scholarly journals Characterization of apoptosis-resistant antigen-specific T cells in vivo.

1996 ◽  
Vol 183 (5) ◽  
pp. 2065-2073 ◽  
Author(s):  
L Zhang ◽  
R G Miller ◽  
J Zhang
Keyword(s):  
T Cells ◽  
Small Population ◽  
Peripheral Tolerance ◽  
Clonal Deletion ◽  
Fas L ◽  
Induced Apoptosis ◽  
High Level

Clonal deletion via activation-induced apoptosis (AIA) of antigen-specific T cells (ASTC) plays a very important role in the induction of peripheral tolerance. However, none of the studies performed so far has shown a complete deletion of ASTC, a small population always persisting in the periphery. The mechanism by which this small population of ASTC escapes AIA has not been determined. Since the existence of these ASTC may influence the outcome of autoimmune diseases and long-term graft survival, we have characterized the properties of these residual ASTC in vivo with the objective of determining mechanisms that may contribute to their persistence. It was found that the resistance of the residual ASTC to AIA is not due to lack of activation or Fas/Fas-L expression. Compared to those susceptible to AIA, the residual ASTC express a high level of Th2-type cytokines that may help them to escape from AIA. Furthermore, they are able to suppress proliferation of other ASTC, suggesting they may, in fact, prolong tolerance in vivo.

scholarly journals 255 Investigating VISTA’s role intrinsic to T cells in the tumor microenvironment

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A276-A276
Author(s):  
Cassandra Gilmour ◽  
Li Wang ◽  
Juan Dong ◽  
Sarah Stone ◽  
Keman Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Microenvironment ◽  
Tumor Immunity ◽  
Patient Survival ◽  
Cytotoxic T Cells ◽  
Peripheral Tolerance ◽  
Checkpoint Blockade

BackgroundCancer immunotherapies, specifically checkpoint blockade therapies, have demonstrated clinical importance for long term patient survival. One of the major limitations to checkpoint blockade therapies, is the low response rate: ~30% with anti-CTLA4 and anti-PD1 treatment. This may be due to heterogeneity of the patients‘ immune system and the tumor microenvironment including T cell inhibitions. There is a clear need to study this phenomenon and develop additional therapies for long term survival to include a broad range of patients. V-domain Immunoglobulin Suppressor of T-cell Activation (VISTA) is a suppressive protein expressed on many cell types in the tumor microenvironment including cytotoxic T cells. VISTA’s role on T cells has been described as maintaining quiescence and peripheral tolerance in a graft vs host disease model, but is not fully understood in context of the tumor microenvironment.MethodsWe use a series of invivo experiments, including T cell specific VISTA knock outs, to understand the role of VISTA on T cells in the tumor microenvironment.ResultsHere we show a series of in vivo experiments that suggest VISTA has a potent intrinsic role on T cells and therefore anti-tumor immunity. Using a T cell specific VISTA knock out, our results suggest that the absence of VISTA on T cells in combination with anti-CTLA4 and vaccine is a very powerful tumor suppressor compared to vaccine and anti-CTLA4 treatment alone. These results also indicate that the absence of VISTA alters the phenotype of cytotoxic T cells in several ways including the production of inflammatory cytokines.ConclusionsOur preliminary data provides foundation to study VISTA’s role intrinsic to T cells in the tumor microenvironment and how disrupting VISTA’s influence intrinsic to T cells may be advantageous for anti-tumor immunity and long term patient survival.Ethics ApprovalAll in vivo studies were reviewed and approved by Institutional Animal Care and Use Committee (Approval number 2019–2142).

