Publications by authors named "Rebekka Wehner"

49 Publications

Tumor-infiltrating plasmacytoid dendritic cells are associated with survival in human colon cancer.

J Immunother Cancer 2021 Mar;9(3)

Institute of Immunology, Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany

Background: Plasmacytoid dendritic cells (pDCs) play a key role in the induction and maintenance of antitumor immunity. Conversely, they can act as tolerogenic DCs by inhibiting tumor-directed immune responses. Therefore, pDCs may profoundly influence tumor progression. To gain novel insights into the role of pDCs in colon cancer, we investigated the frequency and clinical relevance of pDCs in primary tumor tissues from patients with colon cancer with different clinicopathological characteristics.

Methods: Immunohistochemical stainings were performed to explore the frequency of tumor-infiltrating BDCA-2 pDCs in patients with colon cancer. Statistical analyses were conducted to determine an association between the pDC density and clinicopathological characteristics of the patients. Furthermore, we used multiplex immunofluorescence stainings to evaluate the localization and phenotype of pDCs in stroma and tertiary lymphoid structures (TLS) of colon cancer tissues.

Results: An increased density of infiltrating pDCs was associated with lower Union for International Cancer Control (UICC) stages. Furthermore, a higher pDC frequency was significantly correlated with increased progression-free and overall survival of patients with colon cancer. Moreover, a lower number of coloncancer-infiltrating pDCs was significantly and independently linked to worse prognosis. In addition, we found that a proportion of pDCs shows a nuclear expression of the transcription factor interferon regulatory factor 7 (IRF7), which is characteristic for an activated phenotype. In various tumor stroma regions, IRF7 pDCs were located in the neighborhood of granzyme B-expressing CD8 T cells. Moreover, pDCs were identified as a novel component of the T cell zone of colon cancer-associated TLS, which are major regulators of adaptive antitumor immunity. A proportion of TLS-associated pDCs displayed a nuclear IRF7 expression and was preferentially located close to CD4 T cells.

Conclusions: These results indicate that higher densities of tumor-infiltrating pDCs are associated with prolonged survival of patients with colon cancer. Moreover, colon cancer-infiltrating pDCs may represent a novel prognostic factor. The colocalization of activated pDCs and T cells in tumor stroma and within TLS may contribute to the correlation between higher pDC densities and better prognosis. In addition, our findings may have implications for the design of novel immunotherapeutic strategies that are based on targeting colon cancer-infiltrating pDCs.
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http://dx.doi.org/10.1136/jitc-2020-001813DOI Listing
March 2021

Immunomodulatory Properties of Mesenchymal Stromal Cells: An Update.

Front Cell Dev Biol 2021 9;9:637725. Epub 2021 Feb 9.

Institute of Immunology, Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany.

Mesenchymal stromal cells (MSCs) are characterized by an extraordinary capacity to modulate the phenotype and functional properties of various immune cells that play an essential role in the pathogenesis of inflammatory disorders. Thus, MSCs efficiently impair the phagocytic and antigen-presenting capacity of monocytes/macrophages and promote the expression of immunosuppressive molecules such as interleukin (IL)-10 and programmed cell death 1 ligand 1 by these cells. They also effectively inhibit the maturation of dendritic cells and their ability to produce proinflammatory cytokines and to stimulate potent T-cell responses. Furthermore, MSCs inhibit the generation and proinflammatory properties of CD4 T helper (Th)1 and Th17 cells, while they promote the proliferation of regulatory T cells and their inhibitory capabilities. MSCs also impair the expansion, cytokine secretion, and cytotoxic activity of proinflammatory CD8 T cells. Moreover, MSCs inhibit the differentiation, proliferation, and antibody secretion of B cells, and foster the generation of IL-10-producing regulatory B cells. Various cell membrane-associated and soluble molecules essentially contribute to these MSC-mediated effects on important cellular components of innate and adaptive immunity. Due to their immunosuppressive properties, MSCs have emerged as promising tools for the treatment of inflammatory disorders such as acute graft-versus-host disease, graft rejection in patients undergoing organ/cell transplantation, and autoimmune diseases.
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http://dx.doi.org/10.3389/fcell.2021.637725DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900158PMC
February 2021

PD-1 Expression by Lymph Node and Intratumoral Regulatory T Cells Is Associated with Lymph Node Metastasis in Pancreatic Cancer.

