CD22 (Siglec-2) receptor (CD22)

CD22 is a B‑cell–restricted, type I transmembrane inhibitory co‑receptor of the B‑cell receptor, belonging to the SIGLEC family and immunoglobulin superfamily; its ectodomain binds α2,6‑linked sialic acid ligands, while its cytoplasmic tail contains ITIMs that recruit SHP‑1 to dampen BCR signaling and calcium mobilization, helping maintain B‑cell activation thresholds and homeostasis. Its restricted B‑cell expression, constitutive endocytosis, and internalization make it an attractive target for therapeutic antibodies, antibody–drug conjugates, and targeted delivery of immunotoxins or ionizing radiation to CD22‑positive cells in B‑cell cancers and autoimmune conditions.

Other names

Cluster of differentiation 22Siglec-2 (sialic acid-binding Ig-like lectin 2)B‑cell receptor CD22

Antibody binding to CD22 to modulate/inhibit BCR signaling and induce B‑cell depletion or anergy. Targeted delivery via CD22-mediated endocytosis enabling internalization of toxins or radioisotopes to CD22+ B cells. Inhibition mediated through ITIM motifs recruiting SHP‑1, dampening BCR signaling pathways and calcium flux.