Complement receptor 2


Complement receptor 2
Complement component (3d/Epstein Barr virus) receptor 2

PDB rendering based on 1ghq.
Identifiers
Symbols CR2; C3DR; CD21; SLEB9
External IDs OMIM120650 MGI88489 HomoloGene55611 GeneCards: CR2 Gene
RNA expression pattern
PBB GE CR2 205544 s at tn.png
More reference expression data
Orthologs
Species Human Mouse
Entrez 1380 12902
Ensembl ENSG00000117322 ENSMUSG00000026616
UniProt P20023 Q6LAP4
RefSeq (mRNA) NM_001006658.2 NM_007758.2
RefSeq (protein) NP_001006659.1 NP_031784.1
Location (UCSC) Chr 1:
207.63 – 207.66 Mb
Chr 1:
196.96 – 197 Mb
PubMed search [1] [2]

Complement component (3d/Epstein Barr virus) receptor 2, also known as CR2 and CD21, is a protein involved in the complement system. It binds to iC3b (inactive derivative of C3b), C3dg, or C3d.[1] B cells have CR2 receptors on their surfaces, allowing the complement system to play a role in B-cell activation and maturation [2]

Contents

Interactions

CR2 on mature B cells form a complex with two other membrane proteins, CD19 and CD81(=TAPA-1). The CR2-CD19-CD81 complex is often called the B cell coreceptor complex,[3] because CR2 binds to antigens through attached C3d (or iC3b or C3dg) when the membrane IgM binds to the antigen. This results in the B cell having greatly enhanced response to the antigen.[1]

Complement receptor 2 has been shown to interact with CD19.[4][5]

Epstein-Barr virus (EBV) binds to B cells at CR2 during infection of these cells. Yefenof et al. (1976) found complete overlapping of EBV receptors and C3 receptors on human B cells.[2][6]

Immunohistochemistry

Although CR2 is present on all mature B-cells and follicular dendritic cells (FDCs), this only readily apparent when immunohistochemistry is performed on frozen sections. In more conventional paraffin-embedded tissue samples, only the follicular dendritic cells retain the staining pattern. As a result, CR2, more commonly called CD21 in the context of immunohistochemistry, can be used to demonstrate the FDC meshwork in lymphoid tissue.

This feature can be useful in examining tissue where the normal germinal centres have been effaced by disease processes, such as HIV infection. The pattern of the FDC meshwork may also be altered in some neoplastic conditions, such as B-cell MALT lymphomas, mantle cell lymphoma, and some T cell lymphomas. Castleman's disease is typified by the presence of abnormal FDCs, and both this, and malignant FDC tumours may therefore be demonstrated using CR2/CD21 antibodies.[7]

References

  1. ^ a b Frank K, Atkinson JP (2001). "Complement system." In Austen KF, Frank K, Atkinson JP, Cantor H. eds. Samter's Immunologic Diseases, 6th ed. Vol. 1, p. 281-298, Philadelphia: Lippincott Williams & Wilkins, ISBN 0781721202.
  2. ^ a b "Entrez Gene: CR2 complement component (3d/Epstein Barr virus) receptor 2". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=1380. 
  3. ^ Abbas AK, Lichtman AH (2003). Cellular and Molecular Immunology, 5th ed. Philadelphia: Saunders, ISBN 0-7216-0008-5
  4. ^ Bradbury, L E; Kansas G S, Levy S, Evans R L, Tedder T F (Nov. 1992). "The CD19/CD21 signal transducing complex of human B lymphocytes includes the target of antiproliferative antibody-1 and Leu-13 molecules". J. Immunol. (UNITED STATES) 149 (9): 2841–50. ISSN 0022-1767. PMID 1383329. 
  5. ^ Horváth, G; Serru V, Clay D, Billard M, Boucheix C, Rubinstein E (Nov. 1998). "CD19 is linked to the integrin-associated tetraspans CD9, CD81, and CD82". J. Biol. Chem. (UNITED STATES) 273 (46): 30537–43. doi:10.1074/jbc.273.46.30537. ISSN 0021-9258. PMID 9804823. 
  6. ^ Yefenof E, Klein G, Jondal M, Oldstone MB (June 1976). "Surface markers on human B and T-lymphocytes. IX. Two-color immunofluorescence studies on the association between ebv receptors and complement receptors on the surface of lymphoid cell lines". Int. J. Cancer 17 (6): 693–700. doi:10.1002/ijc.2910170602. PMID 181330. 
  7. ^ Leong, Anthony S-Y; Cooper, Kumarason; Leong, F Joel W-M (2003). Manual of Diagnostic Cytology (2 ed.). Greenwich Medical Media, Ltd.. pp. 93–94. ISBN 1-84110-100-1. 

Further reading

External links



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