Cancers (Basel) 2020 Sep 24;12(10). Epub 2020 Sep 24.

Department of Visceral, Thoracic and Vascular Surgery, Medical Faculty, University Hospital Carl Gustav Carus, TU Dresden, 01307 Dresden, Germany.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a mostly immunosuppressive microenvironment. Tumor-draining lymph nodes (TDLN) are a major site for priming of tumor-reactive T cells and also tumor metastasis. However, the phenotype and function of T cells in TDLNs from PDAC patients is unknown. In this study, lymph nodes from the pancreatic head (PH), the hepatoduodenal ligament (HDL) and the interaortocaval (IAC) region were obtained from 25 patients with adenocarcinoma of the pancreatic head. Additionally, tumors and matched blood were analyzed from 16 PDAC patients. Using multicolor flow cytometry, we performed a comprehensive analysis of T cells. CD4 T cells were the predominant T cell subset in PDAC-draining lymph nodes. Overall, lymph node CD4 and CD8 T cells had a similar degree of activation, as measured by CD69, inducible T cell co-stimulator (ICOS) and CD137 (4-1BB) expression and interferon-γ (IFNγ) secretion. Expression of the inhibitory receptor programmed death 1 (PD-1) by lymph node and tumor-infiltrating regulatory T cells (Tregs) correlated with lymph node metastasis. Collectively, Treg cells and PD-1 are two relevant components of the immunosuppressive network in PDAC-draining lymph nodes and may be particularly attractive targets for combinatorial immunotherapeutic strategies in selected patients with node-positive PDAC.
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http://dx.doi.org/10.3390/cancers12102756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7599971PMC
September 2020

Characteristics of Tumor-Infiltrating Lymphocytes Prior to and During Immune Checkpoint Inhibitor Therapy.

Front Immunol 2020 4;11:364. Epub 2020 Mar 4.

Faculty of Medicine Carl Gustav Carus, Institute of Immunology, TU Dresden, Dresden, Germany.

The tumor immune contexture plays a major role for the clinical outcome of patients. High densities of CD45RO T helper 1 cells and CD8 T cells are associated with improved survival of patients with various cancer entities. In contrast, a higher frequency of tumor-infiltrating M2 macrophages is correlated with poor prognosis. Recent studies provide evidence that the tumor immune architecture also essentially contributes to the clinical efficacy of immune checkpoint inhibitor (CPI) therapy in patients. Pretreatment melanoma samples from patients who experienced a clinical response to anti-programmed cell death protein 1 (PD-1) treatment show higher densities of infiltrating CD8 T cells compared to samples from patients that progressed during therapy. Anti-PD-1 therapy results in an increased density of tumor-infiltrating T lymphocytes in treatment responders. In addition, elevated frequencies of melanoma-infiltrating TCF7CD8 T cells are correlated with beneficial clinical outcome of anti-PD-1-treated patients. In contrast, a high density of tumor-infiltrating, dysfunctional PD-1CD38 CD8 cells in melanoma patients is associated with anti-PD-1 resistance. Such findings indicate that comprehensive tumor immune contexture profiling prior to and during CPI therapy may lead to the identification of underlying mechanisms for treatment response or resistance, and the design of improved immunotherapeutic strategies. Here, we focus on studies exploring the impact of intratumoral T and B cells at baseline on the clinical outcome of CPI-treated cancer patients. In addition, recent findings demonstrating the influence of CPIs on tumor-infiltrating lymphocytes are summarized.
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http://dx.doi.org/10.3389/fimmu.2020.00364DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7064638PMC
March 2021

Bidirectional Crosstalk Between Cancer Stem Cells and Immune Cell Subsets.

Front Immunol 2020 5;11:140. Epub 2020 Feb 5.

Faculty of Medicine Carl Gustav Carus, Institute of Immunology, TU Dresden, Dresden, Germany.

