scholarly journals Activated T cells recruit exosomes secreted by dendritic cells via LFA-1

Blood ◽  
2009 ◽  
Vol 113 (9) ◽  
pp. 1977-1981 ◽  
Author(s):  
Esther N. M. Nolte-‘t Hoen ◽  
Sonja I. Buschow ◽  
Stephen M. Anderton ◽  
Willem Stoorvogel ◽  
Marca H. M. Wauben
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Membrane Proteins ◽  
Major Histocompatibility Complex Class ◽  
Class Ii ◽  
Complex Class ◽  
Extracellular Milieu ◽  
Histocompatibility Complex

Dendritic cells (DCs) are known to secrete exosomes that transfer membrane proteins, like major histocompatibility complex class II, to other DCs. Intercellular transfer of membrane proteins is also observed during cognate interactions between DCs and CD4+ T cells. The acquired proteins are functional and play a role in regulation of immune responses. How membrane protein transfer is achieved and regulated is unclear. Here we show that T cells can recruit major histocompatibility complex class II–containing DC exosomes secreted in the extracellular milieu during cognate DC–T-cell interactions. Recruitment of these exosomes required T-cell activation and was dependent on leukocyte function–associated antigen-1 (LFA-1) rather than on T-cell receptor specificity. Indeed, inducing a high-affinity state of LFA-1 on resting T cells was sufficient to provoke exosome binding. These results imply that DC exosomes secreted in the extracellular milieu during cognate T-cell–DC interactions are targeted to T cells activated in that microenvironment.

scholarly journals Selective enrichment of major histocompatibility complex class II-specific autoreactive T cells in the thymic Thy0 subset.

1993 ◽  
Vol 177 (5) ◽  
pp. 1429-1437 ◽  
Author(s):  
I Kariv ◽  
R R Hardy ◽  
K Hayakawa
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Major Histocompatibility Complex Class ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Complex Class ◽  
Autoreactive T Cells ◽  
Cell Hybrids ◽  
Histocompatibility Complex

We show here a unique enrichment of autoreactive T cells in the CD4+ mouse thymic subset, Thy0. A single- and 10-cell AMLR (autologous mixed leukocyte reaction) assay demonstrates that more than 30% (one cell per well) and almost all (10 cells per well) Thy0 cultures from normal mice exhibit reactivity specific to autologous cells, resulting in induction of interleukin 3 secretion. In contrast, no other mature thymic or splenic CD4+ T cell subsets showed such a high frequency. The majority of this AMLR reactivity in the Thy0 subset is accounted for by reactivity with self-major histocompatibility complex class II. Furthermore, antigenic selection in generating Thy0 subset is suggested by studies with T cell hybrids from a T cell receptor (TCR) V beta transgenic mouse line, 2B4 beta EH. TCR V-gene analysis of T cell hybrids revealed that those from Thy0, half of which responded to self-class II, consisted predominantly of cells that expressed endogenous TCR V beta s alone (without the transgene), unlike hybrids generated from peripheral naive T cells. Thus, we suggest that the presence of Thy0 results from selective stimulation of cells expressing TCR with sufficient affinity for autoantigens in the thymic CD4+ T cell repertoire.

scholarly journals Mycobacterium tuberculosis Synergizes with ATP To Induce Release of Microvesicles and Exosomes Containing Major Histocompatibility Complex Class II Molecules Capable of Antigen Presentation

2010 ◽  
Vol 78 (12) ◽  
pp. 5116-5125 ◽  
Author(s):  
Lakshmi Ramachandra ◽  
Yan Qu ◽  
Ying Wang ◽  
Colleen J. Lewis ◽  
Brian A. Cobb ◽  
...  
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Major Histocompatibility Complex Class ◽  
Class Ii ◽  
Hybridoma Cells ◽  
Complex Class ◽  
Mhc Ii ◽  
Histocompatibility Complex

ABSTRACT Major histocompatibility complex class II (MHC-II) molecules are released by murine macrophages upon lipopolysaccharide (LPS) stimulation and ATP signaling through the P2X7 receptor. These studies show that infection of macrophages with Mycobacterium tuberculosis or M. bovis strain BCG enhances MHC-II release in synergy with ATP. Shed MHC-II was contained in two distinct organelles, exosomes and plasma membrane-derived microvesicles, which were both able to present exogenous antigenic peptide to T hybridoma cells. Furthermore, microvesicles from mycobacterium-infected macrophages were able to directly present M. tuberculosis antigen (Ag) 85B(241-256)-I-Ab complexes that were generated by the processing of M. tuberculosis Ag 85B in infected cells to both M. tuberculosis-specific T hybridoma cells and naïve P25 M. tuberculosis T-cell receptor (TCR)-transgenic T cells. In the presence of prefixed macrophages, exosomes from mycobacterium-infected macrophages provided weak stimulation to M. tuberculosis-specific T hybridoma cells but not naïve P25 T cells. Thus, infection with M. tuberculosis primes macrophages for the increased release of exosomes and microvesicles bearing M. tuberculosis peptide-MHC-II complexes that may generate antimicrobial T-cell responses.

scholarly journals Antigen Presentation by Dendritic Cells after Immunization with DNA Encoding a Major Histocompatibility Complex Class II–restricted Viral Epitope

