CD8+ T-cells are fundamental in the success of removal of viral infections and tumours in an adaptive immune response. These T-cells express a cell surface glycoprotein co-receptor CD8. The CD8 co-receptor exists in either a homo or herterodimeric form (alpha/alpha or alpha/beta respectively) (Gao et al 2000). CD8+ T-cell recognition is mediated through the T-cell receptor (TCR), binding to the peptide binding platform of the major hiscompatability complex (pMHCI) (Laugel et al 2007). CD8 binds to invariant regions of pMHCI, at a different site but simultaneously to that of the TCR, recognising short peptide sequences 8-11 amino acid sequences in length. (Wooldridge et al 2006).
CD8 has been implicated with a range of different functions. It is known to stabilise the TCR/pMHCI interaction. CD8 is involved in TCR mediated cell signalling by binding to protein kinases which are involved with the phosphorylation of CD3. This then mediates the recruitment of TCR/CD3/pMHCI to lipid rafts which are preferential sites for cell signalling. (Wooldridge et al 2007).
CD8 plays an important role in CD8+ T-cell activation. Here we want to study this co-receptor as it has vital implications in how T-cells respond to cancerous and virally infected cells and therefore the success of the immune system to keep our bodies healthy.