scholarly journals Pretreatment of murine donor grafts with L-leucyl-L-leucine methyl ester: elimination of graft-versus-host disease without detrimental effects on engraftment

Blood ◽  
1990 ◽  
Vol 75 (3) ◽  
pp. 798-805 ◽  
Author(s):  
BR Blazar ◽  
DL Thiele ◽  
DA Vallera
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Methyl Ester ◽  
Graft Versus Host Disease ◽  
Host Cells ◽  
Host Disease ◽  
Murine Bone Marrow ◽  
Graft Versus Host

Abstract Incubation of murine bone marrow and splenocytes with the dipeptide methyl ester, L-leucyl-L-leucine methyl ester (Leu-Leu-OMe), which results in the selective depletion of cytotoxic T cells and their precursors, natural killer cells, and monocytes, completely protected 30 recipients of fully allogeneic donor grafts from lethal graft-versus- host disease (GVHD). These results were comparable with those obtained in 30 recipients of anti-Thy 1.2 plus complement (C')-treated donor marrow. However, in contrast to antibody- and C'-dependent T-cell depletion, which reduces the level of donor cell engraftment in our model system, we did not observe such effects using Leu-Leu-OMe marrow pretreatment. As compared with the 24 H-2 typed recipients of anti-Thy 1.2 + C'-treated donor grafts, the 29 H-2 typed recipients of Leu-Leu- OMe-treated donor grafts had significantly (P less than .001) higher percentages of donor cells (mean = 93% v 74%) and significantly (P less than .001) lower percentages of host cells (mean = 6% v 15%) posttransplantation. In vitro limiting dilution assay (LDA) was performed to assess the comparative efficacy of cytolytic T-lymphocyte (CTL) precursor depletion by Leu-Leu-OMe or anti-Thy 1.2 + C' pretreatment. We observed greater levels of CTL precursor depletion in Leu-Leu-OMe treated as compared with anti-Thy 1.2 + C'-treated bone marrow plus spleen cells (BMS) obtained from nontransplanted mice. This suggests that the in vivo results cannot simply be attributed to a less efficacious functional inactivation of cytolytic T-cell precursors by Leu-Leu-OMe treatment as compared with anti-Thy 1.2 + C' treatment. Immunoreconstitution was similar in recipients of Leu-Leu-OMe-treated grafts and anti-Thy 1.2 + C'-treated grafts 100 days posttransplant. In our opinion, Leu-Leu-OMe marrow pretreatment deserves further investigation as a methodology to achieve GVHD prevention without significantly reducing the propensity toward host cell repopulation.

scholarly journals Pretreatment of murine donor grafts with L-leucyl-L-leucine methyl ester: elimination of graft-versus-host disease without detrimental effects on engraftment

Blood ◽  
1990 ◽  
Vol 75 (3) ◽  
pp. 798-805
Author(s):  
BR Blazar ◽  
DL Thiele ◽  
DA Vallera
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Methyl Ester ◽  
Graft Versus Host Disease ◽  
Host Cells ◽  
Host Disease ◽  
Murine Bone Marrow ◽  
Graft Versus Host

