title: Inhibition of T cell receptor-coreceptor interactions by antagonist ligands visualized by live FRET imaging of the T-hybridoma immunological synapse.
abstract: The diverse effects of TCR agonists and antagonists on T cell activation are believed to be modified by the differential recruitment of CD4 or CD8 coreceptors to the TCR-MHCp complex. We used three-dimensional live cell imaging of fluorescence resonance energy transfer (FRET) between CD3zeta and CD4 fused to variants of the green fluorescent protein to investigate TCR-CD4 interactions during T cell activation. We demonstrate that recognition of agonist MHCp complexes triggers intermolecular interaction between CD4 and TCR, detectable across the T-hybridoma-APC contact area. This interaction is blocked by the presence of antagonist ligands without decreasing the recruitment of zeta and CD4 or preventing their partial colocalization in the immunological synapse.
authors.affiliation: Deptartment of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Zal
authors.forename: M Anna
authors.initials: MA
authors.lastname: Zal
authors.forename: Nicholas R J
authors.initials: NR
authors.lastname: Gascoigne
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D017252:CD3 Complex / Q000235:genetics / Q000276:immunology*; D015704:CD4 Antigens / Q000235:genetics / Q000276:immunology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006801:Humans; D006825:Hybridomas; D007091:Image Processing, Computer-Assisted; D007202:Indicators and Reagents; D008024:Ligands; D008164:Luminescent Proteins / Q000235:genetics / Q000276:immunology; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D013050:Spectrometry, Fluorescence / Q000379:methods; D013569:Synapses / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: C108123:4-amino-5-(4-methylphenyl)-7-(tert-butyl)pyrazolo(3,4-d)pyrimidine; D001426:Bacterial Proteins; D017252:CD3 Complex; C121704:CD3 antigen, zeta chain; D015704:CD4 Antigens; D004791:Enzyme Inhibitors; D007202:Indicators and Reagents; D008024:Ligands; D008164:Luminescent Proteins; D011720:Pyrazoles; D011743:Pyrimidines; D011993:Recombinant Fusion Proteins; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins