B lymphocyte antigen CD22 (CD22)

B lymphocyte antigen CD22 (CD22) is a type I transmembrane glycoprotein belonging to the sialic acid-binding immunoglobulin-like lectin (Siglec) family, predominantly expressed on the surface of mature B cells[1][3][4][7]. It functions as an adhesion and inhibitory receptor that regulates B cell receptor (BCR) signaling by recruiting phosphatases like SHP-1 to its phosphorylated immunoreceptor tyrosine-based inhibitory motifs (ITIMs), dampening B cell activation and thus maintaining immune tolerance[4][5][7]. CD22 binds α2,6-linked sialic acid residues on glycoproteins in both cis (on the same cell) and trans (on other cells) configurations, affecting both B cell interactions and migration[1][7]. Due to its restricted expression and critical immune regulatory role, CD22 is an established therapeutic target in various B cell-mediated diseases, with monoclonal antibodies and antibody-drug conjugates utilized clinically and in research for B cell depletion, immunomodulation, and as a biomarker for disease monitoring and treatment response[1][3][4][7].

Other names

Siglec-2Cluster of differentiation 22SIGLEC2

Antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity via anti-CD22 monoclonal antibodies Internalization and delivery of cytotoxic payload (immunotoxins, ADCs) Inhibition of B cell signaling leading to B cell depletion or anergy