Abstract 44: Failure of Protective Autoimmunity in Mouse and Human Atherosclerosis

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Dennis Wolf ◽  
Teresa Gerhardt ◽  
Nathaly Anto Michel ◽  
Bjarke Hansen ◽  
Alessandro Sette ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Nodes ◽  
Mhc Class Ii ◽  
T Regulatory Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
T Cell Response ◽  
Regulatory Cells ◽  
Protective Autoimmunity

Background: In atherosclerosis, CD4 + T helper cells recognize auto-antigens including ApoB, the main protein in low-density lipoprotein (LDL). However, atherosclerosis-specific, auto-reactive CD4 + T cells have not been detected in vivo , and their function is unknown. Methods and Results: We have previously identified peptides derived from mouse ApoB that bind with high affinity to the MHC class II molecule of C57BL/6 mice (I-A b ). We designed and validated a new multimer of a recombinant MHC-II molecule fused to one ApoB auto-epitopes, P6 (TGAYSNASSTESASY, P6:I-A b ), that enabled detection of low-affinity, P6-reactive CD4 + T cells. Using this P6:I-A b multimer, we identified ApoB-reactive CD4 + T cells in healthy, young C57BL/6 mice that were predominately differentiated T-regulatory cells (T regs ) and expressed IL-10, a known atheroprotective cytokine. This population was detectable in lymph nodes and already showed a memory phenotype in young animals without atherosclerosis. In Apoe -/- mice, adoptively transferred ApoB P6-specific T regs accumulated in the aorta and draining lymph nodes and gave rise to pathogenic T H 1 and T H 17 cells. This phenotypic switch was caused by enhanced plasticity of antigen-specific T regs as evidenced by multiple clusters of intermediate T reg -T eff phenotypes in single cell RNA sequencing of 4485 antigen-specific CD4 + T cells. In the plaque, many T cells were ex-T regs as identified by a FoxP3 lineage tracker mouse, suggesting that atherosclerosis-specific CD4 + T cells lost their regulatory capacity. Vaccination with P6 maintained a protective phenotype in antigen-specific T regs and protected from atherosclerosis. In humans, ApoB-specific CD4 + T cells from atherosclerotic patients showed the same cytokine patterns found in mouse CD4 + T cells, suggesting that autoimmunity to ApoB is protective first, but later gives rise to a pathogenic CD4 + T cell response that aggravates atherosclerosis. Conclusion: Protective T-regulatory cells recognizing peptide antigens of ApoB exist in naïve mice, protect against atherosclerosis, but convert into pathogenic T H 1 and -17 cells during the natural course of disease in mice and humans. These results call for immunomodulatory therapies to maintain protective autoimmunity.

Abstract 21: A Natural Repertoire of T Cells Recognizing ApoB-100 is Generated Early in Life and is Progressively Depleted During Atherosclerotic Disease

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Dennis Wolf ◽  
Teresa Gerhardt ◽  
Jacqueline Miller ◽  
Sara McArdle ◽  
Takayuki Kimura ◽  
...  
Keyword(s):  
T Cells ◽  
Lymph Nodes ◽  
Mhc Class Ii ◽  
T Regulatory Cells ◽  
Low Density Lipoprotein ◽  
Large Body ◽  
Density Lipoprotein ◽  
Western Diet ◽  
Chow Diet ◽  
Progressive Loss

