Macrophages Are the Key Players in Promoting Hyper-Inflammatory Response in a Mouse Model of TB-IRIS

TB-IRIS is an abnormal inflammatory response in a subset of HIV-TB co-infected patients shortly after initiation of anti-retroviral therapy (ART). Therapy in these patients could have greatly improved the life expectancy as ART reconstitutes the function and number of CD4+ T cells and many patients see improvement in symptoms but paradoxically up to 54% of co-infected patients develop TB-IRIS. Different studies have indicated that both innate and adaptive immunity are involved in the pathology of IRIS but the role of macrophages in abnormal activation of CD4+ T cells is poorly understood. Since macrophages are one of the major antigen-presenting cells and are infected by M.tb at a high frequency, they are very much likely to be involved in the development of TB-IRIS. In this study, we have developed a mouse model of experimental IRIS, in which M.tb-infected T-cell knockout mice undergo a fatal inflammatory disease after CD4+ T cell reconstitution. Lung macrophages and blood monocytes from M.tb-infected TCRβ−/− mice showed upregulated expression of cell surface activation markers and also showed higher mRNA expression of inflammation-associated chemokines and matrix metalloproteases responsible for tissue damage. Furthermore, cytokine and TLR signaling feedback mechanism to control excessive inflammation was also found to be dysregulated in these macrophages under lymphopenic conditions. Previous studies have shown that hyperactive CD4+ T cells are responsible for disease induction and our study shows that somehow macrophages are in a higher activated state when infected with M.tb in an immune-deficient condition, which results in excessive activation of the adoptively transferred CD4+ T cells. Understanding of the mechanisms underlying the pathophysiology of TB-IRIS would facilitate identification of prospective biomarkers for disease development in HIV-TB co-infected patients before starting antiretroviral therapy.

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CCL21 mediates CD4+ T-cell costimulation via a DOCK2/Rac-dependent pathway

Blood ◽

10.1182/blood-2009-01-200923 ◽

2009 ◽

Vol 114 (3) ◽

pp. 580-588 ◽

Cited By ~ 45

Author(s):

Kathrin Gollmer ◽

François Asperti-Boursin ◽

Yoshihiko Tanaka ◽

Klaus Okkenhaug ◽

Bart Vanhaesebroeck ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cd4 T Cells ◽

Cell Activation ◽

Early Time ◽

Cell Receptor ◽

Tcr Signaling ◽

Activation Markers

Abstract CD4+ T cells use the chemokine receptor CCR7 to home to and migrate within lymphoid tissue, where T-cell activation takes place. Using primary T-cell receptor (TCR)–transgenic (tg) CD4+ T cells, we explored the effect of CCR7 ligands, in particular CCL21, on T-cell activation. We found that the presence of CCL21 during early time points strongly increased in vitro T-cell proliferation after TCR stimulation, correlating with increased expression of early activation markers. CCL21 costimulation resulted in increased Ras- and Rac-GTP formation and enhanced phosphorylation of Akt, MEK, and ERK but not p38 or JNK. Kinase-dead PI3KδD910A/D910A or PI3Kγ-deficient TCR-tg CD4+ T cells showed similar responsiveness to CCL21 costimulation as control CD4+ T cells. Conversely, deficiency in the Rac guanine exchange factor DOCK2 significantly impaired CCL21-mediated costimulation in TCR-tg CD4+ T cells, concomitant with impaired Rac- but not Ras-GTP formation. Using lymph node slices for live monitoring of T-cell behavior and activation, we found that G protein-coupled receptor signaling was required for early CD69 expression but not for Ca2+ signaling. Our data suggest that the presence of CCL21 during early TCR signaling lowers the activation threshold through Ras- and Rac-dependent pathways leading to increased ERK phosphorylation.

