Abstract
Proteolysis of the invariant chain (li) leads to the generation of abundant MHC class II-associated invariant chain peptides (CLIP), which bind in the MHC class II binding groove via supermotifs in a manner similar to that of antigenic peptides. We have engineered an li vector with the capacity to express any antigenic peptide of interest instead of CLIP, for T cell stimulation. When peripheral blood mononuclear cells (PBMC) were pulsed with li hybrids encoding T cell epitopes of tetanus toxin or acetylcholine receptor, stimulation of T cells was dramatically enhanced compared to stimulation after priming with either the native or recombinant proteins. Site-specific insertion of antigenic sequences into the CLIP region promoted enhanced antigenicity of li hybrids which were shown to be processed intracellularly in a chloroquine-sensitive compartment. Naturally processed T helper epitopes were visualized directly on the surface of PBMC and identified as analogs of CLIP associated with MHC class II molecules. This novel li vector provides a flexible and efficient system for the delivery of defined peptide epitopes to T cells which might be useful in the development of specific vaccines and in the study of intracellular processing.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Antigen Presentation / genetics*
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Antigens, Differentiation, B-Lymphocyte / genetics*
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Antigens, Differentiation, B-Lymphocyte / immunology
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Antigens, Differentiation, B-Lymphocyte / metabolism
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Epitopes, T-Lymphocyte / genetics*
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Epitopes, T-Lymphocyte / immunology
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Epitopes, T-Lymphocyte / metabolism
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Genetic Vectors / chemical synthesis
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Genetic Vectors / immunology*
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HLA-DR4 Antigen / metabolism
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Histocompatibility Antigens Class I / metabolism
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Histocompatibility Antigens Class II / genetics*
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Histocompatibility Antigens Class II / immunology
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Histocompatibility Antigens Class II / metabolism
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Humans
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Intracellular Fluid / metabolism
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Lymphocyte Activation
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Molecular Sequence Data
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Protein Binding / genetics
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Protein Engineering
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Receptors, Cholinergic / genetics
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Receptors, Cholinergic / immunology
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Recombinant Fusion Proteins / immunology
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Recombinant Fusion Proteins / metabolism
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T-Lymphocytes / immunology
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T-Lymphocytes / metabolism
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Tetanus Toxin / genetics
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Tetanus Toxin / immunology
Substances
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Antigens, Differentiation, B-Lymphocyte
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Epitopes, T-Lymphocyte
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HLA-DR4 Antigen
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Histocompatibility Antigens Class I
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Histocompatibility Antigens Class II
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Receptors, Cholinergic
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Recombinant Fusion Proteins
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Tetanus Toxin
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invariant chain