Critical Role of the Th1 Transcription Factor T-Bet in An Animal Model of Immune-Mediated Bone Marrow Failure

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1037-1037
Author(s):  
Yong Tang ◽  
Jichun Chen ◽  
Neal Young
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cd8 T Cells ◽  
Bone Marrow Failure ◽  
Critical Role ◽  
Wild Type ◽  
Immune Mediated ◽  
Ifn Γ ◽  
Th1 Immune Response

Abstract Patients with aplastic anemia have elevated T-bet, a Th1 transcription factor, in peripheral blood CD4 and CD8 T cells, suggesting that T-bet over-expression and dysregulated Th1 immune response contributes to pathophysiology of marrow failure (Solomou EE et al., Blood. 2006; 107:3983). In the present study, we studied the role of T-bet in inducing bone marrow failure in a mouse model of immune-mediated BM failure, employing mice engineered with a germline T-bet deletion as lymphocyte donors. Compared with T-bet +/+ wild-type controls, T-bet−/− mice have similar cellular composition in various lymphohematopietic tissues including peripheral blood, spleen, thymus, lymph nodes (LN), and BM. Incubation of effector T-bet−/− LN cells with MHC-mismatched target CByB6F1 (F1) BM cells in an in vitro cytotoxicity assay resulted in a significantly lower proportion of apoptotic target cells than did wild-type T-bet+/+ LN effector cells, suggesting that T-bet−/− effector LN cells are functionally defective. While infusion of 5×106 wild-type T-bet+/+ LN cells into sublethally-irradiated F1 mice led to severe pancytopenia and aplastic bone marrow in recipient mice, infusion of the same number of T-bet−/− LN cells failed to result in marrow failure, and recipients had relatively normal blood counts and bone marrow cellularity. By flow cytometry, both expansion of CD4+ and CD8+ T cells and elevation in intracellular Th1 cytokine gamma interferon (IFN-γ), which are characteristic of marrow cells in recipients received B6 LN cells, were absent in recipients receiving T-bet −/− LN cells. Serum IFN-γ concentration in F1 mice infused with T-bet −/− LN cells was similar to the level in F1 control mice received TBI alone, and both were significantly lower than serum IFN-γ in recipients of wild-type B6 LN cells. In contrast, serum TGF-γ concentration was higher in F1 mice that received TBI alone or TBI plus T-bet −/− LN cell infusion, compared with mice that received TBI plus B6 LN cells. An increase of T-bet −/− LN cell infusion to 10×106 cells per recipient led to very mild BM failure. Contrary to the markedly increased number of CD4+ and CD8+ T cells and elevated IFN-γ level in the BM of F1 mice which have received wild type B6 LN cells, F1 mice infused with T-bet −/− LN have low CD4+ and CD8+ cells and low IFN-γ level in the BM similar to F1 mice received TBI alone, but they show increased IL4 and IL17 levels within bone marrow T cells, indicating that the diminished Th1 immune response due to T-bet deficiency was partially compensated by up-regulated Th2 and Th17 responses. Our data demonstrated that T-bet plays a critical role in immune mediated bone marrow failure. Approaches targeting to T-bet signal pathway may lead to novel treatment for bone marrow failure and other autoimmune diseases.

scholarly journals The role of the Th1 transcription factor T-bet in a mouse model of immune-mediated bone-marrow failure

Blood ◽  
2010 ◽  
Vol 115 (3) ◽  
pp. 541-548 ◽  
Author(s):  
Yong Tang ◽  
Marie J. Desierto ◽  
Jichun Chen ◽  
Neal S. Young
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Transcription Factor ◽  
Transforming Growth Factor ◽  
Bone Marrow Failure ◽  
Critical Role ◽  
Interferon Γ ◽  
Interleukin 17 ◽  
Immune Mediated

