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Gene Review

CD22  -  CD22 molecule

Homo sapiens

Synonyms: B-cell receptor CD22, B-lymphocyte cell adhesion molecule, BL-CAM, SIGLEC-2, SIGLEC2, ...
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Disease relevance of CD22

  • However, none of the 19 CD5+ cases had the phenotype characteristic of chronic lymphocytic leukemia (CD5+, CD23+, FMC7-, weak surface Ig and membrane CD22) [1].
  • A bispecific recombinant immunotoxin, DT2219, targeting human CD19 and CD22 receptors in a mouse xenograft model of B-cell leukemia/lymphoma [2].
  • A novel bispecific single-chain fusion protein, DT2219, was assembled consisting of the catalytic and translocation domains of diphtheria toxin (DT(390)) fused to two repeating sFv subunits recognizing CD19 and CD22 and expressed in Escherichia coli [2].
  • The CD22/antigen receptor association was demonstrated with multiple isotypes (IgM, IgD and IgG) and was evident both in Burkitt lymphoma lines and in tonsil cells [3].
  • The OPF fixation of leukemic cells allowed the simultaneous detection of nuclear TdT in conjunction with membrane CD19, and with membrane and/or cytoplasmic CD22 in common-ALL, as well as with cytoplasmic CD3 in T-ALL cases [4].

High impact information on CD22


Chemical compound and disease context of CD22

  • Anti-Tac(Fv)-PE38 (LMB-2) and RFB4(dsFv)-PE38 (BL22) are two recombinant immunotoxins, targeting CD25 and CD22, respectively, in which Fvs of MAbs targeting these antigens are fused to truncated Pseudomonas exotoxin [6].
  • However, such co-transfected cells can bind to B lymphoma cells in a manner apparently less dependent upon alpha 2-6-linked sialic acid, suggesting CD22-mediated interactions that may not be directly dependent on its lectin function [7].
  • Since B lymphoma cells themselves also express high levels of alpha 2-6-linked sialic acids, their CD22 molecules might be rendered nonfunctional by endogenous ligands [7].
  • Antitumor efficacy of a combination of CMC-544 (inotuzumab ozogamicin), a CD22-targeted cytotoxic immunoconjugate of calicheamicin, and rituximab against non-Hodgkin's B-cell lymphoma [8].
  • Cytotoxicity experiments on CD22-positive cell lines revealed that the PE35 conjugates were more active than the PE38 versions and the presence of the KDEL sequence generally enhanced toxicity by 5-10-fold compared to that of REDLK [9].

Biological context of CD22


Anatomical context of CD22

  • CD22 is a membrane immunoglobulin (mIg)-associated protein of B cells [14].
  • In secondary lymphoid organs, CD22 may be sequestered away from mIg through interactions with counterreceptors on T cells [14].
  • COS cells transfected with a BL-CAM expression vector were immunofluorescently stained positively with two different CD22 antibodies, each of which recognizes a different epitope [11].
  • The most similar proteins in the database were CD22, myelin-associated glycoprotein, Schwann cell myelin protein and CD33 [12].
  • A detailed analysis showed two distinct populations of plasma cells: (1) A population relatively smaller by forward light scattering expressed CD22, CD35, and sigE and was identified as early plasma cells (ie, lymphoplasmacytoid), and (2) a population larger by forward light scattering lacked these markers and was identified as mature plasma cells [15].

Associations of CD22 with chemical compounds

  • Tyrosine-phosphorylated CD22 binds and activates SHP, a protein tyrosine phosphatase known to negatively regulate signaling through mIg [14].
  • Complexes of either CD22/PTP-1C/Syk/PLC-gamma(1) could be isolated from B cells stimulated by BCR engagement or a mixture of hydrogen peroxidase and sodium orthovanadate, respectively [10].
  • The sequence similarity of sialoadhesin to CD22 and related members of the Ig superfamily indicates the existence of a novel family of sialic acid binding proteins involved in cell-cell interactions [12].
  • The B-cell receptor CD22 binds sialic acid linked alpha-2-6 to terminal galactose residues on N-linked oligosaccharides associated with several cell-surface glycoproteins [16].
  • Thus, CD22 beta is a mammalian lectin that can recognize specific N-linked oligosaccharide structures containing alpha-2,6-linked sialic acids [17].
  • Like CD22, Siglec-F mediates endocytosis of anti-Siglec-F and sialoside ligands, a function requiring intact tyrosine-based motifs [18].

Physical interactions of CD22

  • This interaction was further characterized using yeast two-hybrid analysis revealing that Tyr(843) and surrounding amino acids in the cytoplasmic tail of CD22 comprise the primary binding site for AP50 [19].
  • The results obtained indicate that the protein tyrosine kinase Syk interacts with multiple CD22-derived phosphopeptides in both immunoprecipitation and reverse Far Western assays [20].
  • Related immunoglobulin (Ig) superfamily members either failed to bind gangliosides (CD22) or bound with less stringent specificity (sialoadhesin), whereas a modified form of MAG (bearing three of its five extra-cellular Ig-like domains) bound only GQ1b alpha [21].
  • The B lymphocyte adhesion molecule CD22 interacts with leukocyte common antigen CD45RO on T cells and alpha 2-6 sialyltransferase, CD75, on B cells [22].
  • Our results confirm and extend previous observations that CD22 is a sialic acid-binding lectin which interacts with CD45 and other glycoproteins capable of presenting alpha 2,6-linked sialic acid in a manner that promotes high affinity binding [23].

Co-localisations of CD22


Regulatory relationships of CD22


Other interactions of CD22

  • In contrast, CD22 internalization and degradation was unaffected by stimulation of B cell lines with phorbol dibutyrate or ligation of other components of the B cell receptor complex (e.g. CD19, sIgM) with mAbs [26].
  • A single N-linked glycosylation site is implicated in the regulation of ligand recognition by the I-type lectins CD22 and CD33 [30].
  • However, these cells expressed neither CD28, a molecule acquired by plasmocytes, nor CD22 and CD37, which are lost during the transition of plasmablasts to plasmocytes [31].
  • In addition, other investigators reported the binding of Hp to B lymphocytes through the CD22 receptor, and to neutrophils through two different receptors [32].
  • Cells from all cases exhibited moderate to high levels of membrane immunoglobulin, CD22 and CD40 antigens and light chain restriction (kappa/lambda: 1.7/1) [33].