Incubation of murine bone marrow and splenocytes with the dipeptide methyl ester, L-leucyl-L-leucine methyl ester (Leu-Leu-OMe), which results in the selective depletion of cytotoxic T cells and their precursors, natural killer cells, and monocytes, completely protected 30 recipients of fully allogeneic donor grafts from lethal graft-versus- host disease (GVHD). These results were comparable with those obtained in 30 recipients of anti-Thy 1.2 plus complement (C')-treated donor marrow. However, in contrast to antibody- and C'-dependent T-cell depletion, which reduces the level of donor cell engraftment in our model system, we did not observe such effects using Leu-Leu-OMe marrow pretreatment. As compared with the 24 H-2 typed recipients of anti-Thy 1.2 + C'-treated donor grafts, the 29 H-2 typed recipients of Leu-Leu- OMe-treated donor grafts had significantly (P less than .001) higher percentages of donor cells (mean = 93% v 74%) and significantly (P less than .001) lower percentages of host cells (mean = 6% v 15%) posttransplantation. In vitro limiting dilution assay (LDA) was performed to assess the comparative efficacy of cytolytic T-lymphocyte (CTL) precursor depletion by Leu-Leu-OMe or anti-Thy 1.2 + C' pretreatment. We observed greater levels of CTL precursor depletion in Leu-Leu-OMe treated as compared with anti-Thy 1.2 + C'-treated bone marrow plus spleen cells (BMS) obtained from nontransplanted mice. This suggests that the in vivo results cannot simply be attributed to a less efficacious functional inactivation of cytolytic T-cell precursors by Leu-Leu-OMe treatment as compared with anti-Thy 1.2 + C' treatment. Immunoreconstitution was similar in recipients of Leu-Leu-OMe-treated grafts and anti-Thy 1.2 + C'-treated grafts 100 days posttransplant. In our opinion, Leu-Leu-OMe marrow pretreatment deserves further investigation as a methodology to achieve GVHD prevention without significantly reducing the propensity toward host cell repopulation.

Host γd T cells Exacerbate Experimental Acute Graft-Versus-Host Disease through Activation of Host Antigen Presenting Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3045-3045
Author(s):  
Yoshinobu Maeda ◽  
Pavan Reddy ◽  
Chen Liu ◽  
D. Keith Bishop ◽  
James L.M. Ferrara
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Graft Versus Host Disease ◽  
Serum Levels ◽  
Host Disease ◽  
Graft Versus Host ◽  
Full Intensity

Abstract Large numbers of T cells bearing γd T cell receptors are present in graft-versus-host disease (GVHD) target tissues. We investigated the potential role of host γd T cells during acute GVHD in a well-characterized GVHD model following full intensity conditioning (11 Gy TBI). BM and spleen T cells from BALB/c (H2d) donors were transplanted into wild type (wt) B6, aß T cell deficient B6 (aß −/−) or γd T cell deficient B6 (γd −/−) hosts. γd −/− hosts demonstrated significantly better day 35 survival (85%) than wt (40%) or aß−/− hosts (18%) (P<0.05). Reconstitution of γd −/− B6 hosts with B6 type γd T cells 24 hr prior to BMT restored lethal GVHD (50 % day 35 survival). In vivo, γd −/− B6 hosts demonstrated at least a five fold reduction in donor T cell expansion and cytokine production. In vitro, T cells proliferated less when co-cultured with allogeneic γd −/− dendritic cells (DCs) than with wt DCs (40,127 ± 1634 vs. 72,503 ± 1296, P<0.05). BM-derived DCs cultured with γd T cells caused greater proliferation of allogeneic T cells than DCs cultured with aß T cells (15.1 ± 21 x 104 vs. 5.1 ± 1.2 x 104, P<0.05). We next tested the effect of γd T cells on host DCs in vivo using a model system in which only the DCs injected prior to BMT expressed the alloantigen that stimulated the GVHD reaction. MHC Class II −/− B6 mice that had been depleted of γd T cells were given 11 Gy TBI and injected one day prior to BMT with B6 DCs that had been co-cultured either with γd T cells or with medium. On day 0 both groups of recipient mice were injected with BM plus splenic T cells from allogeneic bm12 donors. On day +5, CD4+ donor T cells expanded four times more in recipients of DCs co-cultured with γd T cells than in recipients of control DCs and serum levels of TNF-a were significantly higher (36.7 + 6.8 vs. 21.3 + 3.7 pg/ml, P<0.05). Together these data demonstrate that γd T cells amplify the stimulatory function of host DCs and increase the severity of GVHD, suggesting that a new therapeutic target for the prevention of the major BMT toxicity.