Abstract The transcription factor T-bet is a key regulator of type 1 immune responses. We examined the role of T-bet in an animal model of immune-mediated bone marrow (BM) failure using mice carrying a germline T-bet gene deletion (T-bet−/−). In comparison with normal C57BL6 (B6) control mice, T-bet−/− mice had normal cellular composition in lymphohematopoietic tissues, but T-bet−/− lymphocytes were functionally defective. Infusion of 5 × 106 T-bet−/− lymph node (LN) cells into sublethally irradiated, major histocompatibility complex–mismatched CByB6F1 (F1) recipients failed to induce the severe marrow hypoplasia and fatal pancytopenia that is produced by injection of similar numbers of B6 LN cells. Increasing T-bet−/− LN-cell dose to 10 to 23 × 106 per recipient led to only mild hematopoietic deficiency. Recipients of T-bet−/− LN cells had no expansion in T cells or interferon-γ–producing T cells but showed a significant increase in Lin−Sca1+CD117+CD34− BM cells. Plasma transforming growth factor-β and interleukin-17 concentrations were increased in T-bet−/− LN-cell recipients, possibly a compensatory up-regulation of the Th17 immune response. Continuous infusion of interferon-γ resulted in hematopoietic suppression but did not cause T-bet−/− LN-cell expansion or BM destruction. Our data provided fresh evidence demonstrating a critical role of T-bet in immune-mediated BM failure.

scholarly journals The critical role of T cells in glucocorticoid-induced osteoporosis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Lin Song ◽  
Lijuan Cao ◽  
Rui Liu ◽  
Hui Ma ◽  
Yanan Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Steady State ◽  
Side Effects ◽  
Critical Role ◽  
Wild Type ◽  
Receptor Activator ◽  
Steady State Levels ◽  
Induced Apoptosis

AbstractGlucocorticoids (GC) are widely used clinically, despite the presence of significant side effects, including glucocorticoid-induced osteoporosis (GIOP). While GC are believed to act directly on osteoblasts and osteoclasts to promote osteoporosis, the detailed underlying molecular mechanism of GC-induced osteoporosis is still not fully elucidated. Here, we show that lymphocytes play a pivotal role in regulating GC-induced osteoporosis. We show that GIOP could not be induced in SCID mice that lack T cells, but it could be re-established by adoptive transfer of splenic T cells from wild-type mice. As expected, T cells in the periphery are greatly reduced by GC; instead, they accumulate in the bone marrow where they are protected from GC-induced apoptosis. These bone marrow T cells in GC-treated mice express high steady-state levels of NF-κB receptor activator ligand (RANKL), which promotes the formation and maturation of osteoclasts and induces osteoporosis. Taken together, these findings reveal a critical role for T cells in GIOP.

A Critical Role for Innate Immunity In Allogeneic Hematopoietic Cell Rejection Via the TLR4/TRIF Pathway

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 77-77
Author(s):  
Hong Xu ◽  
Jun Yan ◽  
Ziqiang Zhu ◽  
Yiming Huang ◽  
Yujie Wen ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Innate Immunity ◽  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Innate Immune System ◽  
Critical Role ◽  
Innate Immune ◽  
Wild Type

