Document Detail


Kinetics of MHC-antigen complex formation on antigen-presenting cells.
MedLine Citation:
PMID:  2453565     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
With the use of flow cytometry, we recorded changes in intracellular ionized calcium [Ca2+]i of Indo-1 loaded T cells that were triggered by contact with APC. This rapid readout of TCR perturbation enabled us to monitor the formation of stimulatory Ag-MHC complexes on EBV-transformed B cells that were either pulsed with native tetanus toxoid (TT) or with a 12-amino-acid fragment of this protein. Neither unpulsed APC nor Ag-specific APC that were pulsed with native Ag and kept at +4 degrees C were able to induce changes in basal T cell [Ca2+]i in TT-specific T cell clones. After 1 h at 37 degrees C, however, the Ag-pulsed APC were able to induce a three-to-fourfold increase in [Ca2+]i. This length of time appeared to be almost independent of the concentration of Ag with which the APC were pulsed, suggesting that the lag time was due more to intracellular transit than to association of the processed Ag with the MHC molecule. Furthermore, the same lag time and independence of Ag concentration were found when the EBV-transformed B cells were pulsed with a mouse-anti-transferrin receptor mAb and tested for their capacity to trigger a T cell clone specific for processed mouse Ig. This indicates that, in addition to surface Ig, other receptors that are internalized can function in the same fashion in the uptake and processing of a soluble Ag. In contrast to what was found with intact native Ag, no lag time was observed when the APC were pulsed with high concentrations of a 12-amino-acid peptide, containing the amino acid sequence recognized by a TT-specific T cell clone, suggesting that the formation of MHC-peptide complexes occurs instantly. Pulsing with a lower peptide concentration, however, caused the appearance of a time-dependent increase in efficacy of Ag presentation, suggesting a slow accumulation of MHC-peptide complexes on the B cell membrane.
Authors:
E Roosnek; S Demotz; G Corradin; A Lanzavecchia
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of immunology (Baltimore, Md. : 1950)     Volume:  140     ISSN:  0022-1767     ISO Abbreviation:  J. Immunol.     Publication Date:  1988 Jun 
Date Detail:
Created Date:  1988-07-12     Completed Date:  1988-07-12     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985117R     Medline TA:  J Immunol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  4079-82     Citation Subset:  AIM; IM    
Affiliation:
Basel Institute for Immunology, Switzerland.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antigen-Presenting Cells / immunology,  metabolism*
Calcium / metabolism
Clone Cells / immunology,  metabolism
Epitopes / immunology
HLA-D Antigens / metabolism*
Humans
Intracellular Fluid / metabolism
Kinetics
Lymphocyte Activation
Macromolecular Substances
Mice
Oligopeptides / immunology
Receptors, Transferrin / physiology
T-Lymphocytes / immunology,  metabolism*
Tetanus Toxoid / immunology
Transferrin / metabolism
Chemical
Reg. No./Substance:
0/Epitopes; 0/HLA-D Antigens; 0/Macromolecular Substances; 0/Oligopeptides; 0/Receptors, Transferrin; 0/Tetanus Toxoid; 11096-37-0/Transferrin; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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