The In Vivo Impact of Human Regulatory T Cells on the Graft Versus Tumor Effect.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 349-349 ◽  
Author(s):  
Tuna Mutis ◽  
Henk Rozemuller ◽  
Maarten E. Emmelot ◽  
Tineke Aarts-Riemens ◽  
Vivienne Verweij ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Tumor Cells ◽  
Cell Reactivity ◽  
Human Pbmc ◽  
Ifn Γ ◽  
T Cell Reactivity ◽  
The Impact

Abstract The curative Graft-vs-Tumor effect (GvT) of allogeneic Stem cell transplantation (SCT) is frequently complicated with life threatening Graft-vs-Host Disease (GvHD). In mice, prevention of GvHD, without abrogation of GvT is possible by co-transplantation of naturally occurring regulatory T cells (Tregs) with SC grafts. Consistent with these murine studies, we recently demonstrated that also human Tregs possess potent GvHD-downregulatory capacities in a xenogeneic(x) model, where x-GvHD is induced by infusion of autologous human T cells in RAG2−/−γc−/− mice (Mutis et al. Clin. Cancer Res.2006, 12: 5520–5525). Towards clinical application of Tregs, we now explored the impact of human Treg-administration on GvT in a bioluminescence imaging (BLI) based human-GvT model in the RAG2−/−γc−/− mice. In this model, mice inoculated with luciferase (LUC)-transduced human myeloma (MM) cell lines developed BLI-detectable, progressive, MM-like multifocal tumors exclusively in the bone marrow (BM). Full blown tumors were effectively eliminated by infusion of allogeneic human PBMC. This treatment also caused lethal x-GvHD as expected. In this setting, co-infusion of human PBMC with autologous, in vitro cultured Tregs at a 1:1 Treg: T effector cell ratio had no adverse effects on the development of GvT while significantly reducing the lethality of x-GvHD. In vitro analyses of sacrificed mice at day 21 revealed that administered Tregs homed to BM and spleen, significantly downregulated the total numbers of IFN-γ-producing CD4+ and CD8+ T cells responding to CD3 mediated signals, but had no downregulatory effect on the frequencies of IFN-γ-producing T cells responding to tumor cells. There was also no downregulation of cytotoxic activity against tumor cells in Treg-treated mice. Conclusively, these results showed that Tregs, at doses which are inhibitory for x-GvHD-inducing T cells, could maintain the GvT effect by allowing T cell reactivity against tumor cells. Human Tregs thus still hold promise as attractive cellular tools for separating GvT from GvHD.

scholarly journals IL-2 administration increases CD4+CD25hi Foxp3+ regulatory T cells in cancer patients

Blood ◽  
2006 ◽  
Vol 107 (6) ◽  
pp. 2409-2414 ◽  
Author(s):  
Mojgan Ahmadzadeh ◽  
Steven A. Rosenberg
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Interleukin 2 ◽  
Selective Inhibition ◽  
High Dose ◽  
Protein Levels ◽  
And Function ◽  
The Impact

Abstract Interleukin-2 (IL-2) is historically known as a T-cell growth factor. Accumulating evidence from knockout mice suggests that IL-2 is crucial for the homeostasis and function of CD4+CD25+ regulatory T cells in vivo. However, the impact of administered IL-2 in an immune intact host has not been studied in rodents or humans. Here, we studied the impact of IL-2 administration on the frequency and function of human CD4+CD25hi T cells in immune intact patients with melanoma or renal cancer. We found that the frequency of CD4+CD25hi T cells was significantly increased after IL-2 treatment, and these cells expressed phenotypic markers associated with regulatory T cells. In addition, both transcript and protein levels of Foxp3, a transcription factor exclusively expressed on regulatory T cells, were consistently increased in CD4 T cells following IL-2 treatment. Functional analysis of the increased number of CD4+CD25hi T cells revealed that this population exhibited potent suppressive activity in vitro. Collectively, our results demonstrate that administration of high-dose IL-2 increased the frequency of circulating CD4+CD25hi Foxp3+ regulatory T cells. Our findings suggest that selective inhibition of IL-2-mediated enhancement of regulatory T cells may improve the therapeutic effectiveness of IL-2 administration. (Blood. 2006;107:2409-2414)