Abstract Abstract 77 Adaptive immunity, especially T cells, has long been believed to be the dominant immune barrier in allogeneic transplantation. Targeting host T cells significantly reduces conditioning for bone marrow cell (BMC) engraftment. Innate immunity has been recently shown to pose a significant barrier in solid organ transplantation, but has not been addressed in bone marrow transplantation (BMT). Using T cell deficient (TCR-β/δ−/−) or T and B cell deficient (Rag−/−) mice, we found that allogeneic BMC rejection occurred early before the time required for T cell activation and was T- and B-cell independent, suggesting an effector role for innate immune cells in BMC rejection. Therefore, we hypothesized that by controlling both innate and adaptive immunity, the donor BMC would have a window of advantage to engraft. Survival of BMC in vivo was significantly improved by depleting recipient macrophages and/or NK cells, but not neutrophils. Moreover, depletion of macrophages and NK cells in combination with co-stimulatory blockade with anti-CD154 and rapamycin as a novel form of conditioning resulted in 100% allogeneic engraftment without any irradiation and T cell depletion. Donor chimerism remained stable and durable up to 6 months. Moreover, specific Vβ5½ and Vβ11 clonal deletion was detected in host CD4+ T cells in chimeras, indicating central tolerance to donor alloantigens. Whether and how the innate immune system recognizes or responds to allogeneic BMCs remains unknown. Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. The signaling function of TLR depends on intracellular adaptors. The adaptor MyD88 transmits signals emanating from all TLR, except TLR3 while TRIF specifically mediates TLR3 and TLR4 signaling via type 1 IFN. To further determine the innate signaling pathways in allogeneic BMC rejection, B6 background (H2b) MyD88−/− and TRIF−/− mice were conditioned with anti-CD154/rapamycin plus 100 cGy total body irradiation and transplanted with 15 × 106 BALB/c (H2d) BMC. Only 33.3% of MyD88−/− recipients engrafted at 1 month, resembling outcomes for wild-type B6 mice. In contrast, 100% of TRIF−/− mice engrafted. The level of donor chimerism in TRIF−/− mice was 5.1 ± 0.6% at one month, significantly higher than in MyD88−/− and wild-type B6 controls (P < 0.005). To determine the mechanism of innate signaling in BMC rejection, we examined whether TRIF linked TLR3 or TLR4 is the key pattern recognition receptor involved in BMC recognition. To this end, TLR3−/− and TLR4−/− mice were transplanted with BALB/c BMC with same conditioning. None of the TLR3−/− mice engrafted. In contrast, engraftment was achieved in 100% of TLR4−/− mice up to 6 months follow up. Taken together, these results suggest that rejection of allogeneic BMC is uniquely dependent on the TLR4/TRIF signaling pathway. Thus, our results clearly demonstrate a previously unappreciated role for innate immunity in allogeneic BMC rejection. Our current findings are distinct from prior reports demonstrating a critical role of MyD88 in rejection of allogeneic skin grafts and lung, and may reflect unique features related to BMC. The findings of the role of innate immunity in BMC rejection would lead to revolutionary changes in our understanding and management of BMT. This would be informative in design of more specific innate immune targeted conditioning proposals in BMT to avoid the toxicity. Disclosures: Bozulic: Regenerex LLC: Employment. Ildstad:Regenerex LLC: Equity Ownership.

scholarly journals Effector CD8+ T Lymphocytes against Liver Stages of Plasmodium yoelii Do Not Require Gamma Interferon for Antiparasite Activity

2008 ◽  
Vol 76 (8) ◽  
pp. 3628-3631 ◽  
Author(s):  
Sumana Chakravarty ◽  
G. Christian Baldeviano ◽  
Michael G. Overstreet ◽  
Fidel Zavala
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protective Immunity ◽  
Critical Role ◽  
Plasmodium Yoelii ◽  
Gamma Interferon ◽  
Parasite Development ◽  
Wild Type ◽  
Ifn Γ

ABSTRACT The protective immune response against liver stages of the malaria parasite critically requires CD8+ T cells. Although the nature of the effector mechanism utilized by these cells to repress parasite development remains unclear, a critical role for gamma interferon (IFN-γ) has been widely assumed based on circumstantial evidence. However, the requirement for CD8+ T-cell-mediated IFN-γ production in protective immunity to this pathogen has not been directly tested. In this report, we use an adoptive transfer strategy with circumsporozoite (CS) protein-specific transgenic T cells to examine the role of CD8+ T-cell-derived IFN-γ production in Plasmodium yoelii-infected mice. We show that despite a marginal reduction in the expansion of naive IFN-γ-deficient CS-specific transgenic T cells, their antiparasite activity remains intact. Further, adoptively transferred IFN-γ-deficient CD8+ T cells were as efficient as their wild-type counterparts in limiting parasite growth in naive mice. Taken together, these studies demonstrate that IFN-γ secretion by CS-specific CD8+ T cells is not essential to protect mice against live sporozoite challenge.

Characterization of pathogenic CD8 + T cells in Chlamydia - infected OT1 mice

2021 ◽  
Author(s):  
Zengzi Zhou ◽  
Qi Tian ◽  
Luying Wang ◽  
Xin Sun ◽  
Nu Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
Chlamydia Trachomatis ◽  
Cd8 T Cells ◽  
Chlamydial Infection ◽  
Critical Role ◽  
Wild Type ◽  
Chlamydia Muridarum ◽  
Time Of Infection