Toxicological evaluation of Prussian blue nanoparticles after short exposure of mice

2016 ◽  
Vol 35 (10) ◽  
pp. 1123-1132 ◽  
Author(s):  
Y Chen ◽  
L Wu ◽  
Q Wang ◽  
M Wu ◽  
B Xu ◽  
...  
Keyword(s):  
T Cells ◽  
Prussian Blue ◽  
Short Exposure ◽  
Toxicological Evaluation ◽  
Prussian Blue Nanoparticles ◽  
High Level ◽  
Histological Results ◽  
Short Time

Prussian blue nanoparticle (PBNP), a new type of theranostic nanomaterial, had been used for cancer magnetic resonance imaging and photothermal therapy. However, their long-term toxicity after short exposure in vivo was still unclear. In this study, we investigated the dynamic changes of the biochemical and immunity indicators of mice after PBNPs injection through tail vein. Histological results showed that the PBNPs were mainly accumulated in liver and spleen. In the spleen, we found the frequency of T cells was starting to decrease after 1 day of PBNPs injection, but then slowly recovered to normal level after 60 days of injection. Meanwhile, the frequency of T cells in the blood was firstly decreased after the PBNPs injection, and then the T cell frequency kept increasing and recovered back to normal levels after 7 days of injection. The serum indexes of liver functions (alanine transaminase, aspartate transaminase, total bilirubin, and alkaline phosphatase) increased rapidly to a relatively high level only after 1 h of injection, which meant certain acute liver damage, but these indexes were gradually decreased to normal levels after 60 days of injection. These results indicate that PBNPs have acute toxicity in vivo, however, their long-term toxicity after short-time exposure is low, which might provide guidance for further applications of PBNPs in future.

scholarly journals Peripheral T cells undergoing superantigen-induced apoptosis in vivo express B220 and upregulate Fas and Fas ligand.

1996 ◽  
Vol 183 (2) ◽  
pp. 431-437 ◽  
Author(s):  
T Renno ◽  
M Hahne ◽  
J Tschopp ◽  
H R MacDonald
Keyword(s):  
T Cells ◽  
Fas Ligand ◽  
Apoptotic Cell ◽  
Initial Increase ◽  
Apoptotic Cells ◽  
Peripheral T Cells ◽  
Fas L ◽  
Induced Apoptosis

Staphylococcal enterotoxin B (SEB) is a bacterial superantigen (SAg) that predominantly interacts with V(beta)8+ T cells. In vivo treatment of mice with SEB leads to an initial increase in the percentage of V(beta)8+ T cells, followed by a decrease in the numbers of these cells, eventually reaching lower levels than those found before treatment with the SAg. This decrease is due to apoptosis of the SEB-responding cells. In the present study, we use the distinct light scattering characteristics of apoptotic cells to characterize T cells that are being deleted in response to SEB in vivo. We show that dying, SEB-reactive T cells express high levels of Fas and Fas ligand (Fas-L), which are implicated in apoptotic cell death. In addition, the B cell marker B220 is upregulated on apoptotic cells. Moreover, we show that the generation of cells with an apoptotic phenotype is severely impaired in response to SEB in functional Fas-L-deficient mutant gld mice, confirming the role of the Fas pathway in SAg mediated peripheral deletion in vivo.

102 Cord-blood derived NK cells, and CAR-T cells, an attractive improved immunotherapy treatment to be considered for hematological malignancies

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A113-A113
Author(s):  
Mireia Bachiller García ◽  
Lorena Pérez-Amill ◽  
Anthony Battram ◽  
Alvaro Urbano-Ispizua ◽  
Beatriz Martín-Antonio
Keyword(s):  
T Cells ◽  
Tumor Cell ◽  
Cord Blood ◽  
Immune Cells ◽  
In Vivo Models ◽  
Cell Clusters ◽  
Cytotoxicity Assays ◽  
Anti Tumor Activity

