scholarly journals MALT1 Controls Attenuated Rabies Virus by Inducing Early Inflammation and T Cell Activation in the Brain

2018 ◽  
Vol 92 (8) ◽  
Author(s):  
E. Kip ◽  
J. Staal ◽  
L. Verstrepen ◽  
H. G. Tima ◽  
S. Terryn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Virus Infection ◽  
Rabies Virus ◽  
T Cell Activation ◽  
Therapeutic Target ◽  
Cell Activation ◽  
Wild Type ◽  
The Impact ◽  
The Brain

ABSTRACTMALT1 is involved in the activation of immune responses, as well as in the proliferation and survival of certain cancer cells. MALT1 acts as a scaffold protein for NF-κB signaling and a cysteine protease that cleaves substrates, further promoting the expression of immunoregulatory genes. Deregulated MALT1 activity has been associated with autoimmunity and cancer, implicating MALT1 as a new therapeutic target. Although MALT1 deficiency has been shown to protect against experimental autoimmune encephalomyelitis, nothing is known about the impact of MALT1 on virus infection in the central nervous system. Here, we studied infection with an attenuated rabies virus, Evelyn-Rotnycki-Abelseth (ERA) virus, and observed increased susceptibility with ERA virus in MALT1−/−mice. Indeed, after intranasal infection with ERA virus, wild-type mice developed mild transient clinical signs with recovery at 35 days postinoculation (dpi). Interestingly, MALT1−/−mice developed severe disease requiring euthanasia at around 17 dpi. A decreased induction of inflammatory gene expression and cell infiltration and activation was observed in MALT1−/−mice at 10 dpi compared to MALT1+/+infected mice. At 17 dpi, however, the level of inflammatory cell activation was comparable to that observed in MALT1+/+mice. Moreover, MALT1−/−mice failed to produce virus-neutralizing antibodies. Similar results were obtained with specific inactivation of MALT1 in T cells. Finally, treatment of wild-type mice with mepazine, a MALT1 protease inhibitor, also led to mortality upon ERA virus infection. These data emphasize the importance of early inflammation and activation of T cells through MALT1 for controlling the virulence of an attenuated rabies virus in the brain.IMPORTANCERabies virus is a neurotropic virus which can infect any mammal. Annually, 59,000 people die from rabies. Effective therapy is lacking and hampered by gaps in the understanding of virus pathogenicity. MALT1 is an intracellular protein involved in innate and adaptive immunity and is an interesting therapeutic target because MALT1-deregulated activity has been associated with autoimmunity and cancers. The role of MALT1 in viral infection is, however, largely unknown. Here, we study the impact of MALT1 on virus infection in the brain, using the attenuated ERA rabies virus in different models of MALT1-deficient mice. We reveal the importance of MALT1-mediated inflammation and T cell activation to control ERA virus, providing new insights in the biology of MALT1 and rabies virus infection.

scholarly journals A role for CD9 molecules in T cell activation.

1996 ◽  
Vol 184 (2) ◽  
pp. 753-758 ◽  
Author(s):  
X G Tai ◽  
Y Yashiro ◽  
R Abe ◽  
K Toyooka ◽  
C R Wood ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
Expression Cloning ◽  
Wild Type ◽  
Almost All ◽  
Antigen Presenting ◽  
Deficient Mice

Costimulation mediated by the CD28 molecule plays an important role in optimal activation of T cells. However, CD28-deficient mice can mount effective T cell-dependent immune responses, suggesting the existence of other costimulatory systems. In a search for other costimulatory molecules on T cells, we have developed a monoclonal antibody (mAb) that can costimulate T cells in the absence of antigen-presenting cells (APC). The molecule recognized by this mAb, 9D3, was found to be expressed on almost all mature T cells and to be a protein of approximately 24 kD molecular mass. By expression cloning, this molecule was identified as CD9, 9D3 (anti-CD9) synergized with suboptimal doses of anti-CD3 mAb in inducing proliferation by virgin T cells. Costimulation was induced by independent ligation of CD3 and CD9, suggesting that colocalization of these two molecules is not required for T cell activation. The costimulation by anti-CD9 was as potent as that by anti-CD28. Moreover, anti-CD9 costimulated in a CD28-independent way because anti-CD9 equally costimulated T cells from the CD28-deficient as well as wild-type mice. Thus, these results indicate that CD9 serves as a molecule on T cells that can deliver a potent CD28-independent costimulatory signal.