Gvhd Severity Is Regulated by the Adoptive Transfer Low Numbers of NKT Cells by a Mechanism Distinct From CD4+CD25+ Regulatory T Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 229-229
Author(s):  
Dennis Leveson-Gower ◽  
Janelle Olson ◽  
Emanuela I Sega ◽  
Jeanette Baker ◽  
Robert Zeiser ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Adoptive Transfer ◽  
Conflicts Of Interest ◽  
Serum Levels ◽  
Nkt Cells ◽  
Donor Type ◽  
Ifn Γ ◽  
The Impact

Abstract Abstract 229 NKT cells, a subset of which are CD1d reactive, play an important immunoregulatory role in suppressing dysfunctional immune reactions, including graft-versus-host disease (GVHD). To explore the biological activity and mechanism of donor-type NKT in suppression of GVHD, we utilized highly purified (>95%) populations of donor (C57Bl6; H-2b) NKT (DX5+TCR+CD4+) cells adoptively transferred into lethally irradiated recipient (Balb/c; H-2d) animals with T cell depleted bone marrow (TCD-BM). Highly purified (>95%) NKT cells (5.5×105) from luciferase positive (luc+) C57BL/6 mice were infused into lethally irradiated Balb/c recipients with TCD-BM(5×106) from wild-type (WT) C57BL/6 mice, and the animals were monitored by bioluminescence imaging (BLI). By day 4 after transfer, an NKT derived signal was observed in spleen and lymph node (LN) sites, and between days 7 and 10, NKT had also migrated to the skin. Total photons emitted peaked near day 25 after transplantation, followed by a steady decline. To assess the impact of donor-type NKT cells on GVHD induction by conventional CD4+ and CD8+ T cells (Tcon), we co-transferred various doses of highly purified WT NKT at day 0 with TCD-BM, followed by 5×105 luc+Tcon/animal on day 2. As few as 2.5×104 NKT cells significantly improved survival of mice receiving 5×105 Tcon. Animal survival with Tcon only was 20% and for Tcon with NKT cells was 74%(p=0.0023). In contrast to what is observed with CD4+CD25+FoxP3+ regulatory T cells (Treg), the NKT cells did not suppress Tcon proliferation assayed by both in vivo BLI and in a mixed-leukocyte reaction. Analysis of serum cytokines with or without 2.5×104 NKT, following HCT with TCD-BM and Tcon, indicated the addition of NKT cells resulted in elevated levels of INF-γ, IL-5, and IL-6 in serum; significant differences were not observed in serum levels of IL-2, IL-4, IL-10, IL-17, or TNF-α. Intracellular levels of cytokines in Tcon were analyzed from the same groups. At 8 days after HCT, mice receiving NKT had fewer TNFα-positive cells in LNs (CD4: 45% to 27%; CD8 36% to 24%); by day 11, however, TNFαa levels between groups were equivalent. IFN-γ levels, which were high in both NKT treated and untreated groups at day 8 (85%-95%), decreased significantly in NKT treated mice by day 11 (CD4: 40%; CD8: 43%), but were abundant in Tcon only mice (CD4: 78%; CD8: 80%) (p=.0001). No significant changes were found in the intracellular levels of IL-2, IL-4, IL-5, IL-10, or IL-17 of Tcon in the presence or absence of NKT cells. NKT from both IL-4 -/- and IFN-γ -/- mice were less effective at suppressing GVHD than WT NKT, implicating these cytokines in the suppressive mechanism. Finally, we found that NKT do not have a major impact on the graft-versus-tumor effect of Tcon against a luc+ BCL-1 tumor. These studies indicate that NKT persist in vivo upon adoptive transfer and suppress GVHD, even at extremely low cell numbers, which is important given the relative paucity of this cell population. The mechanisms of GVHD suppression appear to be distinct to those of Treg and involve the production of IL-4 and IFN-γ by NKT resulting in a decrease in Tcon, which produce pro-inflamatory cytokines. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Regulation of cytotoxic T-cell reactivity to syngeneic tumors by the thymus.