Background: A large body of evidence implicates a role for T cell driven auto-immunity in atherosclerosis. T cells in the atherosclerotic plaque specifically respond to auto-antigens, including ApoB-100, the main protein in low-density lipoprotein (LDL). However, existence, function, and location of auto-reactive T cells in mice have not been demonstrated. Methods and Results: We have previously identified several peptides derived from mouse ApoB-100 that bind with high affinity to the I-A b MHC class II molecule of C57BL/6 mice. Immunization with these peptides conferred atheroprotection. We designed a novel fluorochrome-labeled P6:I-A b multimer to detect T cells specifically recognizing this complex by flow cytometry. Surprisingly, we detected small numbers of P6:I-A b+ CD4 + T cells in young C57Bl/6 mice that reside in peripheral lymph nodes, indicating the existence of a small natural repertoire of P6:I-A b auto-reactive T cells. This repertoire of T cells was increased in atherosclerosis-prone A poe -/- and Ldlr -/- mice and showed signs of previous antigen-exposure in 4 week old animals. T cells recognizing P6:I-A b were undetectable directly after birth, but expanded rapidly within the first 28 days in lymph nodes. The majority of P6:I-A b+ T cells expressed the defining transcription factors of T H 1, T-bet, T H 17, ROR-gamma T, or of T-regulatory cells, FoxP3. Feeding of Apoe -/- mice with a western diet induced a further skew towards the T H 1 and T H 17 lineage, but also resulted in a progressive loss of antigen-specific cells over time. In Apoe -/- mice fed with a western diet for 1 year, but not in Apoe -/- mice fed with a standard chow diet, auto-reactive T cells disappeared. Mechanistically, we found enhanced expression of exhaustion markers like ICOS-1 or PD-1 in antigen-specific T cells likely due to persisting antigen-exposure in this model. Conclusion: Our findings indicate that T cells specifically recognizing a peptide derived from ApoB-100 do not expand during the natural course of disease, but instead exist in atherosclerosis-prone animals in early life. Chronic exposure to antigen induces a progressive loss of auto-reactive T cells.

CD4+CD25+ T Cells Can Inhibit CD8 T Cell Mediated GVHD: Requirement for In Vivo Recognition of Allogeneic Host MHC Class II Antigens.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1307-1307
Author(s):  
Robert B. Levy ◽  
Angela Jones
Keyword(s):  
Weight Loss ◽  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd8 T Cells ◽  
T Regulatory Cells ◽  
Cd8 T Cell ◽  
Class Ii ◽  
Regulatory Cells

Abstract CD4 regulatory T (Treg) cells have shown promise in the transplantation mileu including the ability to inhibit the development of graft vs host disease (GVHD) following allogeneic hematopoietic stem cell transplants (HCT). The antigen specificity of the Treg population(s) involved is not yet clear nor is the role of their activation following transplant. We are interested in determining the requirement for recognition of host MHC antigens following infusion of CD4+CD25+ T cells in an experimental model of GVHD. To clearly distinguish the requirements of regulatory vs GVH reactive cells, a model of CD8 T cell mediated GVHD was developed using highly purified BALB/c (H2d) donor CD8+ T cells (Miltenyi column, 95-98%). CD8 T cells were transplanted together with T cell depleted (TCD) BALB/c BMC into 12.0 GY (6.0 Gy split dose) TBI conditioned C57BL/6 (B6, H2b) recipients. To support development of GVHD by these cells, resistance was inhibited by treatment of recipients with anti-NK1.1mab (PK136) at Days -1, 0 and +7. BALB/c CD8+ T cells at doses of 5.0x106 but not 2.5x106 induced weight loss and some lethality in B6 recipients. 5x106 CD8+ T cells were then transplanted into B6-MHC class II−/ − recipients. GVHD symptoms including weight loss and lethality were readily apparent in these mice post-transplant. Interestingly, GVHD was consistently more severe with respect to the induction of weight loss and lethality in MHC Class II−/ − vs B6-wt recipients. Highly enriched BALB/c CD4+CD25+ T cells (> 95%) were produced from spleen and lymph node cells following negative (B-cells, CD8 and NK) and positive (CD25) selection using Miltenyi magnetic bead columns. Co-transplant of 1x106 CD4+CD25+ T cells together with BALB/c CD8+ T cells into B6 recipients inhibited GVHD as assessed by the absence of weight loss and lethality compared to B6 recipients of CD8+ T cells alone. In contrast, BALB/c CD4+CD25+ T cells failed to protect B6-MHC class II−/ − recipients from severe CD8+ T cell mediated GVHD. These findings demonstrate that donor CD4+ T regulatory cells can suppress GVHD inducing CD8+ T cells after the former recognize host class II alloantigen following transplant. We hypothesize that activated CD4+CD25+ T regulatory cells inhibit GVH reactive T cells at the host APC interface. Future studies in this model can be designed to examine ex-vivo activated and expanded CD4+CD25+ T regulatory populations. Transplant of such cells will enable us to address questions regarding the importance of in vivo recognition of host class II in the regulation of GVHD by these cells.