scholarly journals Diacylglycerol kinase ζ limits IL-2-dependent control of PD-1 expression in tumor-infiltrating T lymphocytes

2020 ◽  
Vol 8 (2) ◽  
pp. e001521
Author(s):  
Javier Arranz-Nicolás ◽  
Miguel Martin-Salgado ◽  
Cristina Rodríguez-Rodríguez ◽  
Rosa Liébana ◽  
Maria C Moreno-Ortiz ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Therapeutic Potential ◽  
Interleukin 2 ◽  
Tumor Rejection ◽  
Cytotoxic T Cell ◽  
Adenocarcinoma Cells ◽  
The Impact

BackgroundThe inhibitory functions triggered by the programmed cell death-1 (PD-1) receptor following binding to its ligand (PD-L1) protect healthy organs from cytotoxic T cells, and neutralize antitumor T cell attack. Antibody-based therapies to block PD-1/PD-L1 interaction have yielded notable results, but most patients eventually develop resistance. This failure is attributed to CD8+ T cells achieving hyporesponsive states from which recovery is hardly feasible. Dysfunctional T cell phenotypes are favored by a sustained imbalance in the diacylglycerol (DAG)- and Ca2+-regulated transcriptional programs. In mice, DAG kinase ζ (DGKζ) facilitates DAG consumption, limiting T cell activation and cytotoxic T cell responses. DGKζ deficiency facilitates tumor rejection in mice without apparent adverse autoimmune effects. Despite its therapeutic potential, little is known about DGKζ function in human T cells, and no known inhibitors target this isoform.MethodsWe used a human triple parameter reporter cell line to examine the consequences of DGKζ depletion on the transcriptional restriction imposed by PD-1 ligation. We studied the effect of DGKζ deficiency on PD-1 expression dynamics, as well as the impact of DGKζ absence on the in vivo growth of MC38 adenocarcinoma cells.ResultsWe demonstrate that DGKζ depletion enhances DAG-regulated transcriptional programs, promoting interleukin-2 production and partially counteracting PD-1 inhibitory functions. DGKζ loss results in limited PD-1 expression and enhanced expansion of cytotoxic CD8+ T cell populations. This is observed even in immunosuppressive milieus, and correlates with the reduced ability of MC38 adenocarcinoma cells to form tumors in DGKζ-deficient mice.ConclusionsOur results, which define a role for DGKζ in the control of PD-1 expression, confirm DGKζ potential as a therapeutic target as well as a biomarker of CD8+ T cell dysfunctional states.

scholarly journals Allergen-Induced C5a/C5aR1 Axis Activation in Pulmonary CD11b+ cDCs Promotes Pulmonary Tolerance through Downregulation of CD40

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 300 ◽  
Author(s):  
Konstantina Antoniou ◽  
Fanny Ender ◽  
Tillman Vollbrandt ◽  
Yves Laumonnier ◽  
Franziska Rathmann ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
T Cell Proliferation ◽  
C5a Receptor ◽  
The Impact

Activation of the C5/C5a/C5a receptor 1 (C5aR1) axis during allergen sensitization protects from maladaptive T cell activation. To explore the underlying regulatory mechanisms, we analyzed the impact of C5aR1 activation on pulmonary CD11b+ conventional dendritic cells (cDCs) in the context of house-dust-mite (HDM) exposure. BALB/c mice were intratracheally immunized with an HDM/ovalbumin (OVA) mixture. After 24 h, we detected two CD11b+ cDC populations that could be distinguished on the basis of C5aR1 expression. C5aR1− but not C5aR1+ cDCs strongly induced T cell proliferation of OVA-reactive transgenic CD4+ T cells after re-exposure to antigen in vitro. C5aR1− cDCs expressed higher levels of MHC-II and CD40 than their C5aR1+ counterparts, which correlated directly with a higher frequency of interactions with cognate CD4+ T cells. Priming of OVA-specific T cells by C5aR1+ cDCs could be markedly increased by in vitro blockade of C5aR1 and this was associated with increased CD40 expression. Simultaneous blockade of C5aR1 and CD40L on C5aR1+ cDCs decreased T cell proliferation. Finally, pulsing with OVA-induced C5 production and its cleavage into C5a by both populations of CD11b+ cDCs. Thus, we propose a model in which allergen-induced autocrine C5a generation and subsequent C5aR1 activation in pulmonary CD11b+ cDCs promotes tolerance towards aeroallergens through downregulation of CD40.

