

Subcellular Location

Membrane.

UNIPROT

SwissProt: P20023 Human

Synonyms