Chlamydia trachomatis is a leading infectious cause of infertility in women due to its induction of lasting pathology such as hydrosalpinx. Chlamydia muridarum induces mouse hydrosalpinx because C. muridarum can both invade tubal epithelia directly (as a 1 st hit) and induce lymphocytes to promote hydrosalpinx indirectly (as a 2 nd hit). In the current study, a critical role of CD8 + T cells in chlamydial induction of hydrosalpinx was validated in both wild type C57BL/6J and OT1 transgenic mice. OT1 mice failed to develop hydrosalpinx partially due to the failure of their lymphocytes to recognize chlamydial antigens. CD8 + T cells from naïve C57BL/6J rescued the recipient OT1 mice to develop hydrosalpinx when naïve CD8 + T cells were transferred at the time of infection with Chlamydia . However, when the transfer was delayed for 2 weeks or longer after the chlamydial infection, naïve CD8 + T cells no longer promoted hydrosalpinx. Nevertheless, Chlamydia -immunized CD8 + T cells still promoted significant hydrosalpinx in the recipient OT1 mice even when the transfer was delayed for 3 weeks. Thus, CD8 + T cells must be primed within 2 weeks after chlamydial infection to be pathogenic but once primed, they can promote hydrosalpinx for >3 weeks. However, Chlamydia -primed CD4 + T cells failed to promote chlamydial induction of pathology in OT1 mice. This study has optimized an OT1 mouse-based model for revealing the pathogenic mechanisms of Chlamydia -specific CD8 + T cells.

scholarly journals Granulocytic Myeloid-Derived Suppressor Cells in Murine Models of Immune-Mediated Bone Marrow Failure

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2176-2176
Author(s):  
Xingmin Feng ◽  
Jisoo Kim ◽  
Gladys Gonzalez Matias ◽  
Zhijie Wu ◽  
Sabrina Solorzano ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Bone Marrow Failure ◽  
Suppressor Cells ◽  
T Cell Proliferation ◽  
Immune Mediated

Abstract Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of immature myeloid cells with immunoregulatory function. Limited published studies have reported conflicting data concerning the effects of MDSCs on autoimmune diseases and graft-versus-host disease. MDSCs can be divided into two major subsets, more abundant granulocytic (G-MDSCs) and monocytic (M-MDSCs). We examined G-MDSCs in murine models of human bone marrow failure (BMF). We first characterized bone marrow (BM) MDSCs from C.B10 mice. CD11b +Ly6G +Ly6C low G-MDSCs suppressed in vitro proliferation of both CD4 and CD8 T cells from C57BL/6 (B6) mice, while Ly6G +Ly6C - cells had no effect and Ly6G -Ly6C + cells increased T cell proliferation (Fig. 1A). We then tested G-MDSCs in vivo utilizing antibody-mediated cell depletion. Lymph node (LN) cells from B6 donor mice were injected into sub-lethally irradiated major histocompatibility-mismatched CByB6F1 mice to induce BMF. Anti-Ly6G antibody injection worsened cytopenias and BM hypoplasia, and they increased BM CD4 and CD8 T cell infiltration. In contrast, anti-Ly6G antibody injection in the minor histocompatibility-mismatched C.B10 BMF model improved platelet counts and reduced BM CD8 T cells. The pathogenic and protective effects in the two models correlated with differential anti-Ly6G antibody modulation of G-MDSCs: in the CByB6F1 model, anti-Ly6G antibody eradicated G-MDSCs in blood and BM while in the C.B10 model the same antibody generated a novel G-MDSC cell population, of identical Ly6C lowCD11b + phenotype but intermediate Ly6G expression, which was not present in the CByB6F1 animals after antibody injection. When we examined the efficacy of G-MDSCs in C.B10 BMF: Ly6G + cells were enriched from BM of normal C.B10 donors (94%-97% Ly6C lowLy6G +CD11b +), and injected at the time of marrow failure initiation. Mice infused with Ly6G + cells had significantly higher levels of WBC, RBC, platelets, and total BM cells, decreased BM CD4 and CD8 T cell infiltration, and improved BM cellularity. These results indicated a protective role of G-MDSCs. When G-MDSCs were injected at day 3 after LN cell infusion, treated mice again had higher levels of WBC, RBC, platelets, and total BM cells at day 14, alleviating BMF. As both prophylaxis and therapy, G-MDSCs decreased Fas expression and Annexin V binding of residual BM cells, suppressed intracellular levels of gamma interferon and tumor necrosis factor alpha, as well as cell proliferation protein Ki67 levels in BM CD4 and CD8 T cells, relative to BMF control mice. TotalSeq simultaneously detecting surface proteins and mRNA expression in whole BM mononuclear cells in the therapy model showed an increased proportion of myeloid cells and reduced proportion of T cells in marrow from G-MDSC-treated mice based on cell surface markers and marker gene expression (Fig. 1B). Gene pathway analysis revealed down-regulation of Fas expression and reduced program cell death in total BM cells and decreased expression of genes related to cell cycle in infiltrating T cells from Ly6G + cell-treated mice-both results consistent with suppression by G-MDSCs of T cell proliferation and protection of target BM cells from apoptosis. In vitro culture of T cells from B6 mice with G-MDSCs which had been isolated from C.B10 BM cells showed dose-dependent suppression of T cell proliferation. In conclusion, our results demonstrate an active role of G-MDSCs in protecting BM from immune-mediated destruction, by suppression of T cell proliferation in the BM. G-MDSCs might have clinical application as treatment in human aplastic anemia and other immune-mediated and autoimmune diseases. Figure 1 Figure 1. Disclosures Young: Novartis: Research Funding.