Impact of Lenalidomide Maintenance Therapy on Immune Polarization and Activation in Multiple Myeloma

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2966-2966 ◽  
Author(s):  
Manisha Bhutani ◽  
David Foureau ◽  
Tammy Cogdill ◽  
Kyle Madden ◽  
Qing Zhang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Maintenance Therapy ◽  
T Cell Activation ◽  
Research Funding ◽  
Cell Activation ◽  
Lymphoid Cells ◽  
Relative Distribution ◽  
The Impact

Abstract BACKGROUND: Lenalidomide is an immunomodulatory drug (IMiD) with co-stimulatory effects on immune effector cells in vitro and is an approved treatment for multiple myeloma (MM), although its mode of action in patients is not well defined. We studied the impact of lenalidomide maintenance therapy, following autologous stem cell transplant (ASCT), on NK and NK-T polarization (i.e. activating or inhibitory molecules) and, T cell activation (early vs. late activation) in patients with multiple myeloma. PATIENTS AND METHODS: In this ongoing prospective study with a targeted enrollment of 28 newly diagnosed multiple myeloma patients, blood samples are being collected at 2 to 3 months post ASCT, before starting lenalidomide maintenance therapy (baseline), and serially after 1, 3 and 6 months of treatment (T+1mo, T+3mo, T+6mo). Using a 9 color flow cytometry panel, peripheral blood samples were analyzed for expression of CD3 and CD56 to define NK (CD56+ CD3-), NKT (CD56+ CD3+), and T cell (CD56- CD3+) subsets. Killer 'inhibitory' Ig-like receptors, (KiR2DS4, KiR3DL1) natural killer group 2 proteins (NKG2a, NKG2D) and natural killer p46 protein (NKp46) expression were quantified to assess polarization of NK, and NK-T cells. Programmed death receptor 1 (PD-1) and T-cell Ig and mucin receptor 3 (Tim3) expression was quantified to assess T cell activation state. Flow cytometry data were acquired on a BD FACSAria II, and analyzed using FlowJo version X software. RESULTS: Samples from 11 patients have been collected and analyzed so far (11 baseline, 6 T+1mo, 4 T+3mo). At baseline lymphoid cells represent 12-46% of white blood cells (WBC), this heterogeneity being mainly driven by a wide range of T cell relative distribution among patients (30-74 % lymphoid cells). Phenotypically, NK cells at baseline mainly express natural cytotoxicity receptors (NKp46 and NKG2D), whereas NK-T cell also express NKG2D but approximately 1/3 also express PD-1 indicating they may be functionally defective. T cells at baseline express early T cell activation markers NKG2D and approximately 1/3 also stained positive for late T cell activation marker PD-1. Lymphoid cells relative distribution among WBC tends to normalize at T+1mo of treatment (15 to 35 % of WBC) before expanding at T+3mo (35 to 43 % of WBC). Phenotypically, across the 27 immune variables analyzed, each multiple myeloma patient displayed high level of immune homeostasis after 1 or 3 months of lenalidomide treatment. Noticeably, Nkp46 expression by NK cell and PD-1 expression by NK-T cells decreased in 4/6 patients and, NKG2D expression by T cell decreased in all but one patient during lenalidomide therapy. CONCLUSION: To our knowledge, this is the first study examining the influence of lenalidomide maintenance on the comprehensive immune repertoire in the post-ASCT setting in MM patients. The wide heterogeneity of NK, NK-T and T cell distribution observed at baseline among lymphoid cells indicates the potential effect of post-ASCT immune reconstitution and immunomodulatory the impact of lenalidomide. The capacity of lenalidomide to mediate effects on several immune cells raises the question as to which, if any, of these changes correlate with clinical responses. In our study, serially collected data from each patient, when completed would determine the impact of lenalidomide immunomodulatory effect of therapeutic efficacy and PFS duration in relation to immune reconstitution stage. Disclosures Cogdill: Millennium: Speakers Bureau; Onyx: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Speakers Bureau. Ghosh:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Usmani:Sanofi: Honoraria, Research Funding; Millennium: Honoraria, Speakers Bureau; Onyx: Honoraria, Research Funding, Speakers Bureau; Pharmacyclics: Research Funding; Celgene: Honoraria, Speakers Bureau; Janssen Oncology: Honoraria, Research Funding; Array BioPharma: Honoraria, Research Funding.

