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CD8

Function: - identifies cytotoxic/suppressor T-cells that interact with MHC class I bearing targets - CD8 is thought to play a role in the process of T-cell mediated killing - signal is transduced by the associated tyrosine kinase lck - activation results in phospholipase activity (presumably PLC) Structure: - heterodimer of CD8-alpha & CD8-beta, linked by two disulfide bonds, or - heterodimer on thymocytes & as homodimer of CD8-alpha on peripheral blood T-lymphocytes Expression: - mature peripheral T cells ~25-35% - most cytotoxic T cells - CD4/CD8+ thymocytes - NK cells ~30% - cortical thymocytes ~70-80% Laboratory: - a marker for cytotoxic T cells, present on 30% of peripheral T cells

Interactions

molecular events

Related

CD4/CD8 ratio CD8 cells in blood cytotoxic (suppressor) T cell (CD8+, CTL)

General

cluster-of-differentiation antigen; cluster designation antigen; CD antigen cell surface receptor glycoprotein multisubunit protein

Properties

COMPARTMENT: plasma membrane CELL: T-cell MOTIF: ligand-binding site glycosylation site membrane region SUBUNITS: T-cell surface glycoprotein CD8 alpha chain MOTIF: signal sequence {1-21} immunoglobulin superfamily domain {22-135} MOTIF: cysteine residue {C43} MODIFICATION: cysteine residue {C115} cysteine residue {C115} MODIFICATION: cysteine residue {C43} transmembrane domain {183-203} T-cell surface glycoprotein CD8 beta chain MOTIF: signal sequence {1-21} immunoglobulin superfamily domain {22-132} MOTIF: cysteine residue {C41} MODIFICATION: cysteine residue {C116} N-glycosylation site {N102} cysteine residue {C116} MODIFICATION: cysteine residue {C41} transmembrane domain {171-191} Tyr phosphorylation site {Y209} MISC-INFO: LIGAND = MHC_CLASS_I_ANTIGEN

References

  1. Cotran et al Robbins Pathologic Basis of Disease, W.B. Saunders Co, Philadelphia, PA 1989 pg 165
  2. OMIM :accession 186730/186910
  3. http://www.pathologyoutlines.com/cdmarkers.html 15 October 2002
  4. Wikipedia; Note: CD8 entry http://en.wikipedia.org/wiki/CD8

Component-of

molecular complex

Components

CD8A; T-cell surface glycoprotein CD8 alpha chain; T-lymphocyte differentiation antigen T8/Leu-2 (MAL) CD8B; T-cell surface glycoprotein CD8 beta chain (CD8B1) T-cell surface glycoprotein CD8 beta-2 chain (CD8b pseudogene, CD8BP, CD8B2)

Databases & Figures

OMIM correlations Contents of Cytotoxic T-cell Granules