Abstract
Using a chemically homogeneous radiolabeled peptide of high specific activity (125I-QLSPYPFDL, 3.5 x 10(18) cpm per mole) we show that at a peptide concentration (5 pM) causing half-maximal lysis of target cells by a cytolytic T lymphocyte (CTL) clone that recognizes the peptide in association with Ld, a class I MHC protein, only 3 peptide molecules on average are bound by Ld per target cell. From the distribution of Ld on the target cells, we suggest that a single peptide-MHC complex per target cell can trigger activation of the T cell cytolytic response.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Clone Cells
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Cytotoxicity Tests, Immunologic
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Cytotoxicity, Immunologic* / drug effects
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Epitopes / chemistry
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Epitopes / metabolism
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H-2 Antigens / immunology
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HLA-A2 Antigen / immunology
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Histocompatibility Antigens / immunology*
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Humans
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Kinetics
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Mice
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Molecular Sequence Data
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Peptide Fragments / immunology*
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Peptide Fragments / pharmacology
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Protein Binding / immunology
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T-Lymphocytes, Cytotoxic / drug effects
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T-Lymphocytes, Cytotoxic / immunology*
Substances
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Epitopes
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H-2 Antigens
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HLA-A2 Antigen
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Histocompatibility Antigens
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Peptide Fragments