scholarly journals Inhibition of T cell response to native low-density lipoprotein reduces atherosclerosis

2010 ◽  
Vol 207 (5) ◽  
pp. 1081-1093 ◽  
Author(s):  
Andreas Hermansson ◽  
Daniel F.J. Ketelhuth ◽  
Daniela Strodthoff ◽  
Marion Wurm ◽  
Emil M. Hansson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
T Cell Responses ◽  
Class Ii ◽  
Low Density ◽  
Cell Responses ◽  
Ldl Particles

Immune responses to oxidized low-density lipoprotein (oxLDL) are proposed to be important in atherosclerosis. To identify the mechanisms of recognition that govern T cell responses to LDL particles, we generated T cell hybridomas from human ApoB100 transgenic (huB100tg) mice that were immunized with human oxLDL. Surprisingly, none of the hybridomas responded to oxidized LDL, only to native LDL and the purified LDL apolipoprotein ApoB100. However, sera from immunized mice contained IgG antibodies to oxLDL, suggesting that T cell responses to native ApoB100 help B cells making antibodies to oxLDL. ApoB100 responding CD4+ T cell hybridomas were MHC class II–restricted and expressed a single T cell receptor (TCR) variable (V) β chain, TRBV31, with different Vα chains. Immunization of huB100tgxLdlr−/− mice with a TRBV31-derived peptide induced anti-TRBV31 antibodies that blocked T cell recognition of ApoB100. This treatment significantly reduced atherosclerosis by 65%, with a concomitant reduction of macrophage infiltration and MHC class II expression in lesions. In conclusion, CD4+ T cells recognize epitopes on native ApoB100 protein, this response is associated with a limited set of clonotypic TCRs, and blocking TCR-dependent antigen recognition by these T cells protects against atherosclerosis.

CD4+CD25+Foxp3+ T Regulatory Cells Protect Against Murine Antibody-Mediated Transfusion-Related Acute Lung Injury (TRALI)

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2342-2342
Author(s):  
Rick Kapur ◽  
Michael Kim ◽  
Shanjee Shanmugabhavananthan ◽  
Edwin R. Speck ◽  
Rukhsana Aslam ◽  
...  
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
T Regulatory Cells ◽  
Blood Product ◽  
Lung Damage ◽  
Chronic Alcohol ◽  
Regulatory Cells ◽  
Chronic Alcohol Abuse ◽  
Murine Antibody

Abstract Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related fatalities and is characterized by acute respiratory distress following transfusion of blood products. Frequently, donor antibodies present in the transfused blood product are involved, such as anti-human leukocyte antigen (HLA) antibodies or anti-human neutrophil antigen (HNA) antibodies. Several animal models of TRALI have contributed to understanding the pathogenesis which, however, is still incompletely understood. Several cell types have also been suggested to be involved in antibody-mediated TRALI, including neutrophils, endothelial cells and monocytes. Most of the animal models are based on a two-hit paradigm, where the first hit is based on "patient predisposition", such as sepsis or chronic alcohol abuse, while the second hit is delivered in the form of "transfusion factors", such as antibodies present in the transfused blood product. Although most studies have focused on factors contributing to the development of antibody-mediated TRALI, the factors and mechanisms in place to protect against antibody-mediated TRALI have been underexplored. Adoptive transfer of lymphocytes into recipient severe combined immunodeficient (SCID) mice, in which the well-established TRALI inducing anti-MHC class I antibody clone 34-1-2s was injected, was previously shown to rescue TRALI induction by 34-1-2s. Here we describe, using a murine BALB/c antibody-mediated TRALI model based on injection of 34-1-2s, that CD4 T cells, and more specifically, CD4+CD25+Foxp3+ T regulatory cells (Tregs), are responsible for protection against murine antibody-mediated TRALI. Specific in vivo depletion of CD4+ T cells, or targeted in vivo depletion of Tregs, resulted in severe lung damage after 34-1-2s infusion, as determined by increased lung wet-to-dry ratios (a measure for pulmonary edema), generally greater than 5, indicative of severe pulmonary edema. This was accompanied by significant hypothermia, increased values of the neutrophil chemoattractant macrophage inflammatory protein 2 (MIP-2: equivalent of human IL-8), and increased pulmonary neutrophil accumulation, all compared to control groups. In contrast, systematic in vivo depletion of CD8+ T cells, B cells or monocytes, did not result in significant lung damage. Co-depletion of CD4+ T cells together with monocytes rescued the TRALI induction by 34-1-2s, validating the pathogenic role of monocytes in murine antibody-mediated TRALI induction. Based on MIP-2 values and in vitro studies, we suggest that Tregs suppress monocytes in order to prevent antibody-mediated TRALI. Overall, a novel first hit in TRALI induction could be identified in conditions that cause a decrease in Treg number or function, which could also explain the increased risk for human TRALI in cases of chronic alcohol abuse. In addition, therapies aimed at restoring Treg numbers or function may prove to be a novel therapeutic approach in antibody-mediated TRALI. Disclosures No relevant conflicts of interest to declare.

