title: Ca2+ release from the endoplasmic reticulum of NY-ESO-1-specific T cells is modulated by the affinity of TCR and by the use of the CD8 coreceptor.
abstract: Although several cancer immunotherapy strategies are based on the use of analog peptides and on the modulation of the TCR affinity of adoptively transferred T cells, it remains unclear whether tumor-specific T cell activation by strong and weak TCR stimuli evoke different Ca(2+) signatures from the Ca(2+) intracellular stores and whether the amplitude of Ca(2+) release from the endoplasmic reticulum (ER) can be further modulated by coreceptor binding to peptide/MHC. In this study, we combined functional, structural, and kinetic measurements to correlate the intensity of Ca(2+) signals triggered by the stimulation of the 1G4 T cell clone specific to the tumor epitope NY-ESO-1(157-165). Two analogs of the NY-ESO-1(157-165) peptide, having similar affinity to HLA-A2 molecules, but a 6-fold difference in binding affinity for the 1G4 TCR, resulted in different Ca(2+) signals and T cell activation. 1G4 stimulation by the stronger stimulus emptied the ER of stored Ca(2+), even in the absence of CD8 binding, resulting in sustained Ca(2+) influx. In contrast, the weaker stimulus induced only partial emptying of stored Ca(2+), resulting in significantly diminished and oscillatory Ca(2+) signals, which were enhanced by CD8 binding. Our data define the range of TCR/peptide MHC affinities required to induce depletion of Ca(2+) from intracellular stores and provide insights into the ability of T cells to tailor the use of the CD8 coreceptor to enhance Ca(2+) release from the ER. This, in turn, modulates Ca(2+) influx from the extracellular environment, ultimately controlling T cell activation.
authors.affiliation: Weatherall Institute of Molecular Medicine, OX3 9DS, Oxford.
authors.forename: Ji-Li
authors.initials: JL
authors.lastname: Chen
authors.affiliation: Dept of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Morgan
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Stewart-Jones
authors.affiliation: Weatherall Institute of Molecular Medicine, OX3 9DS, Oxford.
authors.forename: Dawn
authors.initials: D
authors.lastname: Shepherd
authors.affiliation: Immunocore, Limited, 57c Milton Park, Abingdon, Oxon, OX14 4RX, UK.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Bossi
authors.affiliation: Dept of Infection, Immunity and Biochemistry, The Henry Wellcome Building, Cardiff University School of Medicine, Cardiff, CF14 4XN.
authors.forename: Linda
authors.initials: L
authors.lastname: Wooldridge
authors.affiliation: Weatherall Institute of Molecular Medicine, OX3 9DS, Oxford.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Hutchinson
authors.affiliation: Dept of Infection, Immunity and Biochemistry, The Henry Wellcome Building, Cardiff University School of Medicine, Cardiff, CF14 4XN.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Sewell
authors.affiliation: Cambridge Institute for Medical Research, PO Box 139, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, UK.
authors.forename: Gillian M
authors.initials: GM
authors.lastname: Griffiths
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
authors.forename: P Anton
authors.initials: PA
authors.lastname: van der Merwe
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
authors.forename: E Yvonne
authors.initials: EY
authors.lastname: Jones
authors.affiliation: Dept of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
authors.forename: Antony
authors.initials: A
authors.lastname: Galione
authors.affiliation: Weatherall Institute of Molecular Medicine, OX3 9DS, Oxford.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cerundolo
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002999:Clone Cells; D018360:Crystallography, X-Ray; D003594:Cytoplasmic Granules / Q000276:immunology / Q000378:metabolism; D003601:Cytotoxicity Tests, Immunologic; D004721:Endoplasmic Reticulum / Q000276:immunology / Q000378:metabolism*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D009363:Neoplasm Proteins / Q000276:immunology* / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D020033:Protein Isoforms / Q000276:immunology / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism* / Q000502:physiology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism*
chemical_list: C067361:CD8 receptor; D018984:Epitopes, T-Lymphocyte; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D020033:Protein Isoforms; D011948:Receptors, Antigen, T-Cell; C504237:peptide NY-ESO-1 157-165; D002118:Calcium