1978 ◽  
Vol 148 (2) ◽  
pp. 619-623 ◽  
Author(s):  
C L Reinisch ◽  
S L Andrew
Keyword(s):  
T Cells ◽  
Tumor Cells ◽  
Cytotoxic T Cell ◽  
Target Cells ◽  
Cell Reactivity ◽  
Syngeneic Tumor ◽  
T Cell Reactivity ◽  
Syngeneic Tumors ◽  
Thymectomized Mice

Adult thymectomy has been shown to result in the enhanced capacity of splenic T cells to respond to and lyse syngeneic tumor cells in vitro. In addition, T cells from thymectomized mice which kill syngeneic tumor cells do not lyse either normal lymphoid or mitogen-stimulated syngeneic lymphoblast target cells. These findings indicate that the thymus exports a subpopulation of T cells sensitive to adult thymectomy which regulates the generation of cytolytic T cells directed against syngeneic tumor cells.

Impact of mTOR Inhibition on FoxP3+ Regulatory T Cells as Compared to Conventional T Cells after Allogeneic Bone Marrow Transplantation.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 448-448 ◽  
Author(s):  
Robert Zeiser ◽  
Dennis B. Leveson-Gower ◽  
Elizabeth A. Zambricki ◽  
Jing-Zhou Hou ◽  
Robert Negrin
Keyword(s):  
Clinical Trials ◽  
T Cells ◽  
Regulatory T Cells ◽  
Allogeneic Bone Marrow Transplantation ◽  
Inhibitory Effect ◽  
Allogeneic Bone ◽  
Mtor Inhibition ◽  
The Impact

Abstract FoxP3+CD4+CD25+ regulatory T-cells (Treg) have been shown to effectively reduce the severity of experimental acute graft-versus-host disease (aGvHD) while sparing graft-versus-leukemia activity. These findings, in concert with the observation that human and murine Treg share functional characteristics, have fueled interest in clinical trials to control aGvHD. Recent data indicates that the immunosuppressant rapamycin (RAPA) in contrast to cyclosporine A does not interfere with in vivo function of Treg and could enhance Treg expansion in vitro by a yet unknown mechanism. To investigate the impact of mTOR inhibition on proliferating Treg and Tconv, both cell types were exposed to CD3/CD28 Mabs in the presence of different RAPA concentrations in vitro. Phosphorylation of mTOR downstream products p70S6K1 and 4E-BP1 were assessed by western blot and flow cytometry. Inhibition of the phosphorylation of p70S6K1 and 4E-BP1 was observed in both populations in the presence of RAPA. Interestingly, Treg were more resistant to mTOR inhibition as compared to Tconv and displayed significantly higher phosphorylated products in the presence of RAPA at 10 nM (MFI Treg vs Tconv, p<0.001) and at 100nM (MFI Treg vs Tconv, p<0.001). To investigate whether Treg and RAPA protect from aGvHD in a synergistic manner, BALB/c recipients were transplanted with H-2 disparate BM and 1.6x10e6 T-cells (FVB/N) after lethal irradiation (8 Gy). aGvHD lethality was only slightly reduced when suboptimal Tconv:Treg ratios were employed (4:1, 8:1), or when recipients were treated with a non-protective RAPA dose (0.5 mg/kg bodyweight). Combining a suboptimal Tconv:Treg ratio with a non-protective RAPA dose reduced expansion of luciferase expressing (luc+) Tconv and pro-inflamatory cytokines and improved survival indicative for an additive in vivo effect of RAPA and Treg. To evaluate the impact of RAPA on in vivo T cell expansion, either luc+ Tconv or luc+ Treg were adoptively transferred. In vivo bioluminescence imaging demonstrated that RAPA had a more potent inhibitory effect on proliferation of Tconv as compared to Treg (p<0.05 vs. NS). We did not observe RAPA to increase FoxP3+ Treg numbers in vivo, or to enhance GITR or CTLA-4 expression. Thus, increased Treg numbers observed in RAPA containing expansion cultures are likely due to a lower susceptibility of this cell population to mTOR inhibition. This could explain the observed synergistic effect of RAPA and Treg in aGvHD protection which has relevance for clinical trials utilizing Treg to prevent aGvHD.

