Abstract
We have developed a single-molecule imaging technique that uses quantum-dot-labeled peptide-major histocompatibility complex (pMHC) ligands to study CD4(+) T cell functional sensitivity. We found that naive T cells, T cell blasts, and memory T cells could all be triggered by a single pMHC to secrete tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) cytokines with a rate of ∼1,000, ∼10,000, and ∼10,000 molecules/min, respectively, and that additional pMHCs did not augment secretion, indicating a digital response pattern. We also found that a single pMHC localized to the immunological synapse induced the slow formation of a long-lasting T cell receptor (TCR) cluster, consistent with a serial engagement mechanism. These data show that scaling up CD4(+) T cell cytokine responses involves increasingly efficient T cell recruitment rather than greater cytokine production per cell.
Copyright © 2013 Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Video-Audio Media
MeSH terms
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Adaptive Immunity
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Amino Acid Sequence
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Animals
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Antigen Presentation
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Biotinylation
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CD4-Positive T-Lymphocytes / drug effects
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CD4-Positive T-Lymphocytes / immunology
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CD4-Positive T-Lymphocytes / metabolism*
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Cell Differentiation
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Histocompatibility Antigens Class II / immunology*
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Immunoconjugates
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Immunologic Memory
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Immunological Synapses
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Interleukin-2 / metabolism
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Lymphocyte Activation
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Molecular Sequence Data
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Moths
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Peptide Fragments / immunology
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Quantum Dots
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Receptors, Antigen, T-Cell, alpha-beta / immunology
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Secretory Rate
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Single-Cell Analysis
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T-Lymphocyte Subsets / drug effects
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T-Lymphocyte Subsets / immunology
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T-Lymphocyte Subsets / metabolism*
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Tumor Necrosis Factor-alpha / metabolism
Substances
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Histocompatibility Antigens Class II
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I-E-antigen
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Immunoconjugates
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Interleukin-2
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Peptide Fragments
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Receptors, Antigen, T-Cell, alpha-beta
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Tumor Necrosis Factor-alpha