From Wikipedia, the free encyclopedia
Jump to: navigation, search
CD22 molecule
Symbols CD22 ; SIGLEC-2; SIGLEC2
External IDs OMIM107266 MGI88322 HomoloGene31052 ChEMBL: 3218 GeneCards: CD22 Gene
RNA expression pattern
PBB GE CD22 38521 at tn.png
PBB GE CD22 204581 at tn.png
PBB GE CD22 217422 s at tn.png
More reference expression data
Species Human Mouse
Entrez 933 12483
Ensembl ENSG00000012124 ENSMUSG00000030577
UniProt P20273 P35329
RefSeq (mRNA) NM_001185099 NM_001043317
RefSeq (protein) NP_001172028 NP_001036782
Location (UCSC) Chr 19:
35.32 – 35.35 Mb
Chr 7:
30.87 – 30.88 Mb
PubMed search [1] [2]

CD22, or cluster of differentiation-22, is a molecule belonging to the SIGLEC family of lectins.[1] It is found on the surface of mature B cells and to a lesser extent on some immature B cells. Generally speaking, CD22 is a regulatory molecule that prevents the overactivation of the immune system and the development of autoimmune diseases.[2]

CD22 is a sugar binding transmembrane protein, which specifically binds sialic acid with an immunoglobulin (Ig) domain located at its N-terminus. The presence of Ig domains makes CD22 a member of the immunoglobulin superfamily. CD22 functions as an inhibitory receptor for B cell receptor (BCR) signaling. It is also involved in the B cell trafficking to Peyer's patches in mice.[3]

An immunotoxin, BL22, that targets this receptor is being tested at the NIH.[4]

External links[edit]


CD22 has been shown to interact with Grb2,[5][6] PTPN6,[6][7][8][9][10] LYN,[5][8] SHC1[5] and INPP5D.[5]


  1. ^ Crocker; et al. (1998). "Siglecs: a family of sialic-acid binding lectins". Glycobiology 8 (2): v. doi:10.1093/glycob/8.2.0. PMID 9498912. 
  2. ^ Hatta; et al. (1999). "Identification of the gene variations in human CD22". 
  3. ^ Lee; et al. (Oct 2014). "Transcriptional programs of lymphoid tissue capillary and high endothelium reveal control mechanisms for lymphocyte homing". Nature Immunology 15 (10): 982–995. doi:10.1038/ni.2983. PMID 25173345. 
  4. ^ "BL22 Immunotoxin in Treating Patients Previously Treated With Cladribine for Hairy Cell Leukemia". - U.S. National Institutes of Health. Retrieved 2008-02-19. 
  5. ^ a b c d Poe, J C; Fujimoto M; Jansen P J; Miller A S; Tedder T F (June 2000). "CD22 forms a quaternary complex with SHIP, Grb2, and Shc. A pathway for regulation of B lymphocyte antigen receptor-induced calcium flux". J. Biol. Chem. (UNITED STATES) 275 (23): 17420–7. doi:10.1074/jbc.M001892200. ISSN 0021-9258. PMID 10748054. 
  6. ^ a b Otipoby, K L; Draves K E; Clark E A (November 2001). "CD22 regulates B cell receptor-mediated signals via two domains that independently recruit Grb2 and SHP-1". J. Biol. Chem. (United States) 276 (47): 44315–22. doi:10.1074/jbc.M105446200. ISSN 0021-9258. PMID 11551923. 
  7. ^ Blasioli, J; Paust S; Thomas M L (January 1999). "Definition of the sites of interaction between the protein tyrosine phosphatase SHP-1 and CD22". J. Biol. Chem. (UNITED STATES) 274 (4): 2303–7. doi:10.1074/jbc.274.4.2303. ISSN 0021-9258. PMID 9890995. 
  8. ^ a b Greer, S F; Justement L B (May 1999). "CD45 regulates tyrosine phosphorylation of CD22 and its association with the protein tyrosine phosphatase SHP-1". J. Immunol. (UNITED STATES) 162 (9): 5278–86. ISSN 0022-1767. PMID 10228003. 
  9. ^ Law, C L; Sidorenko S P; Chandran K A; Zhao Z; Shen S H; Fischer E H; Clark E A (February 1996). "CD22 associates with protein tyrosine phosphatase 1C, Syk, and phospholipase C-gamma(1) upon B cell activation". J. Exp. Med. (UNITED STATES) 183 (2): 547–60. doi:10.1084/jem.183.2.547. ISSN 0022-1007. PMC 2192439. PMID 8627166. 
  10. ^ Adachi, T; Wienands J; Wakabayashi C; Yakura H; Reth M; Tsubata T (July 2001). "SHP-1 requires inhibitory co-receptors to down-modulate B cell antigen receptor-mediated phosphorylation of cellular substrates". J. Biol. Chem. (United States) 276 (28): 26648–55. doi:10.1074/jbc.M100997200. ISSN 0021-9258. PMID 11356834.