Glycoprotein D, a checkpoint inhibitor of early T-cell activation, to improve immunogenicity and efficacy of an HPV-16 vaccine in preclinical studies.

2020 ◽  
Vol 38 (5_suppl) ◽  
pp. 71-71
Author(s):  
Hildegund Ertl ◽  
Zhiquan Xiang ◽  
Yan Li ◽  
Andrew Luber ◽  
Colin Magowan ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Tumor Antigens ◽  
Checkpoint Inhibitor ◽  
Wild Type ◽  
Hpv 16 ◽  
Cell Responses

71 Background: CD8+ T cells can inhibit tumor progression, but their induction is hampered by the low immunogenicity of most tumor antigens. HSV-1 glycoprotein D (gD), when genetically expressed as a fusion protein with tumor antigens, serves as a checkpoint inhibitor of the B and T cell attenuator (BTLA)-herpes virus entry mediator (HVEM) pathway, which acts early during T cell activation. HSV-1 gD thereby augments antigen-driven CD8+ T cell responses. We describe the immunogenicity and efficacy of a chimpanzee adenoviral vector (AdC) vaccine containing a detoxified E7/E6/E5(AdC-gDE765dt) sequence of HPV-16 fused into gD. Methods: The frequency of HPV-16 E7-specific CD8+ T-cells was assessed by tetramer staining in C57/Bl6 mice 14 days after a single IM vaccination with AdC vectors encoding wild-type or mutant HPV-16 oncoproteins expressed within gD, a non-HVEM-binding form of gD or without gD. Efficacy was tested in a TC-1 tumor cell challenge model with mice receiving no treatment or a single IM vaccine injection 3 days after tumor cell transplantation. Mice were followed for 80 days. Results: The addition of gD increases HPV-16 E7-specific CD8+ T-cell frequencies approximately 10-fold. T cell responses are similar to AdC vaccines expressing wild-type or mutant oncoproteins within gD. All AdC-gDE765dt treated mice show delayed tumor progression after a single vaccination with 50% of animals remaining tumor-free at study completion. Conclusions: These results show that the addition of gD, an early checkpoint inhibitor, which acts locally at the site of T cell stimulation, to an HPV-16 vaccine markedly improves the vaccine’s immunogenicity and efficacy. AdC-gDE765dt is currently in GMP manufacture for Phase 1 investigation in HPV-16 infected patients.

Suppressive activity of regulatory T cells correlates with high CD4+ T-cell counts and low T-cell activation during chronic simian immunodeficiency virus infection

AIDS ◽  
2011 ◽  
Vol 25 (5) ◽  
pp. 585-593 ◽  
Author(s):  
Ingrid Karlsson ◽  
Benoît Malleret ◽  
Patricia Brochard ◽  
Benoît Delache ◽  
Julien Calvo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Virus Infection ◽  
Regulatory T Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cd4 T Cell ◽  
Suppressive Activity ◽  
Cell Counts ◽  
Immunodeficiency Virus

Abstract P167: Title: Prediction of Arterial Stiffness from Early T-cell Activation among HIV and HCV Co-infected Women in the Women's Interagency HIV Study (WIHS)

Circulation ◽  
2012 ◽  
Vol 125 (suppl_10) ◽  
Author(s):  
Roksana Karim ◽  
Naoko Kono ◽  
Robert Kaplan ◽  
Wendy J Mack ◽  
Howard N Hodis ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Arterial Stiffness ◽  
Hiv Infection ◽  
T Cell Activation ◽  
Cell Activation ◽  
Infection Status ◽  
Activation Markers ◽  
Color Flow ◽  
The Impact

