CD22

CD22 Full Name

CD22 antigen

CD22 Introduction

CD22 is a B-cell–restricted transmembrane glycoprotein belonging to the sialic acid–binding immunoglobulin-like lectin (Siglec) family and is expressed from late pro-B cells through mature B lymphocytes, while being absent on hematopoietic stem cells and most non-B tissues. This lineage-specific expression pattern makes CD22 an especially attractive therapeutic target in B-cell malignancies, where precise tumor recognition and reduced off-tumor toxicity are critical clinical needs. Unlike more ubiquitously expressed immune markers, CD22 provides a biologically stable anchor for B-cell–directed therapies, supporting its long-standing use in antibody-drug conjugates and, more recently, in next-generation cellular immunotherapies.

Functionally, CD22 acts as a key inhibitory regulator of B-cell receptor (BCR) signaling, maintaining immune homeostasis by dampening excessive B-cell activation through its immunoreceptor tyrosine-based inhibitory motifs. Upon ligand binding and internalization, CD22 rapidly undergoes endocytosis, a feature that is particularly advantageous for therapeutic exploitation. In the context of CAR-T cell therapy, this internalization capacity enables efficient target engagement and cytotoxic signaling, while dual-targeting strategies that combine CD22 with CD19 have proven effective in mitigating antigen escape. Clinical and translational studies consistently show that targeting CD22, either sequentially or simultaneously with CD19, can restore deep and durable responses in patients who relapse after single-antigen CAR-T treatment, addressing one of the most pressing challenges in cellular immunotherapy.

Disease-wise, CD22 has emerged as a critical target across a spectrum of refractory or relapsed B-cell malignancies, including B-cell acute lymphoblastic leukemia and B-cell non-Hodgkin lymphomas. Multiple clinical trials demonstrate that CD19/CD22 bispecific or dual-targeting CAR-T therapies can achieve remarkably high objective response and complete remission rates, even in heavily pretreated patients and in those with central nervous system involvement. These outcomes highlight CD22's value not only as a backup antigen in cases of CD19 loss, but also as a core component of more resilient therapeutic designs. As antigen heterogeneity and immune escape continue to limit long-term efficacy in B-cell cancers, CD22 stands out as a clinically validated, mechanistically sound target that supports more durable disease control and improved patient stratification in modern immuno-oncology.

Alternate Names for CD22

CD22; CD22 antigen; Lyb8; Lyb-8; A530093D23; B-cell receptor CD22; BL-CAM; siglec-2; T-cell surface antigen Leu-14; B-lymphocyte cell adhesion molecule; sialic acid-binding Ig-like lectin 2;

• Immunohistochemistry Antibodies for Pathology

• 1.Dai H, et al.; Bispecific CAR-T cells targeting both CD19 and CD22 for therapy of adults with relapsed or refractory B cell acute lymphoblastic leukemia. J Hematol Oncol. 2020, 13(1):30.
  Zhang Y, et al.; A novel and efficient CD22 CAR-T therapy induced a robust antitumor effect in relapsed/refractory leukemia patients when combined with CD19 CAR-T treatment as a sequential therapy. Exp Hematol Oncol. 2022, 11(1):15.