Analytical, diagnostic and therapeutic context of CD22


  1. The immunophenotype of splenic lymphoma with villous lymphocytes and its relevance to the differential diagnosis with other B-cell disorders. Matutes, E., Morilla, R., Owusu-Ankomah, K., Houlihan, A., Catovsky, D. Blood (1994) [Pubmed]
  2. A bispecific recombinant immunotoxin, DT2219, targeting human CD19 and CD22 receptors in a mouse xenograft model of B-cell leukemia/lymphoma. Vallera, D.A., Todhunter, D.A., Kuroki, D.W., Shu, Y., Sicheneder, A., Chen, H. Clin. Cancer Res. (2005) [Pubmed]
  3. Association of CD22 with the B cell antigen receptor. Peaker, C.J., Neuberger, M.S. Eur. J. Immunol. (1993) [Pubmed]
  4. Detection of membrane and intracellular antigens by flow cytometry following ORTHO PermeaFix fixation. Pizzolo, G., Vincenzi, C., Nadali, G., Veneri, D., Vinante, F., Chilosi, M., Basso, G., Connelly, M.C., Janossy, G. Leukemia (1994) [Pubmed]
  5. CD22, a B lymphocyte-specific adhesion molecule that regulates antigen receptor signaling. Tedder, T.F., Tuscano, J., Sato, S., Kehrl, J.H. Annu. Rev. Immunol. (1997) [Pubmed]
  6. Toxin-labeled monoclonal antibodies. Kreitman, R.J. Current pharmaceutical biotechnology. (2001) [Pubmed]
  7. CD22-mediated cell adhesion to cytokine-activated human endothelial cells. Positive and negative regulation by alpha 2-6-sialylation of cellular glycoproteins. Hanasaki, K., Varki, A., Powell, L.D. J. Biol. Chem. (1995) [Pubmed]
  8. Antitumor efficacy of a combination of CMC-544 (inotuzumab ozogamicin), a CD22-targeted cytotoxic immunoconjugate of calicheamicin, and rituximab against non-Hodgkin's B-cell lymphoma. DiJoseph, J.F., Dougher, M.M., Kalyandrug, L.B., Armellino, D.C., Boghaert, E.R., Hamann, P.R., Moran, J.K., Damle, N.K. Clin. Cancer Res. (2006) [Pubmed]
  9. Characterization of RFB4-Pseudomonas exotoxin A immunotoxins targeted to CD22 on B-cell malignancies. Mansfield, E., Pastan, I., FitzGerald, D.J. Bioconjug. Chem. (1996) [Pubmed]
  10. CD22 associates with protein tyrosine phosphatase 1C, Syk, and phospholipase C-gamma(1) upon B cell activation. Law, C.L., Sidorenko, S.P., Chandran, K.A., Zhao, Z., Shen, S.H., Fischer, E.H., Clark, E.A. J. Exp. Med. (1996) [Pubmed]
  11. cDNA cloning of the B cell membrane protein CD22: a mediator of B-B cell interactions. Wilson, G.L., Fox, C.H., Fauci, A.S., Kehrl, J.H. J. Exp. Med. (1991) [Pubmed]
  12. Sialoadhesin, a macrophage sialic acid binding receptor for haemopoietic cells with 17 immunoglobulin-like domains. Crocker, P.R., Mucklow, S., Bouckson, V., McWilliam, A., Willis, A.C., Gordon, S., Milon, G., Kelm, S., Bradfield, P. EMBO J. (1994) [Pubmed]
  13. CD22 regulates B cell receptor-mediated signals via two domains that independently recruit Grb2 and SHP-1. Otipoby, K.L., Draves, K.E., Clark, E.A. J. Biol. Chem. (2001) [Pubmed]
  14. A role in B cell activation for CD22 and the protein tyrosine phosphatase SHP. Doody, G.M., Justement, L.B., Delibrias, C.C., Matthews, R.J., Lin, J., Thomas, M.L., Fearon, D.T. Science (1995) [Pubmed]
  15. Identification and characterization of plasma cells in normal human bone marrow by high-resolution flow cytometry. Terstappen, L.W., Johnsen, S., Segers-Nolten, I.M., Loken, M.R. Blood (1990) [Pubmed]
  16. Regulation of CD45 engagement by the B-cell receptor CD22. Sgroi, D., Koretzky, G.A., Stamenkovic, I. Proc. Natl. Acad. Sci. U.S.A. (1995) [Pubmed]
  17. Natural ligands of the B cell adhesion molecule CD22 beta carry N-linked oligosaccharides with alpha-2,6-linked sialic acids that are required for recognition. Powell, L.D., Sgroi, D., Sjoberg, E.R., Stamenkovic, I., Varki, A. J. Biol. Chem. (1993) [Pubmed]
