CD 86

CD is the acronym for the term "Cluster of Differentiation". "CD" refers to groups of cellular surface features that have been classified according to biochemical or functional criteria. The CD classification enables comprehensible transparency in immunohistological and immunological diagnostics. Currently > 400 cluster molecules are defined and assigned. The protein name is not always identical to the gene name (e.g. CD4 - clone 1F6; CD8 - clone DK25).

The CD molecules are mainly membrane-bound glycoproteins. Some of these are expressed in a cell-specific manner. Their detection can therefore have a high diagnostic value in neoplastic and inflammatory processes. Some of the proteins included in the CD classification have receptor or signaling functions, while others exert enzymatic activities or are part of intercellular communication.

CD 86 acts as a ligand for CD28 and CTLA-4 on T cells. Binding to CD 28 provides the "second signal" for the activation of naïve T cells and their proliferation and cytokine production.

CD 86 also binds to CTLA-4 and this binding inhibits T cell activation (negative feedback). There is evidence of interaction with CD80 (B7-1): Both molecules fulfill similar tasks, but differ in expression dynamics and affinity.

Autoimmune diseases: Excessive CD86-mediated co-stimulation promotes pathological T cell activity. Therapeutic target: The drugs Abatacept/Belatacept are CTLA-4-Ig fusion proteins that bind to CD80/CD86 and thus block co-stimulation. The preparations are used, for example, in rheumatoid arthritis, psoriatic arthritis and organ transplants.