A Murine Model of Bone Marrow Failure Mediated by Disparity in Minor Histocompatibility Antigens.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 132-132
Author(s):  
Jichun Chen ◽  
Neal S. Young
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Lymph Node ◽  
Aplastic Anemia ◽  
Cd8 T Cells ◽  
Bone Marrow Failure ◽  
Histocompatibility Antigens ◽  
Minor Histocompatibility Antigens ◽  
Immune Mediated ◽  
Lymph Node Cells

Abstract Destruction of hematopoietic cells in aplastic anemia and other hematologic diseases is mediated in most patients by effector cells of the immune system. We have developed a mouse model of immune-mediated bone marrow failure which employs parental lymph node cell infusion into F1 recipients, resulting in bone marrow hypercellularity, pancytopenia, and death from infection and bleeding, without other organ involvement by graft-versus-host disease (Bloom, ML et al. Exp. Hematol. 32:1163, 2004; Chen, J et al. Blood104:1671, 2004). Because major histocompatibility antigens are not the targets in acquired aplastic anemia, we now have developed a model of murine marrow failure based on disparity of minor histocompatibility antigens. Lymph node cells from C57BL/6 mice were infused into sublethally-irradiated, MHC-matched, C.B10-H2b/LilMce recipients. Animals developed severe pancytopenia and marrow hypoplasia within two-three weeks. CD8+ T lymphocytes were expanded in the blood and infiltrated bone marrow, becoming detectable at day 7 and reaching peak levels at days 10–12. There were no inflammatory responses observed in the skin, intestines, or other visceral organs by gross or microscopic pathological examination. In our experiments we observed a time-dependent expansion followed by contraction of CD8+ T cells specific for a minor histocompatibility antigen H60 as measured by flowcytometry using an H60-specific tetramer. H60 is an antigen peptide derived from a glycoprotein, a known ligand for stimulatory NKG2D receptors, and is immunodominant over other minor antigens in stem cell transplantation. The proportion of H60-specific CD8+ T cells was strongly negatively correlated with peripheral blood white cell, neutrophil, and platelet counts. Isolated H60-specific T-cells from bone marrow of affected animals induced apoptosis in vitro of normal C57BL/6 bone marrow cells in co-culture. The degree of apoptosis was further increased by addition of CD4 T-cells from same affected donors, suggesting a helper lymphocyte effect. The role of H60-specific T cells was demonstrated in further transplant experiments. Infusion of 5 × 106 C57BL/6 lymph node cells that had been depleted of H60-specific T cells was unable to induce marrow failure in C.B10 recipients, while the same number of cells with the addition of 20–90 × 103 H60-specific CD8+ T cells led to thrombocytopenia and leucopenia in recipients. H60-specific T cells thus appear to be key effectors, responsible at least for the initiation of marrow cell destruction. Mice could be treated with cyclosporine at 50 mg/g/day for five days, if treatments were begun at the time of lymph node cell infusion. Immunosuppressive therapy abolished H60-specific CD8+ T cell expansion and attenuated the development of peripheral pancytopenia, effectively rescuing animals. In conclusion, we demonstrate in this model of immune-mediated bone marrow failure that a single clone of peptide-specific T-cells is capable of efficient marrow destruction and the production of aplastic anemia.