scholarly journals Expression of a MHC class II transgene determines both superantigenicity and susceptibility to mammary tumor virus infection.

1993 ◽  
Vol 178 (4) ◽  
pp. 1441-1445 ◽  
Author(s):  
C Pucillo ◽  
R Cepeda ◽  
R J Hodes
Keyword(s):  
T Cells ◽  
T Cell ◽  
Virus Infection ◽  
Mhc Class Ii ◽  
Mammary Tumor ◽  
Class Ii ◽  
T Cell Response ◽  
Mammary Tumor Virus ◽  
Tumor Virus

Milk-borne mouse mammary tumor virus (MMTV) is a type B retrovirus that induces mammary carcinoma. Infectious MMTV, as well as genomically integrated mouse mammary proviruses, encode superantigens that are recognized by T cells that express appropriate T cell receptor V beta products. To determine the relationship between the superantigenic property of milk-borne MMTV and its in vivo infectivity, mice which were either positive or negative for expression of a transgene-encoded E alpha E beta class II major histocompatibility complex (MHC) product were exposed to milk borne C3H MMTV. Superantigen-mediated deletion of V beta 14-expressing T cells occurred only in E alpha transgene-positive mice, indicating that the deletion was E alpha E beta dependent. When mice were analyzed for viral infection by assaying viral p28 in the milk of recipient females, significant p28 levels were found only in E alpha E beta transgene-positive mice. Similarly, the presence of C3H MMTV LTR mRNA in mammary glands, as detected by PCR, paralleled p28 levels. These findings indicate that E alpha expression or the E alpha-dependent T cell response to viral superantigen is causally related to susceptibility to MMTV infection, and that lack of a permissive class II product can protect mice from virus infection.

CCR6 selectively promotes monocyte mediated inflammation and atherogenesis in mice

2013 ◽  
Vol 110 (12) ◽  
pp. 1267-1277 ◽  
Author(s):  
Ela Karshovska ◽  
Jaroslav Pelisek ◽  
Miriam Koch ◽  
Sweena M. Chaudhari ◽  
Martin Busch ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Leukocyte Adhesion ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Aortic Sinus ◽  
Immune Priming ◽  
Atherosclerotic Burden

