Cd40

CD40

CD40 (pronounced "see-dee-forty") is a Costimulatory molecule that is present on Antigen presenting cells and is required for their activation. The binding of CD154 (CD40L) on T helper cells to CD40 activates the antigen presenting cells and induces a variety of downstream effects.

Etymology

CD40 is named for its identification as the "cluster of differentiation 40". The term "cluster of differentiation" is used in immunophenotyping to identify a Protein molecule present on the cell surface. CD40 was the 40th such molecule to be discovered and characterized.

Function

CD40 is a member of the Tumor necrosis factor receptor superfamily. It is expressed on B cells, Dendritic cells, Macrophages, Endothelial cells, and Epithelial cells. When activated by CD154 on T helper cells, CD40 induces a variety of responses in antigen presenting cells and other non-immune cells. These responses include the production of Cytokines and Chemokines, upregulation of costimulatory molecules, and increased cell survival and proliferation.

Clinical significance

Mutations in the CD40 gene can lead to Hyper IgM syndrome, a rare Primary immunodeficiency characterized by a lack of Immunoglobulin class switching. This results in an overproduction of Immunoglobulin M (IgM) and a lack of other types of immunoglobulins.

CD40 is also a target for Immunotherapy in cancer, as its activation can stimulate an immune response against tumor cells. Several drugs that target CD40 are currently in clinical trials.

Related terms

• CD154
• Costimulatory molecule
• Tumor necrosis factor receptor
• Hyper IgM syndrome
• Immunoglobulin class switching
• Immunotherapy

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