BackgroundMultiple myeloma (MM) remains an incurable hematological malignancy where a proportion of patients relapse or become refractory to current treatments. Administration of autologous T cells modified with a chimeric antigen receptor (CAR) against B cell maturation antigen (BCMA) has achieved high percentages of complete responses. Unfortunately, the lack of persistence of CART-BCMA cells in the patient leads to relapses. On the other side, cord-blood derived natural killer cells (CB-NK) is an off-the-shelf cellular immunotherapy option to treat cancer patients with high potential due to their anti-tumor activity. However, clinical results in patients up to date have been sub-optimal. Whereas CB-NK are innate immune cells and their anti-tumor activity is developed in a few hours, CART cells are adaptive immune cells and their activity develops at later time points. Moreover, we previously described that CB-NK secrete inflammatory proteins that promote the early formation of tumor-immune cell clusters bringing cells into close contact and thus, facilitating the anti-tumor activity of T cells. Therefore, we hypothesized that the addition of a small number of CB-NK to CART cells would improve the anti-tumor activity and increase the persistence of CART cells.MethodsT cells transduced with a humanized CAR against BCMA and CB-NK were employed at 1:0.5 (CART:CB-NK) ratio. Cytotoxicity assays, activation markers and immune-tumor cell cluster formation were evaluated by flow cytometry and fluorescence microscopy. In vivo models were performed in NSG mice.ResultsThe addition of CB-NK to CART cells demonstrated higher anti-MM efficacy at low E:T ratios during the first 24h and in long-term cytotoxicity assays, where the addition of CB-NK to CART cells achieved complete removal of tumor cells. Analysis of activation marker CD69 and CD107a degranulation from 4h to 24h of co-culturing proved differences only at 4h, where CD69 and CD107a in CART cells were increased when CB-NK were present. Moreover, CB-NK accelerated an increased formation of CART-tumor cell clusters facilitating the removal of MM cells. Of note, CB-NK addition did not increase total TNFα and IFNγ production. Finally, an in vivo model of advanced MM with consecutive challenge to MM cells evidenced that the addition of CB-NK achieved the highest efficacy of the treatment.ConclusionsOur results suggest that the addition of ‘off-the-shelf’ CB-NK to CART cells leads to a faster and earlier immune response of CART cells with higher long-term maintenance of the anti-tumor response, suggesting this combinatorial therapy as an attractive immunotherapy option for MM patients.

scholarly journals CD28 Costimulation Is Required for In Vivo Induction of Peripheral Tolerance in CD8 T Cells

2002 ◽  
Vol 197 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Melanie S. Vacchio ◽  
Richard J. Hodes
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Tolerance Induction ◽  
Peripheral Tolerance ◽  
Cd8 Cells ◽  
Costimulatory Signal ◽  
Cd28 Costimulation

Whereas ligation of CD28 is known to provide a critical costimulatory signal for activation of CD4 T cells, the requirement for CD28 as a costimulatory signal during activation of CD8 cells is less well defined. Even less is known about the involvement of CD28 signals during peripheral tolerance induction in CD8 T cells. In this study, comparison of T cell responses from CD28-deficient and CD28 wild-type H-Y–specific T cell receptor transgenic mice reveals that CD8 cells can proliferate, secrete cytokines, and generate cytotoxic T lymphocytes efficiently in the absence of CD28 costimulation in vitro. Surprisingly, using pregnancy as a model to study the H-Y–specific response of maternal T cells in the presence or absence of CD28 costimulation in vivo, it was found that peripheral tolerance does not occur in CD28KO pregnants in contrast to the partial clonal deletion and hyporesponsiveness of remaining T cells observed in CD28WT pregnants. These data demonstrate for the first time that CD28 is critical for tolerance induction of CD8 T cells, contrasting markedly with CD28 independence of in vitro activation, and suggest that the role of CD28/B7 interactions in peripheral tolerance of CD8 T cells may differ significantly from that of CD4 T cells.

scholarly journals TCR ligand density and affinity determine peripheral induction of Foxp3 in vivo

2010 ◽  
Vol 207 (8) ◽  
pp. 1701-1711 ◽  
Author(s):  
Rachel A. Gottschalk ◽  
Emily Corse ◽  
James P. Allison
Keyword(s):  
T Cells ◽  
Time Course ◽  
Low Dose ◽  
Cell Receptor ◽  
Peripheral Tolerance ◽  
Ligand Density ◽  
Forkhead Box ◽  
Histocompatibility Complex ◽  
Maximal Induction

