Single-cell analyses reveal two defects in peptide-specific activation of naive T cells from aged mice.
Confocal fluorescent microscopy was used to study redistribution of membrane-associated proteins in naive T cells from young and old mice from a transgenic stock whose T cells express a TCR specific for a peptide derived from pigeon cytochrome C. About 50% of the T cells from young mice that formed conjugates with peptide-pulsed APC were found to form complexes, at the site of binding to the APC, containing CD3epsilon, linker for activation of T cells (LAT), and Zap-70 in a central area and c-Cbl, p95(vav), Grb-2, PLC gamma, Fyn, and Lck distributed more uniformly across the interface area. Two-color staining showed that those cells that were able to relocalize c-Cbl, LAT, CD3epsilon, or PLC gamma typically relocalized all four of these components of the activation complex. About 75% of conjugates that rearranged LAT, c-Cbl, or PLC gamma also exhibited cytoplasmic NF-AT migration to the T cell nucleus. Aging had two effects. First, it led to a diminution of approximately 2-fold in the proportion of T cell/APC conjugates that could relocalize any of the nine tested proteins to the immune synapse. Second, aging diminished by approximately 2-fold the frequency of cytoplasmic NF-AT migration among cells that could generate immune synapses containing LAT, c-Cbl, or PLC gamma. Thus naive CD4 T cells from old mice exhibit at least two separable defects in the earliest stages of activation induced by peptide/MHC complexes.
Garcia
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GG
Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA.
Miller
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RA
D021581:Active Transport, Cell Nucleus / Q000235:genetics / Q000276:immunology; D000375:Aging / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D003593:Cytoplasm / Q000276:immunology / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D007399:Interphase / Q000235:genetics / Q000276:immunology; D018655:Lymphocyte Count; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010455:Peptides / Q000819:agonists / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology / Q000378:metabolism
D004268:DNA-Binding Proteins; D018984:Epitopes, T-Lymphocyte; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010455:Peptides; D014157:Transcription Factors