CD5 (protein)

CD5
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesCD5, LEU1, T1, CD5 molecule
External IDsOMIM: 153340; MGI: 88340; HomoloGene: 7260; GeneCards: CD5; OMA:CD5 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_014207
NM_001346456

NM_007650

RefSeq (protein)

NP_001333385
NP_055022

NP_031676

Location (UCSC)Chr 11: 61.1 – 61.13 MbChr 19: 10.69 – 10.72 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/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.

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000110448Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000024669Ensembl, 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. ^ "Entrez Gene: CD5 CD5 molecule".
  6. ^ Brown MH, Lacey E (November 2010). "A ligand for CD5 is CD5". Journal of Immunology. 185 (10): 6068–6074. doi:10.4049/jimmunol.0903823. eISSN 1550-6606. LCCN 52052893. OCLC 1778718. PMC 2996635. PMID 20952682.