Donor Dual TCR T Cells Preferentially Expand and Mediate Pathologic Alloreactivity in Acute Graft Versus Host Disease

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1972-1972
Author(s):  
Gerald P. Morris ◽  
Geoffrey L Uy ◽  
David L Donermeyer ◽  
Paul M Allen ◽  
John F. DiPersio
Keyword(s):  
T Cells ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
Peripheral Blood ◽  
Thymic Selection ◽  
Cell Repertoire ◽  
Host Disease ◽  
Graft Versus Host

Abstract Abstract 1972 The nature of the T cell repertoire mediating pathologic in vivo alloreactivity is an important question for understanding the development of acute graft-versus-host disease (aGvHD) following clinical allogeneic transplantation. We have previously demonstrated that the small proportion of T cells that naturally express 2 T cell receptors (TCR) as a consequence of incomplete TCRa allelic exclusion during thymic development contribute disproportionately to the alloreactive T cell repertoire, both in vitro and in vivo in a mouse model of graft versus host disease (GvHD) (J. Immunol., 182:6639, 2009). Here, we extend these findings to human biology, examining dual TCR T cells from healthy volunteer donors (n = 12) and patients who have undergone allogeneic hematopoietic stem cell transplantation (HSCT) (n = 19). Peripheral blood was collected at day 30 post-HSCT or at the time of presentation with symptomatic acute GvHD. Dual TCR T cells were measured in peripheral blood by pair-wise staining with 3 commercially-available and 2 novel TCRa mAbs. Dual TCR T cells were consistently and significantly expanded in patients with symptomatic aGvHD, representing 5.3±3.8 % of peripheral T cells, compared to 1.7±0.8 % of T cells in healthy controls (p < 0.005) (Figure 1). There was no correlation between dual TCR T cell frequency and GvHD severity. Furthermore, sequential analysis of peripheral blood in 2 patients demonstrated expansion of dual TCR T cells concurrent with the development of aGvHD (Figure 2). Dual TCR T cells from patients with symptomatic aGvHD demonstrated increased expression of CD69 as compared to T cells expressing a single TCR, indicative of preferential activation of dual TCR T cells during aGvHD. Similarly, dual TCR T cells isolated from patients with symptomatic aGvHD demonstrate increased production of IFN-g ex vivo, indicative of the ability to mediate pathogenic alloreactive responses. Dual TCR T cell clones isolated from healthy donors and patients post-HSCT by single cell FACS sorting demonstrate alloreactive responses against a range of allogeneic cell lines in vitro. We propose that the increased alloreactivity of dual TCR T cells results from the less stringent thymic selection for secondary TCR, and thus provides a link between thymic selection, the TCR repertoire, and alloreactivity. These findings may lead to simple ways of phenotypically identifying specific T cells predisposed to inducing aGvHD for subsequent examination of T cell repertoires and functional studies. Furthermore, these data suggest that dual TCR T cells represent a potential predictive biomarker for aGvHD and a potential target for selective T cell depletion in HSCT. Disclosures: No relevant conflicts of interest to declare.

Inhibition of Graft-Versus-Host Disease (GVHD) by Histone Deacetylase Inhibitor (HDAC) SAHA Leads to Downregulation of STAT1 Activation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1311-1311
Author(s):  
Corinna Leng ◽  
Cuiling Li ◽  
Judy Ziegler ◽  
Anna Lokshin ◽  
Suzanne Lentzsch ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Histone Deacetylase ◽  
Graft Versus Host Disease ◽  
Host Disease ◽  
Graft Versus Host ◽  
Tnf Α ◽  
Ifn Γ