Introduction: Activation of T-lymphocytes, a hallmark of HIV infection, reaches a set point early in HIV infection and persists even after viral suppression with highly active antiretroviral therapy (HAART). Early T-cell activation predicts subsequent CD4 depletion, progression to AIDS and survival. HIV-infected subjects are at high risk for premature atherosclerosis. Little is known regarding the impact of early T cell activation on arterial stiffness. While Kaplan et al. (2011) were the first and only group to show a cross-sectional association, we investigate here if early T cell activation can predict future arterial stiffness. Hypothesis: High early T cell activation will predict increased arterial stiffness, measured 5.5 (IQR=2.5-7.5) years later, in HIV and HCV co-infected women. Methods: A longitudinal study nested within the WIHS, an ongoing prospective cohort study. Percentages of CD4 and CD8 T cell activation, assessed by CD38 and HLA-DR co-expression using 3-color flow cytometry, were measured on average 5.5 years before arterial stiffness assessments (carotid artery distensibility, and Young’s elastic modulus for elasticity) using B-mode carotid ultrasound. Multiple linear regression models evaluated the association between log-transformed T cell activation markers (independent variables) and arterial stiffness (dependent variable). Analyses were stratified by HCV co-infection status and by pre- and post-HAART assessment of T cell activation. Results: A total of 376 HIV+ women (185 HCV+) were included in the analysis. Participants were on average 46(SD=9) years old, 59% Black, and 49% were current smokers. Activation of both CD4 and CD8 T cells significantly univariately predicted reduced distensibility and elasticity among HIV-infected women. CD4 activation continued to significantly predict distensibility (β(SEM)= −3.51(1.30) 10 −6* N −1* m 2 , p=0.01), and elasticity (0.11(0.04)10 5* N * m 2 , p=0.004) with adjustment for age, race, BMI, smoking, ART, CD4 count, and HIV RNA. CD8 activation was no longer associated after adjustment. When stratified by HCV co-infection status, the prediction of arterial stiffness parameters from early CD4 activation was somewhat stronger among the HIV+/HCV+ women compared to HIV+/HCV- women (β(SEM)= −4.44(1.93), p=0.02 vs. −3.04(1.84), p=0.10 for distensibility, and 0.17(0.06), p=0.003 vs. 0.09(0.05), p=0.09 for elasticity); however the test for interaction was not statistically significant. In a subset of 188 women, CD4 activation measured both pre- and post-HAART significantly predicted later arterial stiffness. Conclusions: CD4 activation level predicts future arterial stiffness in HIV-infected women, perhaps more markedly among HCV co-infected women. These data confirm the proinflammatory impact of activated T cells that can cause vascular dysfunction and shed light on the early onset of atherogenesis.

The Acquired CD40L Deficiency in B-CLL Is Reversible and Due To Contact Dependant and Independent Factors.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2813-2813
Author(s):  
Andrea G.S. Buggins ◽  
Julie Richards ◽  
Piers E.M. Patten ◽  
Ghulam J. Mufti ◽  
Stephen Devereux
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Cell Contact ◽  
Normal Donor ◽  
The Impact

