CD22

CD22, or is_associated_with::cluster of differentiation-22, is a molecule belonging to the is_associated_with::SIGLEC family of is_associated_with::lectins. It is found on the surface of mature B cells and to a lesser extent on some immature B cells. Generally speaking, CD22 is a regulatory molecule that prevents the overactivation of the immune system and the development of autoimmune diseases.

CD22 is a sugar binding is_associated_with::transmembrane protein, which specifically binds is_associated_with::sialic acid with an immunoglobulin (Ig) domain located at its is_associated_with::N-terminus. The presence of Ig domains makes CD22 a member of the is_associated_with::immunoglobulin superfamily. CD22 functions as an inhibitory receptor for is_associated_with::B cell receptor (BCR) signaling. It is also involved in the B cell trafficking to Peyer's patches in mice.

An immunotoxin, is_associated_with::BL22, that targets this receptor is being tested at the is_associated_with::NIH.

Interactions
CD22 has been shown to interact with is_associated_with::Grb2, is_associated_with::PTPN6,    is_associated_with::LYN,  is_associated_with::SHC1 and is_associated_with::INPP5D.