CD154

CD40 ligand (TNF superfamily, member 5, hyper-IgM syndrome)
PDB rendering based on 1aly.
Available structures PDB Ortholog search: Template:Homologene2PDBe PDBe, Template:Homologene2uniprot RCSB List of PDB id codes 1aly​, 1i9r​
Identifiers
Symbols	CD40LG ; TRAP; CD154; CD40L; HIGM1; IGM; IMD3; T-BAM; TNFSF5; gp39; hCD40L
External IDs	Template:OMIM5 Template:MGI HomoloGene: 56
Gene ontology Molecular function Template:GNF GO Template:GNF GO Template:GNF GO Cellular component Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Biological process Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO Template:GNF GO
RNA expression pattern
More reference expression data
Orthologs
Template:GNF Ortholog box
Species	Human	Mouse
Entrez	n/a	n/a
Ensembl	n/a	n/a
UniProt	n/a	n/a
RefSeq (mRNA)	n/a	n/a
RefSeq (protein)	n/a	n/a
Location (UCSC)	n/a	n/a
PubMed search	n/a	n/a

CD154, also called CD40 ligand or CD40L, is a protein that is primarily expressed on activated T cells and is a member of the TNF family of molecules. It binds to CD40 on antigen-presenting cells (APC), which leads to many effects depending on the target cell type. In general, CD40L plays the role of a costimulatory molecule and induces activation in APC in association with T cell receptor stimulation by MHC molecules on the APC. The protein encoded by this gene is expressed on the surface of T cells. It regulates B cell function by engaging CD40 on the B cell surface. A defect in this gene results in an inability to undergo immunoglobulin class switch and is associated with hyper-IgM syndrome.

Expression of CD154

CD40 ligand is primarily expressed on activated CD4+ T lymphocytes but is also found in a soluble form. While CD40L was originally described on T lymphocytes, its expression has since been found on a wide variety of cells, including platelets, mast cells, macrophages, basophils, NK cells, B lymphocytes, as well as non-haematopoietic cells (smooth muscle cells, endothelial cells, and epithelial cells)[1].

Specific effects on cells

Macrophages

In the macrophage, the primary signal for activation is IFN-γ from Th1 type CD4 T cells. The secondary signal is CD40L on the T cell, which binds CD40 on the macrophage cell surface. As a result, the macrophage expresses more CD40 and TNF receptors on its surface, which helps increase the level of activation. The activated macrophage can then destroy phagocytosed bacteria and produce more cytokines.

B cells

The B cell can present antigens to helper T cells. If the T cell recognizes the peptide presented by the B cell, the T cell synthesizes CD40L. The CD40L binds to the B cell's CD40 receptor, causing resting B cell activation. The T cell also produces IL-4, which directly binds to B cell receptors. As a result of this interaction, the B cell can undergo division, antibody isotype switching, and differentiation to plasma cells. The end-result is a B cell that is able to mass-produce specific antibodies against an antigenic target.

References

• Parham, Peter (2004). The Immune System (2nd Ed ed.). Garland Science. pp. 169–173. ISBN 0-8153-4093-1.CS1 maint: Extra text (link)

Further reading

• Tong AW, Stone MJ (1997). "CD40 and the effect of anti-CD40-binding on human multiple myeloma clonogenicity". Leuk. Lymphoma. 21 (1–2): 1–8. PMID 8907262.
• van Kooten C, Banchereau J (2000). "CD40-CD40 ligand". J. Leukoc. Biol. 67 (1): 2–17. PMID 10647992.
• Schattner EJ (2003). "CD40 ligand in CLL pathogenesis and therapy". Leuk. Lymphoma. 37 (5–6): 461–72. PMID 11042507.
• Bhushan A, Covey LR (2002). "CD40:CD40L interactions in X-linked and non-X-linked hyper-IgM syndromes". Immunol. Res. 24 (3): 311–24. PMID 11817328.
• Cheng G, Schoenberger SP (2002). "CD40 signaling and autoimmunity". Curr. Dir. Autoimmun. 5: 51–61. PMID 11826760.
• Subauste CS (2002). "CD154 and type-1 cytokine response: from hyper IgM syndrome to human immunodeficiency virus infection". J. Infect. Dis. 185 Suppl 1: S83–9. PMID 11865444.
• Kornbluth RS (2003). "An expanding role for CD40L and other tumor necrosis factor superfamily ligands in HIV infection". J. Hematother. Stem Cell Res. 11 (5): 787–801. doi:10.1089/152581602760404595. PMID 12427285.
• Xu Y, Song G (2005). "The role of CD40-CD154 interaction in cell immunoregulation". J. Biomed. Sci. 11 (4): 426–38. doi:10.1159/000077892. PMID 15153777.

External links

• CD154+Antigen at the US National Library of Medicine Medical Subject Headings (MeSH)