Cancer stem cells (CSCs), also known as tumor-initiating cells, are characterized by an increased capacity for self-renewal, multipotency, and tumor initiation. While CSCs represent only a small proportion of the tumor mass, they significantly account for metastatic dissemination and tumor recurrence, thus making them attractive targets for therapy. Due to their ability to sustain in dormancy, chemo- and radiotherapy often fail to eliminate cancer cells with stemness properties. Recent advances in the understanding of the tumor microenvironment (TME) illustrated the importance of the immune contexture, determining the response to therapy and clinical outcome of patients. In this context, CSCs exhibit special properties to escape the recognition by innate and adaptive immunity and shape the TME into an immunosuppressive, pro-tumorigenic landscape. As CSCs sculpt the immune contexture, the phenotype and functional properties of the tumor-infiltrating immune cells in turn influence the differentiation and phenotype of tumor cells. In this review, we summarize recent studies investigating main immunomodulatory properties of CSCs and their underlying molecular mechanisms as well as the impact of immune cells on cancer cells with stemness properties. A deeper understanding of this bidirectional crosstalk shaping the immunological landscape and determining therapeutic responses will facilitate the improvement of current treatment modalities and the design of innovative strategies to precisely target CSCs.
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http://dx.doi.org/10.3389/fimmu.2020.00140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7013084PMC
March 2021

Reliable isolation of human mesenchymal stromal cells from bone marrow biopsy specimens in patients after allogeneic hematopoietic cell transplantation.

Cytotherapy 2020 01 27;22(1):21-26. Epub 2019 Dec 27.

Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany; German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany.

Isolation of mesenchymal stromal cells (MSCs) from pretreated, hematologic patients is challenging. Especially after allogeneic hematopoietic cell transplantation (HCT), standard protocols using bone marrow aspirates fail to reliably recover sufficient cell numbers. Because MSCs are considered to contribute to processes that mainly affect the outcome after transplantation, such as an efficient lymphohematopoietic recovery, extent of graft-versus-host disease as well as the occurrence of leukemic relapse, it is of great clinical relevance to investigate MSC function in this context. Previous studies showed that MSCs can be isolated by collagenase digestion of large bone fragments of hematologically healthy patients undergoing hip replacement or knee surgeries. We have now further developed this procedure for the isolation of MSCs from hematologic patients after allogeneic HCT by using trephine biopsy specimens obtained during routine examinations. Comparison of aspirates and trephine biopsy specimens from patients after allogeneic HCT revealed a significantly higher frequency of clonogenic MSCs (colony-forming unit-fibroblast [CFU-F]) in trephine biopsy specimens (mean, 289.8 ± standard deviation 322.5 CFU-F colonies/1 × 10 total nucleated cells versus 4.2 ± 9.9; P < 0.0001). Subsequent expansion of functional MSCs isolated from trephine biopsy specimen was more robust and led to a significantly higher yield compared with control samples expanded from aspirates (median, 1.6 × 10; range, 0-2.3 × 10 P0 MSCs versus 5.4 × 10; range, 0-8.9 × 10; P < 0.0001). Using trephine biopsy specimens as MSC source facilitates the investigation of various clinical questions.
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http://dx.doi.org/10.1016/j.jcyt.2019.10.012DOI Listing
January 2020

A new synthetic toll-like receptor 1/2 ligand is an efficient adjuvant for peptide vaccination in a human volunteer.

J Immunother Cancer 2019 11 15;7(1):307. Epub 2019 Nov 15.

Department of Immunology, Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076, Tübingen, Germany.

Background: We previously showed that the bacterial lipopeptide PamCys-Ser-Ser, meanwhile established as a toll-like receptor (TLR) 1/2 ligand, acts as a strong adjuvant for the induction of virus specific CD8 T cells in mice, when covalently coupled to a synthetic peptide.

