CD33 molecule (Sialic acid-binding Ig-like lectin 3) (CD33)

CD33 (Sialic acid-binding Ig-like lectin 3, Siglec-3) is a transmembrane inhibitory receptor of the immunoglobulin superfamily, mainly expressed on cells of the myeloid lineage (monocytes, myeloid progenitors, some granulocytes, and dendritic cells), though it can be present on some lymphoid cells. CD33 contains an extracellular region with two immunoglobulin-like domains and cytoplasmic ITIM motifs that recruit SHP1/2 phosphatases, leading to inhibition of cell activation and modulation of immune response. CD33 acts as an immune checkpoint and is a well-established therapeutic target in acute myeloid leukemia, targeted by antibody-drug conjugates like gemtuzumab ozogamicin. Genetic variants in CD33 are implicated in Alzheimer's disease risk, potentially by altering microglial activation or phagocytosis of amyloid-β. The combination “CD33 and DNA” is not a correct or standard molecular target; therapeutically, drugs such as gemtuzumab ozogamicin target CD33 and deliver toxins that damage DNA, but “CD33 and DNA” does not represent a unique receptor, protein, or target entity in itself.

Other names

Siglec-3Sialic acid-binding Ig-like lectin 3SIGLEC3SIGLEC-3gp67p67

Antibody-drug conjugate binding induces internalization and payload-mediated DNA damage (as with gemtuzumab ozogamicin; calicheamicin payload causes DNA strand breaks/crosslinks). Recruitment of SHP1/SHP2 phosphatases via ITIM motifs inhibits downstream cell activation pathways.