Cluster of Differentiation 86 (also known as CD86 and B7-2) is a protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 expressed on antigen-presenting cells that provides costimulatory signals necessary for T cell
T cell
T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in cell-mediated immunity. They can be distinguished from other lymphocytes, such as B cells and natural killer cells , by the presence of a T cell receptor on the cell surface. They are...

 activation and survival. It is the ligand
Ligand (biochemistry)
In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. In a narrower sense, it is a signal triggering molecule, binding to a site on a target protein.The binding occurs by intermolecular forces, such as ionic bonds, hydrogen...

 for two different proteins on the T cell surface: CD28
CD28 is one of the molecules expressed on T cells that provide co-stimulatory signals, which are required for T cell activation. CD28 is the receptor for CD80 and CD86 . When activated by Toll-like receptor ligands, the CD80 expression is upregulated in antigen presenting cells...

 (for autoregulation and intercellular association) and CTLA-4
CTLA4 also known as CD152 is a protein that plays an important regulatory role in the immune system...

 (for attenuation of regulation and cellular disassociation). CD86 works in tandem with CD80
Cluster of Differentiation 80 is a protein found on activated B cells and monocytes that provides a costimulatory signal necessary for T cell activation and survival...

 to prime T cells.

The CD86 gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 encodes a type I membrane protein that is a member of the immunoglobulin superfamily. Alternative splicing
Alternative splicing
Alternative splicing is a process by which the exons of the RNA produced by transcription of a gene are reconnected in multiple ways during RNA splicing...

 results in two transcript variants encoding different isoform
Protein isoform
A protein isoform is any of several different forms of the same protein. Different forms of a protein may be produced from related genes, or may arise from the same gene by alternative splicing. A large number of isoforms are caused by single-nucleotide polymorphisms or SNPs, small genetic...

s. Additional transcript variants have been described, but their full-length sequences have not been determined.

Clinical significance

CD86+ macrophage
Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...

s in Hodgkin lymphoma patients are an independent marker for potential nonresponse to firstline-therapy.

Further reading

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