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Long-term effects of intermittent interleukin 2 therapy in patients with HIV infection: characterization of a novel subset of CD4+/CD25+ T cells

Blood ◽

10.1182/blood.v100.6.2159.h81802002159_2159_2167 ◽

2002 ◽

Vol 100 (6) ◽

pp. 2159-2167 ◽

Cited By ~ 2

Author(s):

Irini Sereti ◽

Hector Martinez-Wilson ◽

Julia A. Metcalf ◽

Michael W. Baseler ◽

Claire W. Hallahan ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Lymphocytes ◽

Cd4 T Cells ◽

Interleukin 2 ◽

Hiv Patients ◽

Activation Markers ◽

Cd25 Expression ◽

Cell Counts

The long-term immunologic effects of intermittent interleukin 2 (IL-2) therapy were evaluated in a cross-sectional study by comparing 3 groups: HIV-seronegative volunteers, HIV-infected (HIV+) patients receiving highly active antiretroviral therapy (HAART), and HIV+ patients receiving HAART and intermittent IL-2. Whole-blood immunophenotyping was performed to study expression of the IL-2 receptor chains on T lymphocytes and natural killer cells and to further characterize CD4+/CD25+ T cells. Increased CD25 expression, especially in CD4+ T cells but also in CD8+ T cells, without increases in expression of the β and γ chains of the IL-2 receptor was detected in the IL-2 group. Up to 79% of naive CD4+ T cells (median, 61%) from patients in the IL-2 group expressed CD25, and the number of naive CD4+/CD25+ T cells correlated positively with both the total and naive CD4+ T-cell counts. A discrete population of CD45 double intermediate RA+/RO+CD4+ cells was also preferentially expanded in the IL-2 group, and the number of these cells strongly correlated with the total CD4+ count. Despite increases in CD25 expression, T lymphocytes from patients treated with IL-2 did not have increased expression of early (CD69) or late (CD95) activation markers or evidence of recent proliferation (Ki67). Both CD4+/CD25+ and CD4+/CD25− cells from IL-2–treated HIV+ patients proliferated in response to mitogens, specific antigens, and T-cell-receptor–mediated stimuli. Thus, intermittent administration of IL-2 in HIV+ patients leads to preferential expansion of a unique subset of CD4+ T cells that may represent a critical population in T-cell homeostasis.

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Induction and Break of Immune Tolerance to Human FVIII in a HLA-DRB1*1501 Humanized Hemophilic Mouse Model

Blood ◽

10.1182/blood.v118.21.2280.2280 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2280-2280

Author(s):

Katharina Nora Steinitz ◽

Brigitte Binder ◽

Christian Lubich ◽

Rafi Uddin Ahmad ◽

Markus Weiller ◽

...

Keyword(s):

T Cells ◽

Immune System ◽

T Cell ◽

Mouse Model ◽

Mhc Class Ii ◽

Immune Tolerance ◽

Cd4 T Cells ◽

Hemophilia A ◽

Class Ii ◽

T Cell Epitopes

Abstract Abstract 2280 Development of neutralizing antibodies against FVIII is the major complication in the treatment of patients with hemophilia A. Although several genetic and environmental risk factors have been identified, it remains unclear why some patients develop antibodies while others do not. Understanding the underlying mechanisms that drive the decision of the immune system whether or not to make antibodies against FVIII would help to design novel therapeutics. We used a new humanized hemophilic mouse model that expresses the human MHC-class II molecule HLA-DRB1*1501 on the background of a complete knock out of all murine MHC-class II genes. Initial studies had indicated that only a fraction of these mice developed antibodies when intravenously (i.v.) treated with human FVIII. These findings which resemble the situation in patients with severe hemophilia A, evoked the question if the lack of antibody development in non-responder mice reflects the induction of specific immune tolerance after i.v. application of FVIII or represent non-responsiveness for other reasons. We addressed this question by choosing another application route (subcutaneous, s.c.) and by combining i.v. application with a concomitant activation of the innate immune system applying LPS, a well characterized ligand for toll-like receptor 4, together with FVIII. Both strategies resulted in the development of antibodies in all mice included in the study what suggested that non-responsiveness against i.v. FVIII does not reflect an inability to develop antibodies against FVIII. Next, we asked if i.v. FVIII does induce immune tolerance in non-responder mice. We pretreated mice with i.v. FVIII, selected non-responder mice and challenged them with s.c. FVIII. None of the mice developed antibodies what indicated that i.v. pretreatment had induced immune tolerance in non-responder mice. Currently, we test the hypothesis that immune tolerance after i.v. application is induced and maintained by FVIII-specific regulatory T cells. The differences in responder rates after i.v. and s.c. application of FVIII raised the question if there are differences in FVIII T-cell epitopes involved in the initial activation of FVIII-specific CD4+ T cells. We obtained spleen cells from mice treated with either i.v. or s.c. FVIII and generated CD4+ T-cell hybridoma libraries that were tested for peptide specificities. For this purpose we used a FVIII peptide library containing 15 mers with an offset of 3 amino acids. Our results indicate that the pattern of FVIII-specific T-cell epitopes involved in the activation of FVIII-specific CD4+ T cells after i.v. and s.c. application of FVIII is almost identical and represents a small set of FVIII peptides distributed over the A1, A2, B, A3 and C1 domains. Based on our results we conclude that the new HLA-DRB1*1501 hemophilic mouse model represents an interesting opportunity to uncover the mechanisms that drive the decision of the immune system whether or not to develop antibodies against FVIII. Disclosures: Steinitz: Baxter BioScience: Employment. Binder:Baxter BioScience: Employment. Lubich:Baxter BioScience: Employment. Ahmad:Baxter BioScience: Employment. Weiller:Baxter BioScience: Employment. de la Rosa:Baxter BioScience: Employment. Schwarz:Baxter BioScience: Employment. Scheiflinger:Baxter BioScience: Employment. Reipert:Baxter Innovations GmbH: Employment.