SummaryThe chemokine receptor CCR6 is expressed by various cell subsets implicated in atherogenesis, such as monocytes, Th17 and regulatory T cells. In order to further define the role of CCR6 in atherosclerosis, CCR6-deficient (Ccr6 -/-) mice were crossed with low-density lipoprotein receptor-deficient (Ldlr -/-) mice to generate atherosclerosis-prone mice deficient in CCR6. Compared to Ldlr -/- controls, atherosclerotic burden in the aortic sinus and aorta were reduced in Ccr6 -/- Ldlr -/- mice fed a high fat diet, associated with a profound depression in lesional macrophage accumulation. Local and systemic distributions of T cells, including frequencies of Th1, Th17 and regulatory T cells were unaltered. In contrast, circulating counts of both Gr-1high and Gr1low monocytes were reduced in Ccr6 -/- Ldlr -/- mice. Moreover, CCR6 was revealed to promote monocyte adhesion to inflamed endothelium in vitro and leukocyte adhesion to carotid arteries in vivo. Finally, CCR6 selectively recruited monocytes but not T cells in an acute inflammatory air pouch model. We here show that CCR6 functions on multiple levels and regulates the mobilisation, adhesion and recruitment of monocytes/macrophages to the inflamed vessel, thereby promoting atherosclerosis, but is dispensable for hypercholesterolaemia-associated adaptive immune priming. Targeting CCR6 or its ligand CCL20 may therefore be a promising therapeutic strategy to alleviate atherosclerosis.Note: The review process for this manuscript was fully handled by G. Y. H. Lip, Editor in Chief.

scholarly journals Interleukin-5 (IL-5) Therapy Prevents Allograft Rejection by Promoting CD4+CD25+ Ts2 Regulatory Cells That Are Antigen-Specific and Express IL-5 Receptor

2021 ◽  
Vol 12 ◽  
Author(s):  
Bruce M. Hall ◽  
Rachael M. Hall ◽  
Giang T. Tran ◽  
Catherine M. Robinson ◽  
Paul L. Wilcox ◽  
...  
Keyword(s):  
T Cells ◽  
T Regulatory Cells ◽  
Mixed Lymphocyte Culture ◽  
Lymphocyte Culture ◽  
Third Party ◽  
Regulatory Cells ◽  
Allograft Survival ◽  
Interleukin 5 ◽  
F344 Rats

CD4+CD25+Foxp3+T cell population is heterogenous and contains three major sub-groups. First, thymus derived T regulatory cells (tTreg) that are naïve/resting. Second, activated/memory Treg that are produced by activation of tTreg by antigen and cytokines. Third, effector lineage CD4+CD25+T cells generated from CD4+CD25- T cells’ activation by antigen to transiently express CD25 and Foxp3. We have shown that freshly isolated CD4+CD25+T cells are activated by specific alloantigen and IL-4, not IL-2, to Ts2 cells that express the IL-5 receptor alpha. Ts2 cells are more potent than naïve/resting tTreg in suppressing specific alloimmunity. Here, we showed rIL-5 promoted further activation of Ts2 cells to Th2-like Treg, that expressed foxp3, irf4, gata3 and il5. In vivo, we studied the effects of rIL-5 treatment on Lewis heart allograft survival in F344 rats. Host CD4+CD25+T cells were assessed by FACS, in mixed lymphocyte culture and by RT-PCR to examine mRNA of Ts2 or Th2-like Treg markers. rIL-5 treatment given 7 days after transplantation reduced the severity of rejection and all grafts survived ≥60d whereas sham treated rats fully rejected by day 31 (p<0.01). Treatment with anti-CD25 or anti-IL-4 monoclonal antibody abolished the benefits of treatment with rIL-5 and accelerated rejection. After 10d treatment with rIL-5, hosts’ CD4+CD25+ cells expressed more Il5ra and responded to specific donor Lewis but not self. Enriched CD4+CD25+ cells from rIL-5 treated rats with allografts surviving >60 days proliferated to specific donor only when rIL-5 was present and did not proliferate to self or third party. These cells had more mRNA for molecules expressed by Th2-like Treg including Irf4, gata3 and Il5. These findings were consistent with IL-5 treatment preventing rejection by activation of Ts2 cells and Th2-like Treg.