Aplastic anaemia and pure red cell aplasia

2010 ◽  
pp. 4297-4298
Author(s):  
Judith C.W. Marsh ◽  
Austin Kulasekararaj ◽  
Ghulam J. Mufti
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Immunosuppressive Therapy ◽  
Aplastic Anaemia ◽  
Cd8 T Cells ◽  
Bone Marrow Failure ◽  
Treatment Options ◽  
Pure Red Cell Aplasia ◽  
Red Cell Aplasia ◽  
Immune Mediated

Aplastic anaemia (AA) is a rare bone marrow failure (BMF) disorder characterized by pancytopenia and a hypocellular bone marrow. AA is commonly acquired, immune-mediated and idiopathic in nature. Activate auto-reactive, cytotxic CD8+ T-cells are present but recent work has shown that CD4+ T-cells appear to be more important in the pathogenesis of acquired AA. The immune nature of acquired AA provides the rationale for one of the treatment options, namely immunosuppressive therapy....

scholarly journals Macrophage TNF-α licenses donor T cells in murine bone marrow failure and can be implicated in human aplastic anemia

Blood ◽  
2018 ◽  
Vol 132 (26) ◽  
pp. 2730-2743 ◽  
Author(s):  
Wanling Sun ◽  
Zhijie Wu ◽  
Zenghua Lin ◽  
Maile Hollinger ◽  
Jichun Chen ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Aplastic Anemia ◽  
Bone Marrow Failure ◽  
Murine Bone Marrow ◽  
Immune Mediated ◽  
Tnf Α ◽  
Donor T Cells ◽  
Ifn Γ

Abstract Interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) have been implicated historically in the immune pathophysiology of aplastic anemia (AA) and other bone marrow (BM) failure syndromes. We recently defined the essential roles of IFN-γ produced by donor T cells and the IFN-γ receptor in the host in murine immune-mediated BM failure models. TNF-α has been assumed to function similarly to IFN-γ. We used our murine models and mice genetically deficient in TNF-α or TNF-α receptors (TNF-αRs) to establish an analogous mechanism. Unexpectedly, infusion of TNF-α−/− donor lymph node (LN) cells into CByB6F1 recipients or injection of FVB LN cells into TNF-αR−/− recipients both induced BM failure, with concurrent marked increases in plasma IFN-γ and TNF-α levels. Surprisingly, in TNF-α−/− recipients, BM damage was attenuated, suggesting that TNF-α of host origin was essential for immune destruction of hematopoiesis. Depletion of host macrophages before LN injection reduced T-cell IFN-γ levels and reduced BM damage, whereas injection of recombinant TNF-α into FVB-LN cell-infused TNF-α−/− recipients increased T-cell IFN-γ expression and accelerated BM damage. Furthermore, infusion of TNF-αR−/− donor LN cells into CByB6F1 recipients reduced BM T-cell infiltration, suppressed T-cell IFN-γ production, and alleviated BM destruction. Thus, TNF-α from host macrophages and TNF-αR expressed on donor effector T cells were critical in the pathogenesis of murine immune-mediated BM failure, acting by modulation of IFN-γ secretion. In AA patients, TNF-α–producing macrophages in the BM were more frequent than in healthy controls, suggesting the involvement of this cytokine and these cells in human disease.

scholarly journals The IL-27/Wsx-1 Axis Modulates T Cell Responses and Regulates Acute Graft-Versus-Host Disease after Allogeneic Bone Marrow Transplantation

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2146-2146
Author(s):  
Shoubao Ma ◽  
Huanle Gong ◽  
Shuangzhu Liu ◽  
Jingjing Han ◽  
Zhinan Yin ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cd8 T Cells ◽  
Acute Gvhd ◽  
Treg Cells ◽  
Graft Versus Host ◽  
Cell Responses ◽  
Target Organs ◽  
Ifn Γ