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Differential Expression of Activation Markers by Mycobacterium tuberculosis-specific CD4+ T Cell Distinguishes Extrapulmonary From Pulmonary Tuberculosis and Latent Infection

Clinical Infectious Diseases ◽

10.1093/cid/ciz1070 ◽

2019 ◽

Vol 71 (8) ◽

pp. 1905-1911 ◽

Cited By ~ 8

Author(s):

Paulo S Silveira-Mattos ◽

Beatriz Barreto-Duarte ◽

Beatriz Vasconcelos ◽

Kiyoshi F Fukutani ◽

Caian L Vinhaes ◽

...

Keyword(s):

T Cells ◽

Mycobacterium Tuberculosis ◽

T Cell ◽

Hiv Infection ◽

Cd4 T Cells ◽

Cell Activation ◽

Cd4 T Cell ◽

Activation Markers ◽

Timely Initiation ◽

Latent Tb

Abstract Background Diagnosis of active tuberculosis (ATB) currently relies on detection of Mycobacterium tuberculosis (Mtb). Identifying patients with extrapulmonary TB (EPTB) remains challenging because microbiological confirmation is often not possible. Highly accurate blood-based tests could improve diagnosis of both EPTB and pulmonary TB (PTB) and timely initiation of anti-TB therapy. Methods A case-control study was performed using discriminant analyses to validate an approach using Mtb-specific CD4+T-cell activation markers in blood to discriminate PTB and EPTB from latent TB infection (LTBI) as well as EPTB from PTB in 270 Brazilian individuals. We further tested the effect of human immunodeficiency virus (HIV) coinfection on diagnostic performance. Frequencies of interferon-γ +CD4+T cells expressing CD38, HLADR, and/or Ki67 were assessed by flow cytometry. Results EPTB and PTB were associated with higher frequencies of CD4+T cells expressing CD38, HLADR, or Ki67 compared with LTBI (all P values < .001). Moreover, frequencies of HLADR+ (P = .03) or Ki67+ (P < .001) cells accurately distinguished EPTB from PTB. HIV infection did not affect the capacity of these markers to distinguish ATB from LTBI or EPTB from PTB. Conclusions Cell activation markers in Mtb-specific CD4+T cells distinguished ATB from LTBI and EPTB from PTB, regardless of HIV infection status. These parameters provide an attractive approach for developing blood-based diagnostic tests for both active and latent TB.

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Transient NKG2D Blockade Attenuates Graft-Versus-Host Disease While Preserving Graft-Versus-Leukemia Effects

Blood ◽

10.1182/blood.v122.21.3242.3242 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3242-3242 ◽

Cited By ~ 1

Author(s):

Mobin Karimi ◽

Theresa M Leichner ◽

Atsushi Satake ◽

David Raulet ◽

Taku Kambayashi

Keyword(s):