Case Presentation: We now designed a new water-soluble synthetic PamCys-derivative, named XS15 and characterized it in vitro by a TLR2 NF-κB luciferase reporter assay. Further, the capacity of XS15 to activate immune cells and stimulate peptide-specific CD8 T and NK cells by 6-sulfo LacNAc monocytes was assessed by flow cytometry as well as cytokine induction using immunoassays. The induction of a functional immune response after vaccination of a volunteer with viral peptides was assessed by ELISpot assay and flow cytometry in peripheral blood cells and infiltrating cells at the vaccination site, as well as by immunohistochemistry and imaging. XS15 induced strong ex vivo CD8 and T1 CD4 responses in a human volunteer upon a single injection of XS15 mixed to uncoupled peptides in a water-in-oil emulsion (Montanide™ ISA51 VG). A granuloma formed locally at the injection site containing highly activated functional CD4 and CD8 effector memory T cells. The total number of vaccine peptide-specific functional T cells was experimentally assessed and estimated to be 3.0 × 10 in the granuloma and 20.5 × 10 in peripheral blood.

Conclusion: Thus, in one volunteer we show a granuloma forming by peptides combined with an efficient adjuvant in a water-in-oil-emulsion, inducing antigen specific T cells detectable in circulation and at the vaccination site, after one single vaccination only. The ex vivo T cell responses in peripheral blood were detectable for more than one year and could be strongly boosted by a second vaccination. Hence, XS15 is a promising adjuvant candidate for peptide vaccination, in particular for tumor peptide vaccines in a personalized setting.
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http://dx.doi.org/10.1186/s40425-019-0796-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6858783PMC
November 2019

The Evolving Landscape of Biomarkers for Anti-PD-1 or Anti-PD-L1 Therapy.

J Clin Med 2019 Sep 25;8(10). Epub 2019 Sep 25.

National Center for Tumor Diseases (NCT), University Hospital Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany.

The administration of antibodies blocking the immune checkpoint molecules programmed cell death protein 1 (PD-1) or programmed cell death 1 ligand 1 (PD-L1) has evolved as a very promising treatment option for cancer patients. PD-1/PD-L1 inhibition has significantly enhanced expansion, cytokine secretion, and cytotoxic activity of CD4 and CD8 T lymphocytes, resulting in enhanced antitumor responses. Anti-PD-1 or anti-PD-L1 therapy has induced tumor regression and improved clinical outcome in patients with different tumor entities, including melanoma, non-small-cell lung cancer, and renal cell carcinoma. These findings led to the approval of various anti-PD-1 or anti-PD-L1 antibodies for the treatment of tumor patients. However, the majority of patients have failed to respond to this treatment modality. Comprehensive immune monitoring of clinical trials led to the identification of potential biomarkers distinguishing between responders and non-responders, the discovery of modes of treatment resistance, and the design of improved immunotherapeutic strategies. In this review article, we summarize the evolving landscape of biomarkers for anti-PD-1 or anti-PD-L1 therapy.
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http://dx.doi.org/10.3390/jcm8101534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6832659PMC
September 2019

Spheroid Culture of Mesenchymal Stromal Cells Results in Morphorheological Properties Appropriate for Improved Microcirculation.

Adv Sci (Weinh) 2019 Apr 19;6(8):1802104. Epub 2019 Feb 19.

Biotechnology Center Center for Molecular and Cellular Bioengineering TU Dresden Tatzberg 47-49 01307 Dresden Germany.

Human bone marrow mesenchymal stromal cells (MSCs) are used in clinical trials for the treatment of systemic inflammatory diseases due to their regenerative and immunomodulatory properties. However, intravenous administration of MSCs is hampered by cell trapping within the pulmonary capillary networks. Here, it is hypothesized that traditional 2D plastic-adherent cell expansion fails to result in appropriate morphorheological properties required for successful cell circulation. To address this issue, a method to culture MSCs in nonadherent 3D spheroids (mesenspheres) is adapted. The biological properties of mesensphere-cultured MSCs remain identical to conventional 2D cultures. However, morphorheological analyses reveal a smaller size and lower stiffness of mesensphere-derived MSCs compared to plastic-adherent MSCs, measured using real-time deformability cytometry and atomic force microscopy. These properties result in an increased ability to pass through microconstrictions in an ex vivo microcirculation assay. This ability is confirmed in vivo by comparison of cell accumulation in various organ capillary networks after intravenous injection of both types of MSCs in mouse. The findings generally identify cellular morphorheological properties as attractive targets for improving microcirculation and specifically suggest mesensphere culture as a promising approach for optimized MSC-based therapies.
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http://dx.doi.org/10.1002/advs.201802104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6469243PMC
April 2019

Neoadjuvant Radiochemotherapy Significantly Alters the Phenotype of Plasmacytoid Dendritic Cells and 6-Sulfo LacNAc Monocytes in Rectal Cancer.