Abstract Histone deacetylase (HDAC) inhibitors have been shown to reduce development of graft versus host disease [GVHD] following allogeneic bone marrow transplantation [BMT]. Administration of the HDAC inhibitor suberonylanilide hydroxamic acid [SAHA] resulted in a significantly reduced GVHD-dependent mortality following fully MHC-mismatched allogeneic BMT. Median Survival Time (MST) for vehicle and SAHA-treated mice were 7.5 days and 38 days respectively. However, SAHA treatment did not affect T cell activation nor T cell expansion in vitro and in vivo as determined by MLR assays, phenotypic analysis of donor T cells with regard to expression of the CD25 activation antigen and calculation of donor CD4+ and CD8+ T cell numbers on days +3 and +6 post-BMT. Thus, SAHA treatment was not able to inhibit the strong upregulation of CD25 antigen on CD8+ T cells observed during induction of GVHD on days +3 and +6 post-BMT. We therefore focused on the effects of SAHA treatment on efferent immune effects including cytokine secretion and intracellular signaling events in vitro and in vivo following GVHD induction. SAHA treatment broadly inhibited lipopolysaccharide [LPS] and allo-antigen-induced cytokine/chemokine secretion in vitro like MIP-1-α, IP-10, IFN-γ, TNF-α and IL-6 and led also to a significant decrease in IFN-γ and TNF-α levels in vivo following induction of GVHD. Concomitantly, SAHA treatment inhibited phosphorylation of STAT1 and STAT3 in response to LPS and allo-activation in vitro. Furthermore, analysis of liver tissue and spleens from SAHA-treated animals with GVHD showed a significant decrease in phosphorylated STAT1. In contrast SAHA treatment had only moderate effects on p38 or ERK1,2 Mitogen-activated Protein Kinase (MAPK) pathway underscoring the relevance of the inhibition of the STAT1 pathway. In conclusion, GVHD is associated with a strong induction of phosphorylation of STAT1 in the liver and spleen and SAHA-dependent reduction of GVHD is associated with systemic and local inhibition of pSTAT1 and modulation of the inflammatory cytokine milieu during the efferent immune response.

Inhibition Of The Immunoproteasome Subunit LMP7 Decreases Alloresponses In Both MHC-Mismatched and miHA-Disparate Murine Models Of Graft Versus Host Disease

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4472-4472
Author(s):  
Jennifer Matos ◽  
Zheng Yang ◽  
Eugenia Dziopa ◽  
Leah Dziopa ◽  
Christopher J. Kirk ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
Research Funding ◽  
Host Cells ◽  
Mhc I ◽  
Host Disease ◽  
Graft Versus Host ◽  
Drug Regimens