  18. Distinct endocytic mechanisms of CD22 (Siglec-2) and Siglec-F reflect roles in cell signaling and innate immunity. Tateno, H., Li, H., Schur, M.J., Bovin, N., Crocker, P.R., Wakarchuk, W.W., Paulson, J.C. Mol. Cell. Biol. (2007) [Pubmed]
  19. The B cell coreceptor CD22 associates with AP50, a clathrin-coated pit adapter protein, via tyrosine-dependent interaction. John, B., Herrin, B.R., Raman, C., Wang, Y.N., Bobbitt, K.R., Brody, B.A., Justement, L.B. J. Immunol. (2003) [Pubmed]
  20. Analysis of tyrosine phosphorylation-dependent interactions between stimulatory effector proteins and the B cell co-receptor CD22. Yohannan, J., Wienands, J., Coggeshall, K.M., Justement, L.B. J. Biol. Chem. (1999) [Pubmed]
  21. Myelin-associated glycoprotein binding to gangliosides. Structural specificity and functional implications. Schnaar, R.L., Collins, B.E., Wright, L.P., Kiso, M., Tropak, M.B., Roder, J.C., Crocker, P.R. Ann. N. Y. Acad. Sci. (1998) [Pubmed]
  22. The B lymphocyte adhesion molecule CD22 interacts with leukocyte common antigen CD45RO on T cells and alpha 2-6 sialyltransferase, CD75, on B cells. Stamenkovic, I., Sgroi, D., Aruffo, A., Sy, M.S., Anderson, T. Cell (1991) [Pubmed]
  23. The B-cell adhesion molecule CD22 is cross-species reactive and recognizes distinct sialoglycoproteins on different functional T-cell sub-populations. Sgroi, D., Stamenkovic, I. Scand. J. Immunol. (1994) [Pubmed]
  24. Expression and structure of CD22 in acute leukemia. Boué, D.R., LeBien, T.W. Blood (1988) [Pubmed]
  25. CD19 regulates intrinsic B lymphocyte signal transduction and activation through a novel mechanism of processive amplification. Fujimoto, M., Poe, J.C., Hasegawa, M., Tedder, T.F. Immunol. Res. (2000) [Pubmed]
  26. Constitutive endocytosis and degradation of CD22 by human B cells. Shan, D., Press, O.W. J. Immunol. (1995) [Pubmed]
  27. CD19 and CD22 regulate a B lymphocyte signal transduction pathway that contributes to autoimmunity. Tedder, T.F., Sato, S., Poe, J.C., Fujimoto, M. The Keio journal of medicine. (2000) [Pubmed]
  28. CD22 cross-linking generates B-cell antigen receptor-independent signals that activate the JNK/SAPK signaling cascade. Tuscano, J.M., Riva, A., Toscano, S.N., Tedder, T.F., Kehrl, J.H. Blood (1999) [Pubmed]
  29. CD22-mediated stimulation of T cells regulates T-cell receptor/CD3-induced signaling. Aruffo, A., Kanner, S.B., Sgroi, D., Ledbetter, J.A., Stamenkovic, I. Proc. Natl. Acad. Sci. U.S.A. (1992) [Pubmed]
  30. A single N-linked glycosylation site is implicated in the regulation of ligand recognition by the I-type lectins CD22 and CD33. Sgroi, D., Nocks, A., Stamenkovic, I. J. Biol. Chem. (1996) [Pubmed]
  31. Human circulating specific antibody-forming cells after systemic and mucosal immunizations: differential homing commitments and cell surface differentiation markers. Quiding-Järbrink, M., Lakew, M., Nordström, I., Banchereau, J., Butcher, E., Holmgren, J., Czerkinsky, C. Eur. J. Immunol. (1995) [Pubmed]
  32. Haptoglobin interacts with the human mast cell line HMC-1 and inhibits its spontaneous proliferation. El-Ghmati, S.M., Arredouani, M., Van Hoeyveld, E.M., Ceuppens, J.L., Stevens, E.A. Scand. J. Immunol. (2002) [Pubmed]
  33. Cytokine response of B lymphocytes from splenic lymphoma with villous lymphocytes: correlation with TNF-RII (p75) and CD11c expression. Treton, D., Valensi, F., Troussard, X., Gras, G., Flandrin, G., Galanaud, P., Richard, Y. Hematology and cell therapy. (1996) [Pubmed]
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