T Cells ◽

T Cell ◽

Mouse Model ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Cd8 T Cell ◽

Allogeneic Hsct ◽

Isotype Control ◽

Isotype Control Antibody

Abstract In allogeneic hematopoietic stem cell transplantation (HSCT), identification of mechanisms to control GVHD yet maintain GVL responses is of critical importance. One key effector cell that mediates both GVHD and GVL is the CD8+ T cell, which expands in response to T cell receptor (TCR) stimulation by allogeneic MHC class I molecules during allogeneic HSCT. In addition, co-stimulatory molecules facilitate the TCR-mediated activation process and the effector function of CD8+ T cells. Recent data suggest that NKG2D may play a co-stimulatory role in activation and in augmenting anti-tumor cytotoxic responses of CD8+ T cells. NKG2D is an NK cell-associated receptor that is also expressed on all human CD8+ T cells and on activated/memory mouse CD8+ T cells. NKG2D recognizes a diverse array of MHC-related ligands that are expressed by many tumors and induced on cells under stress such as myeloablative conditioning during HSCT. As the role of NKG2D in allogeneic HSCT is unknown, we hereby investigated the role of NKG2D on CD8+ T cells in a mouse model of GVHD and GVL. Our results show that a large fraction (40-50%) of mouse CD8+ T cells inducibly express NKG2D upon activation by allogeneic MHC in vitro and in vivo. To test the role of NKG2D in GVHD pathogenesis, we employed a major MHC-mismatched mouse model of GVHD involving the transplantation of C57BL/6-derived CD8+ T cells and bone marrow (BM) into lethally irradiated Balb/c mice (B6→Balb/c). Using 3 different approaches to block NKG2D on CD8+ T cells (shRNA-mediated silencing, germline NKG2D deficiency, and antibody blockade), we found that weight loss, clinical score, and survival were significantly improved in transplanted mice with NKG2D blockade. The attenuation in GVHD correlated with a significant reduction in TNFα and IFNγ production, cytotoxicity, and proliferation (BrdU incorporation) by CD8+ T cells. Although CD4+ T cells did not express NKG2D, a protective effect of NKG2D blockade was still observed in GVHD induced by a mixture of CD8+ and CD4+ T cells, albeit to a lesser extent. We next tested the effects of NKG2D on CD8+ T cell-mediated GVL. To this end, irradiated Balb/c mice were transplanted with C57BL/6-derived CD8+ T cells and BM, challenged intravenously with luciferase-positive A20 leukemia cells, and followed by total body imaging of luciferase-expressing cells. Given that NKG2D ligands are constitutively expressed on many tumor cells and plays an important role in their eradication, we predicted that continuous NKG2D blockade would inhibit GVL effects. However, as NKGD ligands are upregulated only transiently on stressed normal tissue, we reasoned that transient NKG2D blockade might be sufficient to attenuate GVHD and allow CD8+ T cells to regain their GVL function. To test this hypothesis, we compared the effect of anti-NKG2D antibody as continuous treatment or as 5-day transient treatment to mice receiving isotype control antibody. As expected, mice that received isotype control antibody cleared the A20 cells but developed severe GVHD. Continuous anti-NKG2D antibody-mediated blockade improved GVHD but also blunted the GVL response leading to increased A20 growth. In contrast, a large proportion of mice transiently treated with anti-NKG2D antibody cleared the A20 cells, while maintaining the attenuated GVHD state. Together, these data support a positive role of NKG2D on CD8+ T cells in mediating GVHD and GVL. Given the transient nature of NKG2D ligand upregulation on stressed tissues, a window of opportunity may exist where transient NKG2D blockade could provide a novel therapeutic strategy for treatment of acute GVHD while preserving the GVL function of CD8+ T cells after allogeneic HSCT. Disclosures: No relevant conflicts of interest to declare.

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Trans-Ned 19-Mediated Antagonism of Nicotinic Acid Adenine Nucleotide—Mediated Calcium Signaling Regulates Th17 Cell Plasticity in Mice

Cells ◽

10.3390/cells10113039 ◽

2021 ◽

Vol 10 (11) ◽

pp. 3039

Author(s):

Mikołaj Nawrocki ◽

Niels Lory ◽

Tanja Bedke ◽

Friederike Stumme ◽

Björn-Phillip Diercks ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Mouse Model ◽