Background Proteasome inhibition has been studied and used as a therapeutic target in the treatment of autoimmune disorders and multiple myeloma. Immune system cells, especially antigen-presenting cells, express a higher basal level of immunoproteasomes, which are used to generate peptides that can be processed to fit in the groove of MHC class I molecules. ONX 0914 is a selective inhibitor of the immmunoproteasome that blocks LMP7-specific presentation of MHC-I restricted antigens, whereas PR-825 is a specific inhibitor of the b5 catalytic subunit generated by the constitutive proteasome. In previous work, we found that ONX 0914 administration early after transplantation significantly improved the survival of recipient mice in an MHC-matched minor histocompatibility antigen (miHA)-disparate (B10.BR -> CBA, lethally irradiated) murine model of graft-versus-host disease (GVHD). To further elucidate the mechanism of action, we compared alloreactive responses via IFN-g production in mixed lymphocyte reactions (MLR) in which stimulator cells or responder T cells were pretreated with either ONX 0914 or PR-825. MLR were conducted for the B10.BR anti-C56BL/6y (B6) MHC-mismatched, the CD8+ T cell-mediated B10.BR anti-CBA, and the CD4+ T cell-mediated B6 anti-BALB.B MHC-matched/ miHA-disparate strain combinations. Methods Stimulator splenocytes were treated for one hour with ONX 0914 (300 nM) or PR-825 (125 nM) before or immediately after exposure to irradiation (30 Gy) prior to initiation of the MLR. In addition, to try to optimize putative in vivo drug regimens, we determined the timing of release/degradation of antigenic peptides presented in the context of MHC-I. To this end, the MC57G fibrosarcoma cell line was transiently transfected with a GFP tagged SIINFEKL plasmid, cells were treated with different drug regimens and exposure times of ONX 0914 or PR-825, and monitored over 48 hours for surface expression of MHC-I presented SIINFEKL peptide using flow cytometry. Results ELISpot assays showed a statistically significant decrease in the number of IFN-g producing cells when stimulators (B6 splenocytes) were pretreated with ONX 0914 compared to pretreated responder (B10.BR) cells (60.21% vs. 1.75% respectively, p< 0.01). In the miHA disparate combinations, the percentage decrease in IFN-g+ spots was ∼30% when stimulators were treated with ONX 0914, whereas only a ∼15% decrease was observed with PR-825 pretreatment. Furthermore, IFN-g production was not dependent upon the timing of exposure to irradiation, as ELISpot counts were equally decreased when drug pretreatments were performed before irradiation or just after exposure. Antigenic peptide presentation was maximally decreased in transfected MC57G cells 48 h after treatment (i.e., SIINFEKL % in GFP+ MC57G cells treated with DMSO was equal to 83% vs. 76% when cells were exposed to ONX 0914 [300 nM, for 24 h]. This result suggests that for in vivo application, pretreatment of recipient mice with ONX 0914 to decrease miHA presentation by host cells (24-72 hours prior to bone marrow transplantation) may provide further amelioration of GVHD development. Conclusion Taken together, these data suggest that downregulation of LMP7-mediated presentation of MHC-I restricted antigens by host cells likely modulated stimulation and IFN-g production of donor T cells in vivo, rather than acting on effector cells directly, and accounted in part for the improved survival rate experienced by recipient mice treated with ONX 0914. Disclosures: Matos: Onyx Pharmaceuticals: Research Funding. Dziopa:Onyx Pharmaceuticals: Research Funding. Kirk:Onyx Pharmaceuticals: Employment. Korngold:Onyx Pharmaceuticals: Research Funding. Zilberberg:Onyx Pharmaceuticals: Research Funding.

scholarly journals Inhibition of nitric oxide production is associated with enhanced weight loss, decreased survival, and impaired alloengraftment in mice undergoing graft-versus-host disease after bone marrow transplantation

Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2363-2373 ◽  
Author(s):  
WR Drobyski ◽  
CA Keever ◽  
GA Hanson ◽  
T McAuliffe ◽  
OW Griffith
Keyword(s):  
Nitric Oxide ◽  
Bone Marrow ◽  
Weight Loss ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
No Production ◽  
Host Disease ◽  
Graft Versus Host

The pathophysiologic role of nitric oxide (NO) in graft-versus-host disease (GVHD) was investigated in a murine bone marrow (BM) transplantation model where donor and recipient were H-2-matched but differed at multiple minor histocompatibility antigens. Host AKR/J (H- 2K) mice received lethal total body irradiation as pretransplant conditioning followed by transplantation of donor B10.BR (H-2K) BM cells with or without spleen cells as a source of GVH-reactive T cells. NO production, as assessed by serum nitrate and nitrite levels, was increased for up to 3 weeks posttransplant in animals undergoing both moderate and severe GVHD. Administration of NG-methyl-L-arginine (L- NMA), an inhibitor of nitric oxide synthase, to animals undergoing GVHD resulted in effective suppression of NO production when compared with saline-treated GVHD control animals. Suppression of NO production by L- NMA in GVHD animals was associated with enhanced weight loss early posttransplant and decreased overall survival. Histologic analysis of tissues from L-NMA-treated and saline-treated GVHD animals showed that early weight loss was not because of an exacerbation of GVHD, indicating that NO did not appear to play an immunosuppressive role in this experimental model. L-NMA-treated animals with enhanced weight loss were observed to have splenic atrophy, decreased extramedullary hematopoiesis, and a reduction in BM cellularity when compared with GVHD control mice that were weight-matched before transplant. Analysis of T-cell chimerism in the spleen showed that L-NMA treatment impaired donor T-cell repopulation. In vitro colony-forming unit (CFU) assays were performed to further assess the role of NO on BM progenitor cell growth. L-NMA added directly into culture had no effect on CFU- granulocyte/macrophage (CFU-GM) formation in normal murine BM. In contrast, total CFU-GM from L-NMA-treated animals were significantly reduced when compared with GVHD controls or BM control animals who did not develop GVHD. Collectively, these data indicate that inhibition of NO impairs hematopoietic reconstitution and support the premise that NO appears to play a novel role in the facilitation of alloengraftment posttransplant.