T cell receptor (TCR) ligation is required for the extrathymic differentiation of forkhead box p3+ (Foxp3+) regulatory T cells. Several lines of evidence indicate that weak TCR stimulation favors induction of Foxp3 in the periphery; however, it remains to be determined how TCR ligand potency influences this process. We characterized the density and affinity of TCR ligand favorable for Foxp3 induction and found that a low dose of a strong agonist resulted in maximal induction of Foxp3 in vivo. Initial Foxp3 induction by weak agonist peptide could be enhanced by disruption of TCR–peptide major histocompatibility complex (pMHC) interactions or alteration of peptide dose. However, time course experiments revealed that Foxp3-positive cells induced by weak agonist stimulation are deleted, along with their Foxp3-negative counterparts, whereas Foxp3-positive cells induced by low doses of the strong agonist persist. Our results suggest that, together, pMHC ligand potency, density, and duration of TCR interactions define a cumulative quantity of TCR stimulation that determines initial peripheral Foxp3 induction. However, in the persistence of induced Foxp3+ T cells, TCR ligand potency and density are noninterchangeable factors that influence the route to peripheral tolerance.

scholarly journals Induction of Fas (Apo-1, CD95)-Mediated Apoptosis of Activated Lymphocytes by Polyclonal Antithymocyte Globulins

Blood ◽  
1998 ◽  
Vol 91 (7) ◽  
pp. 2360-2368 ◽  
Author(s):  
Laurent Genestier ◽  
Sylvie Fournel ◽  
Monique Flacher ◽  
Olga Assossou ◽  
Jean-Pierre Revillard ◽  
...  
Keyword(s):  
T Cells ◽  
Peripheral Blood ◽  
Fas Ligand ◽  
Mononuclear Cells ◽  
Resting Cells ◽  
Activated T Cells ◽  
Peripheral Blood Mononuclear ◽  
Gene And Protein Expression ◽  
Fas L ◽  
Induced Apoptosis

Polyclonal horse antilymphocyte and rabbit antithymocyte globulins (ATGs) are currently used in severe aplastic anemia and for the treatment of organ allograft acute rejection and graft-versus-host disease. ATG treatment induces a major depletion of peripheral blood lymphocytes, which contributes to its overall immunosuppressive effects. Several mechanisms that may account for lymphocyte lysis were investigated in vitro. At high concentrations (.1 to 1 mg/mL) ATGs activate the human classic complement pathway and induce lysis of both resting and phytohemagglutinin (PHA)-activated peripheral blood mononuclear cells. At low, submitogenic, concentration ATGs induce antibody-dependent cell cytotoxicity of PHA-activated cells, but not resting cells. They also trigger surface Fas (Apo-1, CD95) expression in naive T cells and Fas-ligand gene and protein expression in both naive and primed T cells, resulting in Fas/Fas-L interaction-mediated cell death. ATG-induced apoptosis and Fas-L expression were not observed with an ATG preparation lacking CD2 and CD3 antibodies. Susceptibility to ATG-induced apoptosis was restricted to activated cells, dependent on IL-2, and prevented by Cyclosporin A, FK506, and rapamycin. The data suggest that low doses of ATGs could be clinically evaluated in treatments aiming at the selective deletion of in vivo activated T cells in order to avoid massive lymphocyte depletion and subsequent immunodeficiency.

scholarly journals Ex Vivo Isolation and Characterization of Cd4+Cd25+ T Cells with Regulatory Properties from Human Blood

2001 ◽  
Vol 193 (11) ◽  
pp. 1303-1310 ◽  
Author(s):  
Detlef Dieckmann ◽  
Heidi Plottner ◽  
Susanne Berchtold ◽  
Thomas Berger ◽  
Gerold Schuler
Keyword(s):  
T Cells ◽  
Cytotoxic T Lymphocyte ◽  
Ex Vivo ◽  
Cell Receptor ◽  
Regulatory Cells ◽  
Suppressor T Cells ◽  
Isolation And Characterization ◽  
Regulatory Properties