scholarly journals 153 Nanoscale, antigen-dependent, IL-12 delivery by CAR T cells plus PD-L1 blockade for cancer treatment

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A162-A163
Author(s):  
Zhifen Yang ◽  
Francesco Marincola
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Car T Cells ◽  
Car T ◽  
Ifn Γ ◽  
High Doses ◽  
Fadu Cells

BackgroundInterleukin(IL)-12 activates T cells pivoting the switch that turns lingering inflammation into acute inflammation and cancer rejection. However, its clinical utilization is limited by severe systemic toxicity. IL-12 is a potent inducer of PD-1 expression in T cells. Here, we present a conditional, antigen-dependent, non-editing CRISPR-activation (CRISPRa) circuit (RB-312) that delivers nanoscale doses of IL-12 for autocrine activation of CAR-T cells. RB-312 was also tested in combination with PD-L1 blocking antibody (atezolizumab).MethodsRB-312 is a CAR T cell engineered to express the IL-12 heterodimer via conditional transcription of its two endogenous subunits p35 and p40. The circuit includes two lentiviral constructs with one encoding HER2-specific chimeric antigen receptor and two sgRNAs targeting IL-12A or IL-12B and the other encoding linker for activation of T cells, complexed to dead Cas9 (dCas9)-VP64-p65-Rta transcriptional activator (VPR) (LdCV). Activation of CAR allows the release of dCas9 for nuclear localization and hence conditionally and reversibly induces the secretion of IL-12 p70 heterodimer.ResultsRB-312 induced low concentrations of IL-12 upon exposure to HER2+ FaDu cancer cells engineered to overexpress PD-L1 and this resulted in significantly enhanced production of IFN-γ, cytotoxicity and CAR-T proliferation (figure 1A). These effects were comparable to co-culturing conventional HER2 CAR with FaDu cells modified to express high doses of IL-12 (figure 1B). In vivo administration of RB-312 significantly enhanced survival of mice carrying FaDu xenografts compared to mice treated with the respective conventional HER2 CAR or cRB-312 (control lacking the IL-12 sgRNAs, figure 2A). RB-312 induced a strong upregulation of PD-1 in CAR-T cells in vivo (figure 2B). The critical role of the PD-1/PD-L1 interaction was demonstrated in vitro by comparing RB-312 proliferation when exposed to FaDu overexpressing PD-L1 or PD-L1 knock out cells (figure 3A). Indeed, combined treatment of RB-312 and atezolizumab resulted in significant reduction in tumor growth (figure 3B and C) and significantly enhanced survival (figure 3D).Abstract 153 Figure 1Conditional autocrine release of nanoscale-dose p70/IL-12 by RB-312 resulting in enhanced IFN-γ production in vitro after three days of exposure to HER2+ FaDu cells (figure 1A), and the level of IFN-γ production was comparable to co-culturing conventional HER2-specific CAR-T cells with a modified FaDu cell line engineered to constitutively express high doses of IL-12 (FaDu/IL-12, figure 1B)Abstract 153 Figure 2Intra-tumoral administration of RB-312 extended survival in mice carrying FaDu xenografts compared to NT (non-transduced T cells), HER2 CAR (conventional HER2 CAR-T cells) and cRB-312 CAR-T cells missing the sgRNAs for the two IL-12 subunits (figure 2A). Analysis of necropsy material demonstrated that PD-1 expression was dramatically increased in RB-312 compared with the respective control cRB-312 (figure 2B)Abstract 153 Figure 3RB-312 cellular function in vivo. PD-L1 expression by FaDu cell lines is a critical mechanism of repression of RB-312 function. In vitro CAR-T proliferation of RB-312 upon stimulation with FaDu tumor cells (orange solid lines) or FaDu/PD-L1 knockout tumor cells (orange dashed lines) over 6-day time course (figure 3A). In vivo efficacy of intra-tumoral RB-312 against FaDu tumor cells with (orange solid lines) or without (orange dashed lines) addition of PD-L1 blocking antibody atezolizumab (administered intravenously at 5 mg/kg twice per week), as shown by tumor growth followed till day 29 and scatter plot at day 29 (figure 3B), tumor growth spider plots (figure 3C) and Kaplan-Meier survival curve (figure 3D)ConclusionsWe concluded that addition of a Th1 polarizing component such as IL-12 exponentially increases the efficacy of reprogrammed CAR-T cells by combining enhancement of effector functions to cellular fitness. The autocrine effects of nanoscale IL-12 production limit the risk of off-tumor leakage and systemic toxicity. Here, we tested the combination of PD-1/PD-L1 blockade with IL-12-induced CAR-T cell activation demonstrated dramatic synergistic effects. We are currently evaluating the intrinsic combination of IL-12 delivery and PD-L1 resistance for the next generation of RB-312 product eliminating the need for systemic checkpoint blockade.