scholarly journals Invariant Natural Killer T Cell Subsets Have Diverse Graft-Versus-Host-Disease-Preventing and Anti-Tumor Effects

Blood ◽  
2021 ◽  
Author(s):  
Kristina Maas-Bauer ◽  
Juliane K. Lohmeyer ◽  
Toshihito Hirai ◽  
Teresa Lopes Ramos ◽  
Furqan Muhammad Fazal ◽  
...  
Keyword(s):  
T Cell ◽  
Antitumor Activity ◽  
Natural Killer ◽  
Graft Versus Host Disease ◽  
Inkt Cells ◽  
Host Disease ◽  
Graft Versus Host ◽  
Invariant Natural Killer

Invariant Natural Killer T (iNKT) cells are a T cell subset with potent immunomodulatory properties. Experimental evidence in mice and observational studies in humans indicate that iNKT cells have antitumor potential as well as the ability to suppress acute and chronic Graft-versus-Host-Disease (GvHD). Murine iNKT cells differentiate during thymic development into iNKT1, iNKT2 and iNKT17 sublineages, which differ transcriptomically and epigenomically, and have subset-specific developmental requirements. Whether distinct iNKT sublineages also differ in their antitumor effect and their ability to suppress GvHD is currently unknown. In this work, we generated highly purified murine iNKT-sublineages, characterized their transcriptomic and epigenomic landscape, and assessed specific functions. We demonstrate that iNKT2 and iNKT17, but not iNKT1 cells, efficiently suppress T cell activation in vitro and mitigate murine acute GvHD in vivo. Conversely, we show that iNKT1 cells display the highest antitumor activity against murine B-cell lymphoma cells both in vitro and in vivo. Thus, we demonstrate for the first time that iNKT sublineages have distinct and different functions, with iNKT1 cells having the highest antitumor activity and iNKT2 and iNKT17 cells having immune-regulatory properties. These results have important implications for the translation of iNKT cell therapies to the clinic for cancer immunotherapy as well as for GvHD prevention and treatment.

scholarly journals Bone Marrow Regulatory T Cells Are a Unique Population, Supported by Niche-Specific Cytokines and Plasmacytoid Dendritic Cells, and Required for Chronic Graft-Versus-Host Disease Control

2021 ◽  
Vol 9 ◽  
Author(s):  
Jemma Nicholls ◽  
Benjamin Cao ◽  
Laetitia Le Texier ◽  
Laura Yan Xiong ◽  
Christopher R. Hunter ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
Chemokine Receptors ◽  
Cell Cycle Control ◽  
Plasmacytoid Dendritic Cells ◽  
Host Disease ◽  
Graft Versus Host