It has been known for years that rodents harbor a unique population of CD4+CD25+ “professional” regulatory/suppressor T cells that is crucial for the prevention of spontaneous autoimmune diseases. Here we demonstrate that CD4+CD25+CD45RO+ T cells (mean 6% of CD4+ T cells) are present in the blood of adult healthy volunteers. In contrast to previous reports, these CD4+CD25+ T cells do not constitute conventional memory cells but rather regulatory cells exhibiting properties identical to their rodent counterparts. Cytotoxic T lymphocyte–associated antigen (CTLA)-4 (CD152), for example, which is essential for the in vivo suppressive activity of CD4+CD25+ T cells, was constitutively expressed, and remained strongly upregulated after stimulation. The cells were nonproliferative to stimulation via their T cell receptor for antigen, but the anergic state was partially reversed by interleukin (IL)-2 and IL-15. Upon stimulation with allogeneic (but not syngeneic) mature dendritic cells or platebound anti-CD3 plus anti-CD28 the CD4+CD25+ T cells released IL-10, and in coculture experiments suppressed the activation and proliferation of CD4+ and CD8+ T cells. Suppression proved IL-10 independent, yet contact dependent as in the mouse. The identification of regulatory CD4+CD25+ T cells has important implications for the study of tolerance in man, notably in the context of autoimmunity, transplantation, and cancer.

scholarly journals Platelet Gene Therapy Promotes Targeted Peripheral Tolerance by Clonal Deletion and Induction of Antigen-Specific Regulatory T Cells

2018 ◽  
Vol 9 ◽  
Author(s):  
Xiaofeng Luo ◽  
Juan Chen ◽  
Jocelyn A. Schroeder ◽  
Kenneth P. Allen ◽  
Christina K. Baumgartner ◽  
...  
Keyword(s):  
Gene Therapy ◽  
T Cells ◽  
Regulatory T Cells ◽  
Peripheral Tolerance ◽  
Clonal Deletion

Analysis of in Vitro and in Vivo Characteristics of Human Embryonic Stem Cell-Derived Neural Precursors

2010 ◽  
Vol 19 (4) ◽  
pp. 471-486 ◽  
Author(s):  
Nataliya Kozubenko ◽  
Karolina Turnovcova ◽  
Miroslava Kapcalova ◽  
Olena Butenko ◽  
Miroslava Anderova ◽  
...  
Keyword(s):  
Embryonic Stem ◽  
Cellular Heterogeneity ◽  
Neural Cells ◽  
Lineage Specification ◽  
Neural Precursors ◽  
Selection Strategies

During the last decade, much progress has been made in developing protocols for the differentiation of human embryonic stem cells (hESCs) into a neural phenotype. The appropriate agent for cell therapy is neural precursors (NPs). Here, we demonstrate the derivation of highly enriched and expandable populations of proliferating NPs from the CCTL14 line of hESCs. These NPs could differentiate in vitro into functionally active neurons, as confirmed by immunohistochemical staining and electrophysiological analysis. Neural cells differentiated in vitro from hESCs exhibit broad cellular heterogeneity with respect to developmental stage and lineage specification. To analyze the population of the derived NPs, we used fluorescence-activated cell sorting (FACS) and characterized the expression of several pluripotent and neural markers, such as Nanog, SSEA-4, SSEA-1, TRA-1-60, CD24, CD133, CD56 (NCAM), β-III-tubulin, NF70, nestin, CD271 (NGFR), CD29, CD73, and CD105 during long-term propagation. The analyzed cells were used for transplantation into the injured rodent brain; the tumorigenicity of the transplanted cells was apparently eliminated following long-term culture. These results complete the characterization of the CCTL14 line of hESCs and provide a framework for developing cell selection strategies for neural cell-based therapies.

Sign in / Sign up

Export Citation Format

Share Document