Nicotinic Acid ◽

Cd4 T Cells ◽

Th17 Cells ◽

T Cell Differentiation ◽

Cd4 T Cell

Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most potent Ca2+ mobilizing agent and its inhibition proved to inhibit T-cell activation. However, the impact of the NAADP signaling on CD4+ T-cell differentiation and plasticity and on the inflammation in tissues other than the central nervous system remains unclear. In this study, we used an antagonist of NAADP signaling, trans-Ned 19, to study the role of NAADP in CD4+ T-cell differentiation and effector function. Partial blockade of NAADP signaling in naïve CD4+ T cells in vitro promoted the differentiation of Th17 cells. Interestingly, trans-Ned 19 also promoted the production of IL-10, co-expression of LAG-3 and CD49b and increased the suppressive capacity of Th17 cells. Moreover, using an IL-17A fate mapping mouse model, we showed that NAADP inhibition promotes conversion of Th17 cells into regulatory T cells in vitro and in vivo. In line with the results, we found that inhibiting NAADP ameliorates disease in a mouse model of intestinal inflammation. Thus, these results reveal a novel function of NAADP in controlling the differentiation and plasticity of CD4+ T cells.

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Ibrutinib Is an Irreversible Molecular Inhibitor of Interleukin-2 Inducible Kinase: Expanding Therapeutic Potential and Modulating a Th1 Selective Pressure in CD4 T-Cells

Blood ◽

10.1182/blood.v120.21.775.775 ◽

2012 ◽

Vol 120 (21) ◽

pp. 775-775 ◽

Cited By ~ 1

Author(s):

Jason A Dubovsky ◽

Kyle A Beckwith ◽

Jennifer A. Woyach ◽

Samantha M. Jaglowski ◽

Joshua Hessler ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mouse Model ◽

Adaptive Immunity ◽

Cd4 T Cells ◽

Research Funding ◽

Cell Receptor ◽

Receptor Activation ◽

Genetic Ablation

Abstract Abstract 775 In chronic lymphocytic leukemia (CLL), mounting evidence points to an aberrant tumor associated Th2 bias that drives leukemic cell immune evasion, promotes formation of a supportive niche microenvironment, and functionally cripples innate and adaptive immunity. The end result is a high incidence of infections which is the primary cause of mortality in CLL. This same Th2 bias is induced by many other types of cancer. Th2 CD4 T-cells are singularly dependent upon IL-2-inducible T-cell kinase (ITK) for activation whereas Th1 CD4 and CD8 T-cells have compensatory resting lymphocyte kinase (RLK) which conducts T-cell receptor activation even in the absence of ITK. Thus, a clinically viable ITK inhibitor would be ideal for targeting immune suppression associated with CLL and potentially other types of cancer. Unfortunately, no such therapeutic is currently available. Ibrutinib, a confirmed inhibitor of the Bruton's tyrosine kinase (BTK) that irreversibly blocks downstream B-cell receptor activation, has demonstrated outstanding clinical activity in phase I/II clinical trials resulting in durable remissions in CLL. Our studies unveiled a previously uncharacterized Th1 cytokine switch in ibrutinib treated CLL patients which could not be attributed to B-lymphocytes. This ibrutinib-induced Th1 T-cell skewing was confirmed using the EμTCL1 mouse model of leukemia. Such alterations in cytokine patterns were reminiscent of mouse studies in which genetic ablation of ITK subverted Th2 immunity, thereby potentiating Th1-based adaptive immunity. The striking homology between BTK and ITK combined with intriguing in silico docking studies and promising in vitro kinase inhibition profiles with ibrutinib led to the hypothesis that this could be the first clinically viable irreversible ITK inhibitor. Cellular probe assays confirmed that the active site of ITK was covalently blocked by ibrutinib at pharmacologically relevant doses. Our comprehensive molecular analyses of T-cell signaling confirmed this in the Jurkat cell line. We further confirmed both molecular and functional outcomes in primary and in vitro polarized Th1 and Th2 CD4 T-cells. We found that mutation of the ITK-Cys442 covalent binding residue for ibrutinib alleviated molecular inhibition. We also demonstrated that Th1 and CD8 T-cell restricted expression of RLK provides a compensatory platform for T-cell activation offering a molecular explanation for the selective outgrowth of cytotoxic Th1 biased immunity. We further confirmed this effect using T-cells directly derived from CLL patients. To demonstrate that ibrutinib-induced ITK inhibition had direct clinical relevance in the setting of CLL we utilized a novel listeriosis/leukemia mouse model. In this model we clearly demonstrated complete recovery of functional immunity and all ibrutinib treated mice survived a potentially lethal Listeria monocytogenes infection. Our results expose novel molecular insights into the mechanism of action of ibrutinib in the context of Th2-biased immunosuppressive leukemia. We also postulate that ibrutinib's irreversible ITK inhibitory effects may prove effective in a number of other autoimmune, inflammatory, and viral diseases, including influenza A and HIV/AIDS. Disclosures: Jaglowski: Pharmacyclics: Research Funding. Chang:Pharmacyclics, Inc.: Employment. Maddocks:Pharmacyclics: Research Funding. Buggy:Pharmacyclics: Employment, Equity Ownership. Byrd:Pharmacyclics: Research Funding.