The impact of Zataria multiflora Boiss extract on in vitro and in vivo Th1/Th2 cytokine (IFN-γ/IL4) balance

2013 ◽  
Vol 150 (3) ◽  
pp. 1024-1031 ◽  
Author(s):  
Mohammad Hossein Boskabady ◽  
Sakine Shahmohammadi Mehrjardi ◽  
Abadorrahim Rezaee ◽  
Houshang Rafatpanah ◽  
Sediqeh Jalali
Keyword(s):  
Zataria Multiflora ◽  
Th2 Cytokine ◽  
Ifn Γ ◽  
The Impact

scholarly journals MiR-146a regulates regulatory T cells to suppress heart transplant rejection in mice

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jian Lu ◽  
Weiwei Wang ◽  
Peiyuan Li ◽  
Xiaodong Wang ◽  
Chao Gao ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Heart Transplant ◽  
Transplant Rejection ◽  
Mouse Heart ◽  
Allograft Survival ◽  
Treg Function ◽  
Ifn Γ ◽  
Heart Transplant Rejection

AbstractRegulatory T cells (Tregs), which characteristically express forkhead box protein 3 (Foxp3), are essential for the induction of immune tolerance. Here, we investigated microRNA-146a (miR-146a), a miRNA that is widely expressed in Tregs and closely related to their homeostasis and function, with the aim of enhancing the function of Tregs by regulating miR-146a and then suppressing transplant rejection. The effect of the absence of miR-146a on Treg function in the presence or absence of rapamycin was detected in both a mouse heart transplantation model and cell co-cultures in vitro. The absence of miR-146a exerted a mild tissue-protective effect by transiently prolonging allograft survival and reducing the infiltration of CD4+ and CD8+ T cells into the allografts. Meanwhile, the absence of miR-146a increased Treg expansion but impaired the ability of Tregs to restrict T helper cell type 1 (Th1) responses. A miR-146a deficiency combined with interferon (IFN)-γ blockade repaired the impaired Treg function, further prolonged allograft survival, and alleviated rejection. Importantly, miR-146a regulated Tregs mainly through the IFN-γ/signal transducer and activator of transcription (STAT) 1 pathway, which is implicated in Treg function to inhibit Th1 responses. Our data suggest miR-146a controls a specific aspect of Treg function, and modulation of miR-146a may enhance Treg efficacy in alleviating heart transplant rejection in mice.

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