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.

CD5
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesCD5, LEU1, T1, CD5 molecule
External IDsOMIM: 153340 MGI: 88340 HomoloGene: 7260 GeneCards: CD5
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

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.

Immunohistochemistry edit

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

References edit

  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, Marion H.; Lacey, Erica (15 November 2010). "A ligand for CD5 is CD5". Journal of Immunology. 185 (10): 6068–74. doi:10.4049/jimmunol.0903823. eISSN 1550-6606. ISSN 0022-1767. LCCN 52052893. OCLC 1778718. PMC 2996635. PMID 20952682.
  7. ^ Leong, Anthony S-Y; Cooper, Kumarason; Leong, F Joel W-M (1 December 2002). "Section 1 - Antibodies (CD 5)". Manual of Diagnostic Antibodies for Immunohistology (Second ed.). Greenwich Medical Media. pp. 67–69. ISBN 978-1841101002. OCLC 51439459. OL 8917797M. Retrieved 22 December 2022 – via Internet Archive.

Further reading edit

External links edit