1997 ◽  
Vol 186 (9) ◽  
pp. 1481-1486 ◽  
Author(s):  
Sofia Casares ◽  
Kayo Inaba ◽  
Teodor-Doru Brumeanu ◽  
Ralph M. Steinman ◽  
Constantin A. Bona
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Antigen Presentation ◽  
Class Ii ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Dna Encoding ◽  
Histocompatibility Complex

Intramuscular and intracutaneous immunization with naked DNA can vaccinate animals to the encoded proteins, but the underlying mechanisms of antigen presentation are unclear. We used DNA that encodes an A/PR/8/34 influenza peptide for CD4 T cells and that elicits protective antiviral immunity. DNA-transfected, cultured muscle cells released the influenza polypeptide, which then could be presented on the major histocompatibility complex class II molecules of dendritic cells. When DNA was injected into muscles or skin, and antigen-presenting cells were isolated from either the draining lymph nodes or the skin, dendritic, but not B, cells presented antigen to T cells and carried plasmid DNA. We suggest that the uptake of DNA and/or the protein expressed by dendritic cells triggers immune responses to DNA vaccines.

scholarly journals Major histocompatibility complex class II-expressing endothelial cells induce allospecific nonresponsiveness in naive T cells.

1996 ◽  
Vol 183 (4) ◽  
pp. 1603-1612 ◽  
Author(s):  
F M Marelli-Berg ◽  
R E Hargreaves ◽  
P Carmichael ◽  
A Dorling ◽  
G Lombardi ◽  
...  
Keyword(s):  
T Cells ◽  
Endothelial Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Major Histocompatibility Complex Class ◽  
Class Ii ◽  
T Cell Response ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Histocompatibility Complex

The role of endothelial cells (EC) in initiating a primary T cell response is of importance in clinical transplantation and autoimmunity since EC are the first allogeneic target encountered by the recipient's immune system and may display tissue-specific autoantigens in the context of an inflammatory response. In this study, we have investigated the antigen-presenting cell function of human umbilical vein-derived EC (HUVEC), depleted of constitutively major histocompatibility complex class II+ cells and induced to express class II molecules by interferon-gamma. The results show that HUVEC do not express B7 but can support proliferation by antigen-specific T cell clones. In contrast, they were unable to initiate a primary alloresponse using three independent HUVEC cultures and MHC class II-mismatched CD4+ T cells from eight donors. The response to HUVEC was reconstituted by trans-costimulation provided by DAP.3 transfectants expressing human B7.1. Coculture of peripheral blood T cells with EC expressing allogeneic DR molecules had markedly different effects on CD45RO+ and RA+ subsets. Subsequent reactivity of the RO+ T cells was unaffected by exposure to EC, indicating a neutral encounter. In contrast, culture with DR+ EC induced allospecific nonresponsiveness in RA+ T cells.

scholarly journals Tetracycline-controllable Selection of CD4+ T Cells: Half-Life and Survival Signals in the Absence of Major Histocompatibility Complex Class II Molecules

2000 ◽  
Vol 191 (2) ◽  
pp. 355-364 ◽  
Author(s):  
Deborah Witherden ◽  
Nicolai van Oers ◽  
Caroline Waltzinger ◽  
Arthur Weiss ◽  
Christophe Benoist ◽  
...  
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Major Histocompatibility Complex Class ◽  
Half Life ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Complex Class ◽  
Histocompatibility Complex ◽  
Selection Of

A system that allows the study, in a gentle fashion, of the role of MHC molecules in naive T cell survival is described. Major histocompatibility complex class II–deficient mice were engineered to express Eα chains only in thymic epithelial cells in a tetracycline (tet)-controllable manner. This resulted in tet-responsive display of cell surface E complexes, positive selection of CD4+8– thymocytes, and generation of a CD4+ T cell compartment in a class II–barren periphery. Using this system, we have addressed two unresolved issues: the half-life of naive CD4+ T cells in the absence of class II molecules (3–4 wk) and the early signaling events associated with class II molecule engagement by naive CD4+ T cells (partial CD3 ζ chain phosphorylation and ZAP-70 association).

Studies on the Interaction of T-Cells with Major Histocompatibility Complex Class II Antigens

1997 ◽  
Vol 92 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Anthony N. Warrens
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Major Histocompatibility Complex Class ◽  
Class Ii ◽  
Stable Model ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Class Ii Antigens

1. Major histocompatibility complex class II antigens have the central role in the immune response of ‘presenting’ antigenic peptide to CD4+ T-cells. This interaction with a T-cell's receptor may result in activation, but, if recognition occurs without collateral molecular interactions which cause ‘co-stimulation’, these T-cells will be tolerized. 2. In the light of current interest in muscle cell transplantation, a transformed myoblast, TE671, phenotypically comparable to untransformed cells, transfected to express class II, was studied as a stable model of antigen presentation by muscle cells. These cells failed to activate T-cells but induced tolerance. 3. The DRα chain is unusual being the only non-polymorphic classical class II polypeptide, raising the question of its functional contribution. To this end, several single polypeptide constructs were generated with contributions from different class II α-chains. On this basis, it was established that DRα makes significant contributions to peptide binding and that its α2 domain is also important in T-cell recognition, possibly through CD4 binding. 4. One implication of the lack of polymorphism of DRα may be that it has a wider range of pairing partners, possibly including β chains of different isotypes. To address this, it is planned to use transfectants expressing only a mixed isotype pair to generate T-cell clones in vitro. These reagents would be useful tools to detect whether such mixed pairs exist physiologically. In this paper, the development of a system is described which will allow this question to be addressed.

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