Azacitidine Induces Expansion of Regulatory T Cells and Tumour Specific CD8+ T Lymphocytes After Allogeneic Stem Cell Transplantation: A Strategy for Epigenetic Manipulation of a Graft-Versus-Leukemia Response

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 324-324 ◽  
Author(s):  
Mike Dennis ◽  
Oliver Goodyear ◽  
Justin Loke ◽  
Nadiria Jilani ◽  
Shamyla Siddique ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Response ◽  
T Regulatory Cells ◽  
Tumor Antigens ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Regulatory Cells ◽  
Post Transplant ◽  
Graft Versus Leukemia

Abstract Abstract 324 Disease relapse and graft-versus-host disease (GVHD) remain the commonest causes of treatment failure after allogeneic stem cell transplantation (SCT) for Acute Myeloid Leukemia (AML). Azacitidine (AZA) possesses inherent anti-leukemic activity but also expands immunomodulatory T regulatory cells in animal models and up-regulates the expression of tumor antigens in vitro. Reasoning that AZA might selectively augment a graft-versus-leukemia (GVL) without a concomitant increase in GVHD we have studied the tolerability and immunological sequelae of AZA administration in patients who have undergone a reduced intensity allogeneic SCT for AML. All patients were transplanted using a conditioning regimen consisting of fludarabine (30 mg/m2 IV × 5 days), melphalan (140 mg/m2IV), and alemtuzumab (10 mg IV × 5 days) with cyclosporine GVHD prophylaxis. Patients received AZA (36 mg/m2) × 5 days every 28 days commencing after sustained neutrophil and platelet engraftment at day +42 with the aim of administering monthly cycles of AZA until 12 months post-transplant. Numbers of CD4+CD25+CD127loFoxP3+ T regulatory cells were measured by flow cytometry. Tumor specific cytotoxic T lymphocytes (CTL) recognising members of the cancer testis antigen (CTA) family and WT1 were quantitated using a CD137 expression and enrichment assay. We report results on 27 patients (median age 59 years) who commenced treatment with AZA (follow-up 3–21 months). 11 patients were transplanted from an HLA identical related donor and 16 from a volunteer unrelated donor. Disease status at the time of transplant was: CR1 n=18; CR2 n=7; first relapse n=2. Post-transplant AZA was well tolerated and 24 patients tolerated at least three cycles of AZA. Haematological toxicity was modest with only two patients experiencing treatment delay for neutropenia, or thrombocytopenia. Three patients developed Grade 2 acute GVHD and no patient developed >Grade 2 acute GVHD. Two patients developed limited chronic GVHD. To date seven patients have relapsed at a median time of 6 months (4–15 months) post-transplant. Administration of AZA had no impact on absolute lymphocyte counts or CD8+ and CD4+ cell numbers compared with a control population of 17 patients transplanted using an identical conditioning regimen. However AZA administration was noted to increase the number of CD4+CD25+CD127loFoxP3+ regulatory T cells within the first 3 months post transplant compared with a time-matched control population (p=0.017) although there was no difference detectable at 6 or 12 months. AZA administration also induced a cytotoxic CD8+ T cell response to candidate tumor antigens MAGE, GAGE, RAGE and WT-1 in the peripheral blood. A CD8+ T cell response to these candidate tumor antigens was only detectable in 1/22 patients pre-transplant but circulating CTA- or WT1 specific CD8+ T cells were detected in 14/16 patients who had received at least six cycles of AZA with a frequency between 0.001–1.4% (mean 0.25%). In four patients with paired peripheral blood and bone marrow samples the size of the CD8+ T cell response was noted to be up to 100 fold greater in the bone marrow. Ex vivo characterisation of the CTA response using dextramers demonstrated the CD8+ T cell response to be effector memory (CD45RA-CCR7-) and functional assays confirmed by mobilization of CD107a and secretion of interferon-g, TNF-a and IL-2 in response to peptide. These data confirm the tolerability of adjunctive AZA post-transplant and its administration appears to be associated with a low incidence of both acute and chronic GVHD. The demonstration that AZA induces both early expansion of T regulatory cells and a tumor specific CD8+ CTL response highlight its potential use as a strategy to epigenetically manipulate a graft-versus-leukemia reaction after allogeneic SCT. Disclosures: Dennis: Celgene: Honoraria, Research Funding. Craddock:Celgene: Honoraria, Research Funding.

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