Abstract Interactions between CD40L (CD154) and its receptor CD40, are of central importance in T-cell mediated B-cell activation, proliferation and isotype switching and the regulation of antigen presentation by dendritic cells. Peripheral blood T lymphocytes from patients with B cell chronic lymphocytic leukemia (B-CLL) have an acquired defect of activation induced CD40L expression that might contribute to the immunodeficiency characteristic of the disease. In view of recent reports that T-cells within bone marrow and lymph node pseudofollicles express CD40L we have re-examined the mechanism of the deficiency in PB cells. Activation of normal resting naïve and memory (CD45RA+ and −) T-cells with PMA and ionomycin increased the number expressing surface CD40L from a mean of 2 and 0% to 81.2 and 66.5% respectively. In line with previous reports, up-regulation of CD40L by CD4+45RA+ and CD4+45RA− T-cells from patients with B-CLL was reduced to a mean of 11.8% and 2.6%. This defect is reversible since removal of T-cells from the malignant clone by CD3 selection increased the number of cells able to up-regulate CD40L to 62.2% and 61.8% for naïve and memory CD4 subsets. To investigate whether this phenomenon is due to cell contact or soluble mediators, washed leukemic cells or supernatant (SN) harvested from the same cell number were incubated with normal donor T-cells for 48 hours then stimulated for 4 hours with PMA and Ionomycin. B-CLL SN reduced CD40L up-regulation by a mean of 51% (range 14–86, n=17, p<0.0001) but co-culture reduced this further to a mean of 17% (range 7–33%, n=8, p<0.0001). Other markers of T-cell activation were similarly affected, for example T-cell IL-2 production was reduced to 40.1% ( 6.2% SEM, p < 0.0001) of the level seen in the absence of B-CLL SN. Although SN and cell contact both prevented CD40L up-regulation, only cell contact caused its down-regulation in pre-activated T-cells (reduced to 94% of normal with SN, [range 93–96%, n=3, p=0.5] and 14% of normal with co-culture [range 4.3–21.7%, n=6, p p<0.0001]). The acquired CD40L deficiency observed in patients with B-CLL is thus reversible and mediated by contact with leukemic cells and soluble mediator(s). B-CLL cells are known to secrete a number of factors that might produce this effect. Studies using blocking monoclonal antibodies and immuno-adsorption excluded the most likely candidates including TGF-beta, soluble CD40 and soluble IL-2R. These findings indicate that regulation of the CD40/CD40L system in B-CLL is more complex than previously reported however the impact of this on disease pathogenesis needs to be determined.

Fas- and Fas Ligand Rather Than Perforin-Mediated Apoptosis Has a Dominant Role in Target Cell Death in Murine Models of Immune- Mediated Bone Marrow Failure

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1039-1039
Author(s):  
Jichun Chen ◽  
Stephanie O. Omokaro ◽  
Annahita K. Sarcon ◽  
Neal Young
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Aplastic Anemia ◽  
T Cell Activation ◽  
Cell Activation ◽  
Fas Ligand ◽  
Wild Type ◽  
Cell Destruction ◽  
Immune Mediated

Abstract Fas-Fas ligand and perforin-granzyme are two important cell death pathways associated with cytotoxic T cell induced target cell apoptosis. In patients with immune-mediated aplastic anemia, the development of bone marrow (BM) failure is associated with up-regulation in Fas ligand expression on effector cytotoxic T cells and elevated Fas expression on target BM cells. In some aplastic anemia patients, peripheral blood T lymphocytes also carry polymorphisms in the perforin gene which have been associated with familial hemophagocytosis. These findings suggested that Fas ligand/Fas might be the key signaling molecules mediating cell destruction while perforin might also play a role in the development of BM failure in patients with aplastic anemia. We have modeled immune-mediated BM failure in the mouse by infusing allogeneic lymph node (LN) cells from C57BL/6 (B6) donors into sublethally-irradiated CByB6F1 and C.B10 recipients that are mismatched at either major histocompatibility (MHC) or minor histocompatibility (minor-H) loci. Expansion and activation of allogeneic T cells results in increased production of the inflammatory cytokines gamma interferon and tissue necrosis factor alpha in recipient BM, massive BM cell destruction, severe marrow hypoplasia, and fatal pancytopenia. In the current study, we directly tested the roles of Fas, Fas ligand and perforin in the development of BM failure by using murine models with spontaneous mutations at the lymphoproliferation (lpr) and generalized lymphoproliferative disease (gld) loci, or with germline deletion of the gene perforin (prf−/−). Fas and Fas ligand-deficient lpr and gld mutant mice had no evidence of hematopoietic deficiency despite their autoimmune environment and marked lymphoproliferation. LN cells from lpr and gld mice caused significantly less apoptosis to minor-H mismatched C.B10 BM cells when co-cultured in a cytotoxicity assay in vitro, in comparison to LN cells from wild-type B6 mice. Infusion of lpr, gld, and B6 donor LN cells into sub-lethally irradiated CB10 recipients all caused massive T cell expansion in recipient BM with high level expression of CD11a, indicative of T cell activation, but only B6 LN cells caused severe BM destruction. In contrast, recipients of lpr and gld LN cells had only mild to moderate pancytopenia and marrow hypocellularity. We inferred from these results that disruption of the Fas ligand/Fas signaling pathway effectively abrogated immune mediated marrow destruction. To test the role of perforin in BM failure, we first analyzed prf−/−- mice and found no obvious change in cellular composition in lymphohematopoietic tissues in comparison to wild-type B6 controls. LN cells from prf−/− mice showed reduced ability to induce C.B10 BM cell apoptosis in an in vitro cytotoxicity assay when compared to wild-type B6 LN cells. Infusion of 5–10 million prf−/− LN cells into CByB6F1 and C.B10 recipients produced obvious BM failure in both recipient types with pancytopenia and marrow hypoplasia about 80–90% as severe as in control recipients of 5 million B6 LN cells. In both CByB6F1 and C.B10 recipients, infused prf−/− LN cells resulted in less T cell expansion, a similar level of T cell activation, higher proportions of T cells containing gamma-interferon and tissue necrosis factor-alpha, and a higher proportion of T cells expressing the Fas ligand CD178, in comparison to the infused B6 LN cells. We conclude that Fas-Fas ligand-mediated transmembrane signaling provides the major cell death pathway, while perforin-granzyme-mediated exocytosis plays a minor role, in BM cell destruction in animal models of immune-mediated BM failure.