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Co-Administration Of Gene-Modified CD4+ T Cells Targeting HLA Class I-Restricted WT1 Epitope Diversely Enhances The Antitumor Effect Mediated By Redirected T-Cell Based Adoptive Immunotherapy Against Human Leukemia

Blood ◽

10.1182/blood.v122.21.144.144 ◽

2013 ◽

Vol 122 (21) ◽

pp. 144-144

Author(s):

Hiroshi Fujiwara ◽

Fumihiro Ochi ◽

Toshiki Ochi ◽

Hiroaki Asai ◽

Yukihiro Miyazaki ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mouse Model ◽

Cd8 T Cells ◽

Adoptive Immunotherapy ◽

Cd4 T Cells ◽

Hla Class I ◽

Class I ◽

Leukemia Cells

Abstract Purpose In the context of redirected T-cell based antitumor adoptive immunotherapy, the therapeutic roles played by co-infused CD4+ T cells genetically redirected to the predefined HLA class I-restricted epitope which had been originally recognized by effector CD8+ T cells has not yet been fully discussed. In this study, using an HLA class I-restricted WT1 -specific T-cell receptor (TCR) gene transfer, we in detail examined antileukemia functionality mediated by these gene-modified CD4+ T cells co-infused with similarly gene-modified effector CD8+ T cells as the redirected T cell-based adoptive immunotherapy. Methods Using our unique retroviral vector expressing HLA-A*2402-restricted and WT1235-243-specific TCR a/b genes and shRNAs for endogenous TCRs (WT1-siTCR vector), we genetically modified both CD4+ and CD8+ T cells from the same healthy donor or leukemia patients (termed WT1-siTCR/CD4 and WT1-siTCR/CD8, respectively). First, target-responsive cellular outputs mediated by WT1-siTCR/CD4 was thoroughly examined using flowcytometry, ELISA, 51Cr-release assay, CFSE dilution assay and bioluminescence assay. Next we similarly assessed impacts of WT1-siTCR/CD4 on the antileukemia functionality mediated by concurrentWT1-siTCR/CD8 both in vitro and in vivo. Eventually, we assessed the in vivo therapeutic efficacy of combined administration of WT1-siTCR/CD8 with WT1-siTCR/CD4 using a xenografted mouse model. Results The transcription factor profile demonstrated that WT1-siTCR/CD4 turned a terminal effector, but not regulatory phenotype. Activated WT1-siTCR/CD4 expressed cell-surface CD40L. Target-responsive cytokine production profile of WT1-siTCR/CD4 represented the Th1 helper function in the context of HLA-A*2402. HLA class II molecules expressed by leukemia cells facilitated the recognition of leukemia cells by WT1-siTCR/CD4 in the context of HLA-A*2402. WT1-siTCR/CD4 displayed the delayed cytocidal activity determined by 51Cr release assay. WT1-siTCR/CD4 could produce IFN-g in response to freshly isolated leukemia cells. WT1-siTCR/CD4 displayed the leukemia trafficking activity in vivo. WT1-siTCR/CD4 represented the potential to migrate into bone marrow via CXCR4/CXCL12 axis both in vitro and in vivo. Concurrent WT1-siTCR/CD4 augmented IFN-g production and cytotoxic degranulation mediated by WT1-siTCR/CD8 in response to the cognate epitope via humoral factors. Consequently, the cytocidal activity against autologous leukemia cells mediated by WT1-siTCR/CD8 was augmented in the presence of WT1-siTCR/CD4, both of them generated from normal lymphocytes of the same patient with leukemia in a complete remission. Upon the target recognition, activated WT1-siTCR/CD4 recruited WT1-siTCR/CD8 via CCL3/4-CCR5 axis. Proliferative response and differentiation into central memory T-cell subset mediated by WT1-siTCR/CD8 in response to the cognate epitope and leukemia cells were enhanced in the presence of autologousWT1-siTCR/CD4, but not gene-modified CD4+ T cells (NGM-CD4). CD127 expression on activated WT1-siTCR/CD8 also increased in parallel to this differentiation. Co-infused WT1-siTCR/CD4 augmented the tumor trafficking and persistence of WT1-siTCR/CD8 in vivo, resulting in the greater suppression of leukemia cells in a xenografted mouse model. Finally, in the therapeutic mouse model, co-infusion of WT1-siTCR/CD8 with of WT1-siTCR/CD4 significantly suppressed the growth of inoculated leukemia cells compared to that in mice received co-infusion of WT1-siTCR/CD8 with NGM-CD4 (Fig.1). Correlation between the therapeutic efficacy and survival of infused gene-modified T cells was also observed. Conclusion In results, the combined infusion of WT1-siTCR/CD8 with WT1-siTCR/CD4, but not NGM-CD4 obviously demonstrates the enhanced antileukemia efficacy via diverse mechanisms. Now we have just started a clinical trial using gene-modified T cells with WT1-siTCR vector for the treatment of patients with refractory acute myeloid leukemia and myeloid dysplastic syndrome. Because redirected T cells employed in this trial encompassed both WT1-siTCR/CD4 and WT1-siTCR/CD8, we are planning to clinically verify the significance of WT1-siTCR/CD4 in the redirected T cell-based antileukemia adoptive immunotherapy. (Fig.1) Disclosures: No relevant conflicts of interest to declare.