Front Immunol 2019 29;10:602. Epub 2019 Mar 29.

Institute of Immunology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.

Neoadjuvant radiochemotherapy (nRCT) can significantly influence the tumor immune architecture that plays a pivotal role in regulating tumor growth. Whereas, various studies have investigated the effect of nRCT on tumor-infiltrating T cells, little is known about its impact on the frequency and activation status of human dendritic cells (DCs). Plasmacytoid DCs (pDCs) essentially contribute to the regulation of innate and adaptive immunity and may profoundly influence tumor progression. Recent studies have revealed that higher pDC numbers are associated with poor prognosis in cancer patients. 6-sulfo LacNAc-expressing monocytes (slanMo) represent a particular proinflammatory subset of human non-classical blood monocytes that can differentiate into DCs. Recently, we have reported that activated slanMo produce various proinflammatory cytokines and efficiently stimulate natural killer cells and T lymphocytes. slanMo were also shown to accumulate in clear cell renal cell carcinoma (ccRCC) and in metastatic lymph nodes from cancer patients. Here, we investigated the influence of nRCT on the frequency of rectal cancer-infiltrating pDCs and slanMo. When evaluating rectal cancer tissues obtained from patients after nRCT, a significantly higher density of pDCs in comparison to pre-nRCT tissue samples was found. In contrast, the density of slanMo was not significantly altered by nRCT. Further studies revealed that nRCT significantly enhances the proportion of rectal cancer-infiltrating CD8 T cells expressing the cytotoxic effector molecule granzyme B. When exploring the impact of nRCT on the phenotype of rectal cancer-infiltrating pDCs and slanMo, we observed that nRCT markedly enhances the percentage of inducible nitric oxide synthase (iNOS)- or tumor necrosis factor (TNF) alpha-producing slanMo. Furthermore, nRCT significantly increased the percentage of mature CD83 pDCs in rectal cancer tissues. Moreover, the proportion of pDCs locally expressing interferon-alpha, which plays a major role in antitumor immunity, was significantly higher in post-nRCT tissues compared to pre-nRCT tumor specimens. These novel findings indicate that nRCT significantly influences the frequency and/or phenotype of pDCs, slanMo, and CD8 T cells, which may influence the clinical response of rectal cancer patients to nRCT.
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http://dx.doi.org/10.3389/fimmu.2019.00602DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450462PMC
August 2020

Immunomodulatory effects of BRAF and MEK inhibitors: Implications for Melanoma therapy.

Pharmacol Res 2018 10 23;136:151-159. Epub 2018 Aug 23.

Department of Dermatology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany; National Centre for Tumor Diseases, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany; Skin Cancer Centre at the University Cancer Center Dresden, Germany. Electronic address:

Targeted therapy with BRAF inhibitors (BRAFi) and MEK inhibitors (MEKi) provides rapid disease control with high response rates in patients with BRAF-mutant metastatic melanoma. However, the majority of patients develop resistance to therapy during the course of therapy. Immune checkpoint inhibitors show a slower onset of action with lower response rates, with responders showing sustained response. The combination of BRAFi/MEKi and immune checkpoint inhibitors combines the hope for a fast, reliable and lasting response to therapy. Preclinical data supports this hypothesis. With the help of the PubMed database, a comprehensive search and analysis of preclinical and clinical studies on the combination of BRAFi/MEKi with immune checkpoint inhibitors was performed and yielded the following results: 1) In vivo, BRAFi and MEKi have no negative effects on immune cells; BRAFi and MEKi generate 2) an immune stimulating tumor microenvironment, 3) an increased infiltration of immune cells into the tumors, 4) a better recognition of melanoma cells by immune effector cells, and 5) a better functionality of the immune effector cells. In addition, in vivo experiments 6) demonstrated a superiority of the combination treatment compared to the individual strategies in both BRAF-mutant and BRAF wild-type melanomas. In summary, available data show that both BRAFi and MEKi have beneficial effects on the antitumor immunity and the tumor microenvironment as a whole, which is mediated by different mechanisms. Currently, clinical studies are underway to investigate combinations of BRAFi and MEKi with immune checkpoint inhibitors. The results of these studies are eagerly awaited.
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http://dx.doi.org/10.1016/j.phrs.2018.08.019DOI Listing
October 2018

Immune Monitoring of Cancer Patients Prior to and During CTLA-4 or PD-1/PD-L1 Inhibitor Treatment.

