Inhibition of T cell response with peptides is influenced by both peptide-binding specificity of major histocompatibility complex molecules and susceptibility of T cells to blocking

1989 ◽  
Vol 19 (6) ◽  
pp. 1071-1077 ◽  
Author(s):  
Paul V. Lehmann ◽  
Francis Cardinaux ◽  
Ettore Appella ◽  
Simone Muller ◽  
Fiorenza Falcioni ◽  
...  
2008 ◽  
Vol 82 (10) ◽  
pp. 4697-4705 ◽  
Author(s):  
Nicolas P. Andrews ◽  
Christopher D. Pack ◽  
Aron E. Lukacher

ABSTRACT The CD8 coreceptor is important for positive selection of major histocompatibility complex I (MHC-I)-restricted thymocytes and in the generation of pathogen-specific T cells. However, the requirement for CD8 in these processes may not be essential. We previously showed that mice lacking β2-microglobulin are highly susceptible to tumors induced by mouse polyoma virus (PyV), but CD8-deficient mice are resistant to these tumors. In this study, we show that CD8-deficient mice also control persistent PyV infection as efficiently as wild-type mice and generate a substantial virus-specific, MHC-I-restricted, T-cell response. Infection with vesicular stomatitis virus (VSV), which is acutely cleared, also recruited antigen-specific, MHC-I-restricted T cells in CD8-deficient mice. Yet, unlike in VSV infection, the antiviral MHC-I-restricted T-cell response to PyV has a prolonged expansion phase, indicating a requirement for persistent infection in driving T-cell inflation in CD8-deficient mice. Finally, we show that the PyV-specific, MHC-I-restricted T cells in CD8-deficient mice, while maintained long term at near-wild-type levels, are short lived in vivo and have extremely narrow T-cell receptor repertoires. These findings provide a possible explanation for the resistance of CD8-deficient mice to PyV-induced tumors and have implications for the maintenance of virus-specific MHC-I-restricted T cells during persistent infection.


2000 ◽  
Vol 191 (5) ◽  
pp. 805-812 ◽  
Author(s):  
Reinhard Obst ◽  
Nikolai Netuschil ◽  
Karsten Klopfer ◽  
Stefan Stevanović ◽  
Hans-Georg Rammensee

By analyzing T cell responses against foreign major histocompatibility complex (MHC) molecules loaded with peptide libraries and defined self- and viral peptides, we demonstrate a profound influence of self-MHC molecules on the repertoire of alloreactive T cells: the closer the foreign MHC molecule is related to the T cell's MHC, the higher is the proportion of peptide-specific, alloreactive (“allorestricted”) T cells versus T cells recognizing the foreign MHC molecule without regard to the peptide in the groove. Thus, the peptide repertoire of alloreactive T cells must be influenced by self-MHC molecules during positive or negative thymic selection or peripheral survival, much like the repertoire of the self-restricted T cells. In consequence, allorestricted, peptide-specific T cells (that are of interest for clinical applications) are easier to obtain if T cells and target cells express related MHC molecules.


2007 ◽  
Vol 75 (11) ◽  
pp. 5200-5209 ◽  
Author(s):  
Florence Dzierszinski ◽  
Marion Pepper ◽  
Jason S. Stumhofer ◽  
David F. LaRosa ◽  
Emma H. Wilson ◽  
...  

ABSTRACT Challenge with the intracellular protozoan parasite Toxoplasma gondii induces a potent CD8+ T-cell response that is required for resistance to infection, but many questions remain about the factors that regulate the presentation of major histocompatibility complex class I (MHC-I)-restricted parasite antigens and about the role of professional and nonprofessional accessory cells. In order to address these issues, transgenic parasites expressing ovalbumin (OVA), reagents that track OVA/MHC-I presentation, and OVA-specific CD8+ T cells were exploited to compare the abilities of different infected cell types to stimulate CD8+ T cells and to define the factors that contribute to antigen processing. These studies reveal that a variety of infected cell types, including hematopoietic and nonhematopoietic cells, are capable of activating an OVA-specific CD8+ T-cell hybridoma, and that this phenomenon is dependent on the transporter associated with antigen processing and requires live T. gondii. Several experimental approaches indicate that T-cell activation is a consequence of direct presentation by infected host cells rather than cross-presentation. Surprisingly, nonprofessional antigen-presenting cells (APCs) were at least as efficient as dendritic cells at activating this MHC-I-restricted response. Studies to assess whether these cells are involved in initiation of the CD8+ T-cell response to T. gondii in vivo show that chimeric mice expressing MHC-I only in nonhematopoietic compartments are able to activate OVA-specific CD8+ T cells upon challenge. These findings associate nonprofessional APCs with the initial activation of CD8+ T cells during toxoplasmosis.


1997 ◽  
Vol 186 (6) ◽  
pp. 899-908 ◽  
Author(s):  
Silvia Corinti ◽  
Raffaele De Palma ◽  
Angelo Fontana ◽  
Maria Cristina Gagliardi ◽  
Carlo Pini ◽  
...  

We have isolated CD8+ α/β T cells from the blood of atopic and healthy individuals which recognize a nonpeptide antigen present in an allergenic extract from Parietaria judaica pollen. This antigen appears to be a carbohydrate because it is resistant to proteinase K and alkaline digestion, is hydrophilic, and is sensitive to trifluoromethane-sulphonic and periodic acids. In addition, on a reverse-phase high performance liquid chromatography column the antigen recognized by CD8+ T cells separates in a fraction which contains >80% hexoses (glucose and galactose) and undetectable amounts of proteins. Presentation of this putative carbohydrate antigen (PjCHOAg) to CD8+ T cell clones is dependent on live antigen presenting cells (APCs) pulsed for >1 h at 37°C, suggesting that the antigen has to be internalized and possibly processed. Indeed, fixed APCs or APCs pulsed at 15°C were both unable to induce T cell response. Remarkably, PjCHOAg presentation is independent of the expression of classical major histocompatibility complex (MHC) molecules or CD1. CD8+ T cells stimulated by PjCHOAg-pulsed APCs undergo a sustained [Ca2+]i increase and downregulate their T cell antigen receptors (TCRs) in an antigen dose– and time-dependent fashion, similar to T cells stimulated by conventional ligands. Analysis of TCR Vβ transcripts shows that six independent PjCHOAg-specific T cell clones carry the Vβ8 segment with a conserved motif in the CDR3 region, indicating a structural requirement for recognition of this antigen. Finally, after activation, the CD8+ clones from the atopic patient express CD40L and produce high levels of interleukins 4 and 5, suggesting that the clones may have undergone a Th2-like polarization in vivo. These results reveal a new class of antigens which triggers T cells in an MHC-independent way, and these antigens appear to be carbohydrates. We suggest that this type of antigen may play a role in the immune response in vivo.


Retrovirology ◽  
2013 ◽  
Vol 10 (1) ◽  
pp. 116 ◽  
Author(s):  
Brian T Cain ◽  
Ngoc H Pham ◽  
Melisa L Budde ◽  
Justin M Greene ◽  
Jason T Weinfurter ◽  
...  

1996 ◽  
Vol 183 (4) ◽  
pp. 1603-1612 ◽  
Author(s):  
F M Marelli-Berg ◽  
R E Hargreaves ◽  
P Carmichael ◽  
A Dorling ◽  
G Lombardi ◽  
...  

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.


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