Regulatory T cell (Treg) reconstitution is essential for reestablishing tolerance and maintaining homeostasis following stem-cell transplantation. We previously reported that bone marrow (BM) is highly enriched in autophagy-dependent Treg and autophagy disruption leads to a significant Treg loss, particularly BM-Treg. To correct the known Treg deficiency observed in chronic graft-versus-host disease (cGVHD) patients, low dose IL-2 infusion has been administered, substantially increasing peripheral Treg (pTreg) numbers. However, as clinical responses were only seen in ∼50% of patients, we postulated that pTreg augmentation was more robust than for BM-Treg. We show that BM-Treg and pTreg have distinct characteristics, indicated by differential transcriptome expression for chemokine receptors, transcription factors, cell cycle control of replication and genes linked to Treg function. Further, BM-Treg were more quiescent, expressed lower FoxP3, were highly enriched for co-inhibitory markers and more profoundly depleted than splenic Treg in cGVHD mice. In vivo our data are consistent with the BM and not splenic microenvironment is, at least in part, driving this BM-Treg signature, as adoptively transferred splenic Treg that entered the BM niche acquired a BM-Treg phenotype. Analyses identified upregulated expression of IL-9R, IL-33R, and IL-7R in BM-Treg. Administration of the T cell produced cytokine IL-2 was required by splenic Treg expansion but had no impact on BM-Treg, whereas the converse was true for IL-9 administration. Plasmacytoid dendritic cells (pDCs) within the BM also may contribute to BM-Treg maintenance. Using pDC-specific BDCA2-DTR mice in which diptheria toxin administration results in global pDC depletion, we demonstrate that pDC depletion hampers BM, but not splenic, Treg homeostasis. Together, these data provide evidence that BM-Treg and splenic Treg are phenotypically and functionally distinct and influenced by niche-specific mediators that selectively support their respective Treg populations. The unique properties of BM-Treg should be considered for new therapies to reconstitute Treg and reestablish tolerance following SCT.

scholarly journals Inhibition of nitric oxide production is associated with enhanced weight loss, decreased survival, and impaired alloengraftment in mice undergoing graft-versus-host disease after bone marrow transplantation

Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2363-2373 ◽  
Author(s):  
WR Drobyski ◽  
CA Keever ◽  
GA Hanson ◽  
T McAuliffe ◽  
OW Griffith
Keyword(s):  
Nitric Oxide ◽  
Bone Marrow ◽  
Weight Loss ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
No Production ◽  
Host Disease ◽  
Graft Versus Host

Abstract The pathophysiologic role of nitric oxide (NO) in graft-versus-host disease (GVHD) was investigated in a murine bone marrow (BM) transplantation model where donor and recipient were H-2-matched but differed at multiple minor histocompatibility antigens. Host AKR/J (H- 2K) mice received lethal total body irradiation as pretransplant conditioning followed by transplantation of donor B10.BR (H-2K) BM cells with or without spleen cells as a source of GVH-reactive T cells. NO production, as assessed by serum nitrate and nitrite levels, was increased for up to 3 weeks posttransplant in animals undergoing both moderate and severe GVHD. Administration of NG-methyl-L-arginine (L- NMA), an inhibitor of nitric oxide synthase, to animals undergoing GVHD resulted in effective suppression of NO production when compared with saline-treated GVHD control animals. Suppression of NO production by L- NMA in GVHD animals was associated with enhanced weight loss early posttransplant and decreased overall survival. Histologic analysis of tissues from L-NMA-treated and saline-treated GVHD animals showed that early weight loss was not because of an exacerbation of GVHD, indicating that NO did not appear to play an immunosuppressive role in this experimental model. L-NMA-treated animals with enhanced weight loss were observed to have splenic atrophy, decreased extramedullary hematopoiesis, and a reduction in BM cellularity when compared with GVHD control mice that were weight-matched before transplant. Analysis of T-cell chimerism in the spleen showed that L-NMA treatment impaired donor T-cell repopulation. In vitro colony-forming unit (CFU) assays were performed to further assess the role of NO on BM progenitor cell growth. L-NMA added directly into culture had no effect on CFU- granulocyte/macrophage (CFU-GM) formation in normal murine BM. In contrast, total CFU-GM from L-NMA-treated animals were significantly reduced when compared with GVHD controls or BM control animals who did not develop GVHD. Collectively, these data indicate that inhibition of NO impairs hematopoietic reconstitution and support the premise that NO appears to play a novel role in the facilitation of alloengraftment posttransplant.

