Wooldridge, Linda, Clement, Mathew ![]() ![]() ![]() ![]() ![]() ![]() |
Abstract
CD8+ CTLs are essential for effective immune defense against intracellular microbes and neoplasia. CTLs recognize short peptide fragments presented in association with MHC class I (MHCI) molecules on the surface of infected or dysregulated cells. Ag recognition involves the binding of both TCR and CD8 coreceptor to a single ligand (peptide MHCI [pMHCI]). The TCR/pMHCI interaction confers Ag specificity, whereas the pMHCI/CD8 interaction mediates enhanced sensitivity to Ag. Striking biophysical differences exist between the TCR/pMHCI and pMHCI/CD8 interactions; indeed, the pMHCI/CD8 interaction can be >100-fold weaker than the cognate TCR/pMHCI interaction. In this study, we show that increasing the strength of the pMHCI/CD8 interaction by ∼15-fold results in nonspecific, cognate Ag-independent pMHCI tetramer binding at the cell surface. Furthermore, pMHCI molecules with superenhanced affinity for CD8 activate CTLs in the absence of a specific TCR/pMHCI interaction to elicit a full range of effector functions, including cytokine/chemokine release, degranulation and proliferation. Thus, the low solution binding affinity of the pMHCI/CD8 interaction is essential for the maintenance of CTL Ag specificity.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Medicine Systems Immunity Research Institute (SIURI) |
Subjects: | Q Science > QR Microbiology > QR180 Immunology R Medicine > RZ Other systems of medicine |
Publisher: | American Association of Immunologists |
ISSN: | 0022-1767 |
Last Modified: | 27 Jul 2023 01:07 |
URI: | https://orca.cardiff.ac.uk/id/eprint/24882 |
Citation Data
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