Abstract IL-27 is a member of the IL-12 cytokine family that consists of EBV-induced gene 3 (EBI3), and p28. IL-27 is produced by activated antigen-presenting cells such as dendritic cells (DCs) and macrophages, and it signals through a heterodimeric receptor (IL-27R) consisting of the WSX-1 and the gp130. Emerging evidence has shown that IL-27 has both pro- and anti-Inflammatory effects. Recent study demonstrated a protected role IL-27p28 in acute graft-versus-host disease (aGVHD) in parent-to-F1 murine aGVHD model (Marillier et al., Eur. J. Immunol. 2014). However, the precise role of IL-27 in the development of aGVHD remains largely unknown. In this study, we carried out studies in a murine aGVHD model of fully MHC-mismatched myeloablative bone marrow transplantation (C57BL/6 to BALB/c). Lethally irradiated BALB/c mice transplanted with WT B6 bone marrow (BM) plus IL-27-/-(IL-27p28flox/flox-CD11c-cre (Itgax-p28f/f)) splenocytes had significantly accelerated aGVHD mortality comparing with those received WT BM plus splenocytes (P<0.001). However, similar aGVHD mortality was observed between mice transplanted with WT BM plus WT splenocytes and IL-27-/-BM plus WT splenocytes, and IL-27-/-BM plus IL-27-/- splenocytes, suggesting that IL-27 from splenocytes, not BM-derived cells, had protective effect in aGVHD. Additionally, mice were transplanted with IL-27-/- BM and splenocytes, and then treated with rmIL-27 on days 0 and 7 post BMT. rmIL-27 treated mice had longer survival and alleviated the clinical signs of aGVHD compared to PBS-treated mice (P<0.05). We next explored the mechanisms by which IL-27 protects mice against aGVHD. We found the expression of the cell surface IL-27 receptor, WSX-1 and gp130, were increased on both CD4+ and CD8+T cells after allo-stimulation. Moreover, IL-27 inhibited cell proliferation of allo-reactive T cells in mix lymphocytes reactivation (MLR) in vitro. We also found that the percentages of CD69+CD4+, CD69+CD8+T cells, as well as IFN-γ expression by CD4+ and CD8+T, were significantly increased in the spleen, liver and intestinal intraepithelial lymphocytes (IEL) from mice transplanted with WT BM and IL-27-/- splenocytes. Furthermore, we observed increased frequencies and numbers of Treg cells and MDSCs in aGVHD target organs in mice reconstituted with IL-27-/-splenocytes. Together, these results indicated that IL-27 alleviated aGVHD may through suppressing Th1 cell responses and promoting immune suppressing cells, including MDSCs and Treg cells. To further clarify the role of IL-27 in aGVHD, mice were transplanted with WT BM plus IL-27R-/-(B6N.129P2-Il27ratm1Mak/J) splenocytes, the results, however, showed that IL-27R deficiency in donor T cells significantly attenuated aGVHD, which was unpredicted, and was contrary to that of IL-27 deficiency results. Additional studies showed that IL-27R deficiency in T cells inhibited allo-reactive T cells proliferation and IL-2, IFN-γ production in MLR assay. The percentages of CD69+ T cells and IFN-γ+ CD4+ and CD8+T were significantly decreased, while the MDSCs and Treg cells wereincreased in aGVHD target organs from mice transplanted IL-27R-/-splenocytes. These results indicated that lack of IL-27R signaling resulted in downregulation of intrinsic immune responses which led to alleviation of aGVHD. Previous study reported that soluble form of IL-27Ra is highly existed in human serum and may severs as a natural IL-27 antagonist (Dietrich et al., JI. 2014). We hypothesized that sIL-27Ra may function as a decoy receptor to regulate aGVHD through inhibiting IL-27 signaling. To test this hypothesis, WT recipients were given exogenous soluble mouse IL-27 Ra Fc chimera protein known to block the binding of IL-27 to the membrane bound form of IL-27R. WT recipients given IL-27 Ra-Fc to block IL-27R/IL-27 interaction had significantly exacerbated GVHD mortality. The percentages of CD69+ T cells and IFN-γ+ CD4+ and CD8+T were significantly increased in aGVHD target organs from mice received IL-27 Ra fusion protein. In conclusion, this is the first demonstration in the same allogeneic BMT model that IL-27 deficiency augments but IL-27R deficiency alleviates acute GVHD. Our studies provide further evidence for the protective role of rmIL-27, and promoting effect of sIL-27R in the same aGVHD model. This study warrants further investigations of the possible therapeutic applications of IL-27 in acute GVHD. Disclosures No relevant conflicts of interest to declare.

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