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TNF-Alpha Priming Enhances CD4+ FoxP3+ Regulatory T Cell Suppressive Function in GvHD Prevention and Treatment

Blood ◽

10.1182/blood.v126.23.1885.1885 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1885-1885

Author(s):

Antonio Pierini ◽

Caitlin Moffett ◽

Dominik Schneidawind ◽

Jeanette Baker ◽

Hidekazu Nishikii ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mouse Model ◽

Peripheral Blood ◽

Activation Markers ◽

Suppressive Function ◽

Prevention And Treatment ◽

And Function

Abstract CD4+ CD25+ FoxP3+ regulatory T cells (Treg) have been shown to effectively prevent graft versus host disease (GvHD) when adoptively transferred in murine models of hematopoietic cell transplantation (HCT) and phase I/II clinical trials. Critical limitations to the clinical application of Treg are the paucity of cells and limited knowledge of the mechanism(s) of in vivo function. In physiologic conditions Treg regulate immune responses during inflammation. We hypothesized that inflammatory conditions in GvHD modify Treg characteristics and function. To test this hypothesis, we primed Treg with irradiated (3000 cGy) peripheral blood from acute GvHD (aGvHD) affected mice for 20-24 hours and then transferred these cells in a mouse model of GvHD where allogeneic T cell depleted bone marrow (TCD BM) from C57BL/6 mice was transplanted into lethally irradiated (8 Gy) BALB/c recipients together with 7.5x105 to 1x106 /animal donor derived conventional CD4+ and CD8+ T cells (Tcon). C57BL/6 Treg primed with irradiated aGvHD peripheral blood were injected at day 0 after HCT for preventing GvHD or at day +7 or +8 as GvHD treatment. Their adoptive transfer resulted in improved survival in comparison to unprimed natural occurring Treg when used for both GvHD prevention (p=0.01) and treatment (p=0.04). Moreover treatment with irradiated aGvHD peripheral blood-primed Treg did not impact graft versus tumor effects in a mouse model of T cell mediated tumor killing. BLI demonstrated that injected allogeneic Tcon completely cleared previously infused luc+ A20 tumor cells even in the presence of primed Treg (primed Treg + Tcon + A20 vs A20 alone p<0.001). Irradiated aGvHD peripheral blood-primed Treg express increased levels of activation markers with suppressive function such as CTLA4 (p<0.001) and LAG3 (p<0.05) in comparison to unprimed Treg in vitro. We also found that Treg primed with irradiated cells of aGvHD affected animals after removing the serum did not enhance the expression of the same markers (p>0.05) demonstrating that serum from aGvHD animals is required for Treg priming and function. We further tested the ability of several inflammatory cytokines that are normally secreted during GvHD such as IFN-γ, IL-6, IL-12 and TNFα to induce similar in vitro Treg activation. We found that TNFɑ selectively activated Treg without impacting CD4+ FoxP3- T cells. TNFɑ-primed Treg have increased expression of activation markers such as CD69 (p<0.0001), CD25 (p<0.0001), and LAG3 (p=0.0002), produce a greater amount of suppressive cytokines such as IL-10 (p=0.03) and TGF-β (p=0.02), and enhance the expression of homing markers such as CD62L (p=0.005) that are required for in vivo function. TNFɑ-primed Treg had increased ability to proliferate (p=0.02) and, at the same time, to suppress Tcon proliferation (p=0.04) in a mixed lymphocyte reaction against irradiated allogeneic splenocytes, while, on the contrary, TNFɑ-primed Tcon had reduced ability to proliferate in similar conditions in comparison to unprimed Tcon (p=0.0004). To test the effect of TNFɑ priming on in vivo Tcon proliferation we injected TNFɑ-primed and unprimed luc+ Tcon in allogeneic BALB/c Rag2-/- γ-chain-/- immune deficient animals that were sublethally irradiated (400 cGy). BLI at day +7 after Tcon injection revealed reduced TNFɑ-primed Tcon in vivo proliferation (p=0.01) that resulted in milder GvHD symptoms (p=0.02). Finally, in a GvHD prevention mouse model TNFɑ-primed Treg infused at 1:10 Treg/Tcon ratio resulted in improved animal survival as compared to unprimed Treg (p=0.02), demonstrating enhanced efficacy of TNFɑ priming in the in vivo function of Treg. In summary, our study demonstrates that Treg respond to TNFɑ acquiring an activated status resulting in increased function. As TNFɑ is produced by several immune cells during inflammation, our work elucidates aspects of the physiologic mechanisms of Treg function. Furthermore TNFɑ priming of Treg in vitro provides a new tool to optimize Treg cellular therapies also allowing for the use of a reduced cell number for GvHD prevention and treatment. Disclosures No relevant conflicts of interest to declare.