scholarly journals Microrna-191 Regulates T-Cell Clonal Expansion during Graft-Versus-Host Disease

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4433-4433
Author(s):  
Chuanfeng Xiong ◽  
Wei Huang ◽  
Xiaoli Nie ◽  
Ying Huang ◽  
Yiqun Jiao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
Clonal Expansion ◽  
Host Disease ◽  
Graft Versus Host ◽  
Alloreactive T Cells

Allogeneic hematopoietic cell transplantation is a potentially curative treatment choice for a wide variety of hematological malignancies. However, graft-versus-host disease (GVHD), which is mediated by donor alloreactive T cells, limits the success of this procedure. Previous studies have demonstrated that several microRNAs (miRs) modulate graft-versus-host disease. miR-191 was previously reported to be able to support T cell survival after TCR stimulation. We hypothesize that miR191 regulates T cell response during GVHD. To test this hypothesis, we first studied miR-191 expression in alloreactive T cells. The result demonstrated that miR-191 was up-regulated in donor T cells isolated from murine GVHD recipients, suggesting that miR-191 may play a role in GVHD induction. We further studied the role of miR-191in GVHD using miR-191 deficient T cells (KO). Lethally irradiated (8.5 Gy) BALB/c mice were injected intravenously with 1×107 T cell-depleted bone marrow (TCDBM) cells along with 1×106 purified T cells from wild-type (WT) or KO mice, which are in C57BL/6 background. Interestingly, all recipients in the WT group died within 35 days after transplantation, while only one out of ten animals died in the KO group during an observation period of 56 days. Body weights and clinical scores were also improved in KO T cell recipients when compared with the WT controls. Similar results were also observed in a second GVHD model (C57BL/6→C3H/HeJ). To understand the mechanism by which miR-191 KO T cells have decreased ability to mediate GVHD, we first measured the ability of KO T cells to respond to alloantigens in vitro in a mixed lymphocytes reaction assay. Dramatically decreased alloresponse was observed with KO T cells as compared with WT T cells. Similarly, decreased clonal expansion was observed in KO T cells in vivo upon challenge with alloantigens as measured by bioluminescent imaging (Figure 1A). These results were further supported by data from a co-transfer experiment, in which equal numbers of WT and KO T cells were transplanted into the same GVHD recipient. At day7 after transplantation, KO T cells showed significantly reduced expansion in the spleen and liver compared with WT T cells. Reduced alloresponses mediated by KO T cells may not due to decreased proliferative capability directly as an in vivo carboxyfluorescein succinimidyl ester (CFSE) assay showed a comparable cell division between WT and KO T cells upon challenge with alloantigens. Rather, increased cell death is responsible for decreased alloresponse observed in KO T cells because dramatically increased number of dead cells was observed in KO group compared with WT group upon response to alloantigens in vitro and vivo. To determine the genes that are regulated by miR-191, we did a screening based on the prediction. Humans and mice share more than 100 predicted targets for miR-191. We chose top 20 of these targets for RT-qPCR screening. The result demonstrated that Taf5 was a target gene of miR-191. Expression of TAF5 protein was down-regulated in activated KO T cells when compared with the WT T cells. Finally, we investigated whether miR-191 KO T cells preserve graft-versus-leukemia effects. 1×106 T cells from WT or KO mice were transplanted into lethally irradiated BALB/c mice along with 1×107 TCDBM cells and 1×105 host-type BCL-1 cells. While all recipients that received only TCDBM and tumor cells developed lethal leukemia/lymphoma, none of WT and KO T cells recipients developed tumor. In conclusion, our findings reveal a critical role of miR-191 during GVHD process and demonstrate that miR-191 is a novel therapeutic target for GVHD. Figure 1 Disclosures No relevant conflicts of interest to declare.

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