[HTML][HTML] Enhanced detection of antigen-specific CD4+ T cells using altered peptide flanking residue peptide–MHC class II multimers

CJ Holland, G Dolton, M Scurr, K Ladell… - The Journal of …, 2015 - journals.aai.org
CJ Holland, G Dolton, M Scurr, K Ladell, AJ Schauenburg, K Miners, F Madura, AK Sewell
The Journal of Immunology, 2015journals.aai.org
Fluorochrome-conjugated peptide–MHC (pMHC) class I multimers are staple components of
the immunologist's toolbox, enabling reliable quantification and analysis of Ag-specific
CD8+ T cells irrespective of functional outputs. In contrast, widespread use of the equivalent
pMHC class II (pMHC-II) reagents has been hindered by intrinsically weaker TCR affinities
for pMHC-II, a lack of cooperative binding between the TCR and CD4 coreceptor, and a low
frequency of Ag-specific CD4+ T cell populations in the peripheral blood. In this study, we …
Abstract
Fluorochrome-conjugated peptide–MHC (pMHC) class I multimers are staple components of the immunologist’s toolbox, enabling reliable quantification and analysis of Ag-specific CD8+ T cells irrespective of functional outputs. In contrast, widespread use of the equivalent pMHC class II (pMHC-II) reagents has been hindered by intrinsically weaker TCR affinities for pMHC-II, a lack of cooperative binding between the TCR and CD4 coreceptor, and a low frequency of Ag-specific CD4+ T cell populations in the peripheral blood. In this study, we show that peptide flanking regions, extending beyond the central nonamer core of MHC-II–bound peptides, can enhance TCR–pMHC-II binding and T cell activation without loss of specificity. Consistent with these findings, pMHC-II multimers incorporating peptide flanking residue modifications proved superior for the ex vivo detection, characterization, and manipulation of Ag-specific CD4+ T cells, highlighting an unappreciated feature of TCR–pMHC-II interactions.
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