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Long-term effects of intermittent interleukin 2 therapy in patients with HIV infection: characterization of a novel subset of CD4+/CD25+ T cells

Blood ◽

10.1182/blood.v100.6.2159 ◽

2002 ◽

Vol 100 (6) ◽

pp. 2159-2167 ◽

Cited By ~ 45

Author(s):

Irini Sereti ◽

Hector Martinez-Wilson ◽

Julia A. Metcalf ◽

Michael W. Baseler ◽

Claire W. Hallahan ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Lymphocytes ◽

Cd4 T Cells ◽

Interleukin 2 ◽

Hiv Patients ◽

Activation Markers ◽

Cd25 Expression ◽

Cell Counts

Abstract The long-term immunologic effects of intermittent interleukin 2 (IL-2) therapy were evaluated in a cross-sectional study by comparing 3 groups: HIV-seronegative volunteers, HIV-infected (HIV+) patients receiving highly active antiretroviral therapy (HAART), and HIV+ patients receiving HAART and intermittent IL-2. Whole-blood immunophenotyping was performed to study expression of the IL-2 receptor chains on T lymphocytes and natural killer cells and to further characterize CD4+/CD25+ T cells. Increased CD25 expression, especially in CD4+ T cells but also in CD8+ T cells, without increases in expression of the β and γ chains of the IL-2 receptor was detected in the IL-2 group. Up to 79% of naive CD4+ T cells (median, 61%) from patients in the IL-2 group expressed CD25, and the number of naive CD4+/CD25+ T cells correlated positively with both the total and naive CD4+ T-cell counts. A discrete population of CD45 double intermediate RA+/RO+CD4+ cells was also preferentially expanded in the IL-2 group, and the number of these cells strongly correlated with the total CD4+ count. Despite increases in CD25 expression, T lymphocytes from patients treated with IL-2 did not have increased expression of early (CD69) or late (CD95) activation markers or evidence of recent proliferation (Ki67). Both CD4+/CD25+ and CD4+/CD25− cells from IL-2–treated HIV+ patients proliferated in response to mitogens, specific antigens, and T-cell-receptor–mediated stimuli. Thus, intermittent administration of IL-2 in HIV+ patients leads to preferential expansion of a unique subset of CD4+ T cells that may represent a critical population in T-cell homeostasis.

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