CD5 (protein)

CD5
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2JA4, 2JOP, 2JP0, 2OTT
Identifiers
Aliases	CD5, LEU1, T1, CD5 molecule
External IDs	OMIM: 153340; MGI: 88340; HomoloGene: 7260; GeneCards: CD5; OMA:CD5 - orthologs
Gene location (Human) Chr. Chromosome 11 (human)[1] Band 11q12.2 Start 61,102,489 bp[1] End 61,127,852 bp[1]
Gene location (Mouse) Chr. Chromosome 19 (mouse)[2] Band 19 A|19 7.16 cM Start 10,694,480 bp[2] End 10,716,366 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in granulocyte lymph node blood appendix tonsil testicle spleen bone marrow cells gallbladder thymus Top expressed in thymus mesenteric lymph nodes blood embryo spleen secondary oocyte primary oocyte esophagus embryo lip More reference expression data BioGPS More reference expression data
Gene ontology Molecular function scavenger receptor activity protein binding transmembrane signaling receptor activity signaling receptor activity Cellular component integral component of membrane plasma membrane integral component of plasma membrane membrane external side of plasma membrane Biological process apoptotic signaling pathway T cell costimulation cell population proliferation cell recognition receptor-mediated endocytosis vesicle-mediated transport endocytosis Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 921 12507 Ensembl ENSG00000110448 ENSMUSG00000024669 UniProt P06127 P13379 RefSeq (mRNA) NM_014207 NM_001346456 NM_007650 RefSeq (protein) NP_001333385 NP_055022 NP_031676 Location (UCSC) Chr 11: 61.1 – 61.13 Mb Chr 19: 10.69 – 10.72 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

CD5^[5] is a cluster of differentiation expressed on the surface of T cells (various species) and in a subset of murine B cells known as B-1a. The expression of this receptor in human B cells has been a controversial topic and to date there is no consensus regarding the role of this receptor as a marker of human B cells. B-1 cells have limited diversity of their B-cell receptor due to their lack of the enzyme terminal deoxynucleotidyl transferase (TdT) and are potentially self-reactive. CD5 serves to mitigate activating signals from the BCR so that the B-1 cells can only be activated by very strong stimuli (such as bacterial proteins) and not by normal tissue proteins. CD5 was used as a T-cell marker until monoclonal antibodies against CD3 were developed.

In humans, the gene is located on the long arm of chromosome 11. There is no confirmed ligand for CD5 but there is evidence that CD72, a C-type lectin, may be a ligand or that CD5 may be homophilic, binding CD5 on the surface of other cells.^[6] CD5 includes a scavenger receptor cysteine-rich protein domain.

T cells express higher levels of CD5 than B cells. CD5 is upregulated on T cells upon strong activation. In the thymus, there is a correlation with CD5 expression and strength of the interaction of the T cell towards self-peptides.

CD5 is a good immunohistochemical marker for T-cells, although not as sensitive as CD3. About 76% of T-cell neoplasms are reported to express CD5, and it is also found in chronic lymphocytic leukemia and mantle cell lymphoma (both being B cell malignancies), that do not express CD3. It is commonly lost in cutaneous T-cell lymphoma, and its absence can be used as an indicator of malignancy in this condition. The absence of CD5 in T cell acute lymphoblastic leukemia, while relatively rare, is associated with a poor prognosis.^{[7]: 67–69}

• CD5+Antigen at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
• Human CD5 genome location and CD5 gene details page in the UCSC Genome Browser.

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