Immunosuppressive Drugs up-Regulate the Immunoinhibitory Receptor Osteoactivin On Human Monocyte-Derived Dendritic Cells

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3284-3284
Author(s):  
Sabine Braun ◽  
Michael Gutknecht ◽  
Mark-Alexander Schwarzbich ◽  
Lothar Kanz ◽  
Helmut R Salih ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cyclosporine A ◽  
Cell Activation ◽  
Immunosuppressive Drugs ◽  
Type I ◽  
Transmembrane Glycoprotein ◽  
The Impact

Abstract Abstract 3284 Introduction: Dendritic cells (DC) abundantly express the type I transmembrane glycoprotein Osteoactivin (OA) - also known as transmembrane glycoprotein NMB and DC-HIL - compared to low expression levels on monocytes. Antigen-presenting cells interact via OA with the type I transmembrane proteoglycan syndecan-4 (SD-4) on T cells which inhibits T cell activation. We previously reported on increased expression of OA upon exposure of monocyte-derived DC (moDC) to immunosuppressive drugs (e.g., Gutknecht et al ASH annual meeting 2011). Here we extended these analyses and comparatively analyzed the impact of various immunsuppressive drugs (ID) on moDC phenotype and function. Methods: The moDC were generated from blood monocytes by plastic adherence and exposure to GM-CSF and IL-4. Clinically relevant concentrations of ID were added to the culture medium every second day starting with the first day of culture (cyclosporine A: 1μg/ml, prednisolone: 3.5μg/ml, tacrolimus: 10ng/ml, mycophenolat-mofetil 0.1μM, methotrexat 230ng/ml). Cells were harvested for immunophenotyping by flow cytometry, western-blotting and real-time PCR. Cytokine release by moDC was determined on day 7 by ELISA. Functional properties were determined by mixed lymphocyte reactions (MLR) on day 7 of culture. Results: Exposure of moDC to therapeutic concentrations of prednisolone resulted in significantly reduced expression of the costimulatory molecules CD83 and CD86 and increased levels of the monocyte marker CD14, indicative of impaired differentiation. Tacrolimus significantly increased CD14 expression and reduced CD83 expression, while the other ID did not cause significant alterations. All ID altered the release of the immunomodulatory cytokines IL-10, IL-6 and TGF-ß. Notably, all ID except cyclosporine A caused a substantial upregulation of the immunoinhibitory receptor OA in moDC. The extent of OA expression increased over time of exposure to ID during differentiation and resulted in reduced capacity of the moDC to stimulate allogenic T cells which could be restored by disruption of OA/SD-4 interaction using a blocking OA antibody. Conclusion: Increased expression of OA on moDC upon exposure to ID contributes to inhibition of T-cell activation. The mechanisms underlying the differential effect of cyclosporine A are presently under study. Our results indicate that targeting OA/SD-4 interaction may hold promise for modulation of T cell responses in various pathophysiological conditions and immunotherapeutic strategies. Disclosures: No relevant conflicts of interest to declare.

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