CD23

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FCER2
Protein FCER2 PDB 1t8c.png
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesFCER2, BLAST-2, CD23, CD23A, CLEC4J, FCE2, IGEBF, Fc fragment of IgE receptor II
External IDsOMIM: 151445 MGI: 95497 HomoloGene: 1517 GeneCards: FCER2
Gene location (Human)
Chromosome 19 (human)
Chr.Chromosome 19 (human)[1]
Chromosome 19 (human)
Genomic location for FCER2
Genomic location for FCER2
Band19p13.2Start7,688,758 bp[1]
End7,702,146 bp[1]
RNA expression pattern
PBB GE FCER2 206760 s at fs.png

PBB GE FCER2 206759 at fs.png
More reference expression data
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001207019
NM_001220500
NM_002002

RefSeq (protein)

NP_001193948
NP_001207429
NP_001993

Location (UCSC)Chr 19: 7.69 – 7.7 MbChr 8: 3.68 – 3.69 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

CD23, also known as Fc epsilon RII, or FcεRII, is the "low-affinity" receptor for IgE, an antibody isotype involved in allergy and resistance to parasites, and is important in regulation of IgE levels. Unlike many of the antibody receptors, CD23 is a C-type lectin, it is found on mature B cells, activated macrophages, eosinophils, follicular dendritic cells, and platelets.

There are two forms of CD23: CD23a and CD23b. CD23a is present on follicular B cells, whereas CD23b requires IL-4 to be expressed on T-cells, monocytes, Langerhans cells, eosinophils, and macrophages.[5]

Function[edit]

CD23 is known to have a role of transportation in antibody feedback regulation. Antigens which enter the blood stream can be captured by antigen specific IgE antibodies; the IgE immune complexes that are formed bind to CD23 molecules on B cells, and are transported to the B cell follicles of the spleen. The antigen is then transferred from CD23+ B cells to CD11c+ antigen presenting cells; the CD11c+ cells in turn present the antigen to CD4+ T cells, which can lead to an enhanced antibody response.[6]

Clinical significance[edit]

The allergen responsible in dust mite allergy Der p 1 is known to cleave CD23 from a cells surface; as CD23 is soluble, it can move freely and interact with cells in plasma. Recent studies have shown that increased levels of soluble CD23 cause the recruitment of non-sensitised B-cells in the presentation of antigen peptides to allergen-specific B-cells, therefore increasing the production of allergen specific IgE. IgE, in turn, is known to upregulate the cellular expression of CD23 and Fc epsilon RI (high-affinity IgE receptor).

In flow cytometry, CD23 is helpful in the differentiation of chronic lymphocytic leukemia (CD23-positive) from mantle cell lymphoma (CD23-negative).[7] CD23 can also be demonstrated in germinal centre B-cells using immunohistochemistry, but it is not present in the resting cells of the surrounding mantle zone. Lymphomas arising from the mantle zone are generally negative for CD23, but most B-cell chronic lymphomocytic leukaemias and low-grade B-cell lymphomas are positive, allowing immunohistochemistry to distinguish these conditions, which otherwise have a similar appearance. Reed–Sternberg cells are usually positive for CD23.[8]

See also[edit]

References[edit]

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000104921 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000005540 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Lichtman AH, Abbas AK (2003). Cellular and molecular immunology. Philadelphia: Saunders. pp. 324–325. ISBN 0-7216-0008-5.
  6. ^ Henningsson F, Ding Z, Dahlin JS, Linkevicius M, Carlsson F, Grönvik KO, Hallgren J, Heyman B (2011). Metzger DW (ed.). "IgE-mediated enhancement of CD4+ T cell responses in mice requires antigen presentation by CD11c+ cells and not by B cells". PLOS ONE. 6 (7): e21760. doi:10.1371/journal.pone.0021760. PMC 3130775. PMID 21765910.
  7. ^ Barna G, Reiniger L, Tátrai P, Kopper L, Matolcsy A (Sep 2008). "The cut-off levels of CD23 expression in the differential diagnosis of MCL and CLL". Hematological Oncology. 26 (3): 167–70. doi:10.1002/hon.855. PMID 18381689.
  8. ^ Cooper K, Leong AS (2003). Manual of diagnostic antibodies for immunohistology. London: Greenwich Medical Media. p. 95. ISBN 1-84110-100-1.

Further reading[edit]

External links[edit]

  • Human FCER2 genome location and FCER2 gene details page in the UCSC Genome Browser.
  • PDBe-KB provides an overview of all the structure information available in the PDB for Human Low affinity immunoglobulin epsilon Fc receptor