Biomedicines 2018 Mar 1;6(1). Epub 2018 Mar 1.

National Center for Tumor Diseases, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany.

Targeting the immune checkpoint receptors cytotoxic T lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), or programmed cell death 1 ligand 1 (PD-L1) represents a very attractive treatment modality for tumor patients. The administration of antibodies against these receptors can promote efficient antitumor effects and can induce objective clinical responses in about 20-40% patients with various tumor types, accompanied by improved survival. Based on their therapeutic efficiency, several antibodies have been approved for the treatment of tumor patients. However, many patients do not respond to checkpoint inhibitor therapy. Therefore, the identification of biomarkers is required to guide patient selection for this treatment modality. Here, we summarize recent studies investigating the PD-L1 expression or mutational load of tumor tissues as well as the frequency and phenotype of immune cells in tumor patients prior to and during CTLA-4 or PD-1/PD-L1 inhibitor treatment.
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http://dx.doi.org/10.3390/biomedicines6010026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5874683PMC
March 2018

Longitudinal analyses of leukemia-associated antigen-specific CD8 T cells in patients after allogeneic stem cell transplantation.

Exp Hematol 2016 Nov 26;44(11):1024-1033.e1. Epub 2016 Jul 26.

Medical Clinic I, University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment approach for patients with acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL). Graft versus leukemia (GVL) effects, which are exerted by donor T cells directed against leukemic-associated antigens (LAAs), are considered to play a crucial role in disease eradication. Although the expansion of cytotoxic T lymphocytes (CTLs) specific for cytomegalovirus (CMV) in response to an infection has been shown in multiple studies, data on CTLs mediating GVL effects are limited. To evaluate a potential increase or decrease of T lymphocytes specific for LAAs in the setting of allogeneic HSCT, we monitored leukemia-specific CD8 T cells throughout the first year after HSCT in 18 patients using streptamer technology. A broad panel of promising LAAs was selected: Wilms tumor protein, proteinase 3, receptor for hyaluronan acid-mediated motility, apoptosis regulator Bcl-2, survivin, nucleophosmin, and fibromodulin. T cells specifically directed against AML- or CLL-associated antigens were found at very low frequencies in peripheral blood. Substantial frequencies of LAA-specific T cells could not be measured at any time point by flow cytometry. In contrast, abundant CMV-pp65-specific T cells were detected in CMV-seropositive patient-recipient pairs and an increase prompted by CMV infection could be demonstrated. In conclusion, T lymphocytes with specificities for the aforementioned LAAs can only be detected in minimal quantities in the early phase after allogeneic HSCT.
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http://dx.doi.org/10.1016/j.exphem.2016.07.008DOI Listing
November 2016

Mesenchymal Stromal Cells for Treatment of Acute Steroid-Refractory Graft Versus Host Disease: Clinical Responses and Long-Term Outcome.

Stem Cells 2016 Feb 13;34(2):357-66. Epub 2015 Oct 13.

Medizinische Klinik und Poliklinik I, Universitäts KrebsCentrum, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.

Acute graft-versus-host disease (aGvHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Steroid-resistant aGvHD is associated with poor outcome, and no commonly accepted salvage therapy is available for its treatment. Here, we report 58 adult patients treated with mesenchymal stromal cells (MSCs) as salvage therapy for steroid-refractory aGvHD. Third-party MSCs expanded in platelet lysate-containing medium were transfused at a median dose of 0.99 × 10(6) cells per kg b.wt. A median of two MSC infusions were administered to each patient. Median time between the onset of aGvHD and the first infusion of MSCs was 12 days (range, 6-62 days). Most patients (79%) had grade IV aGvHD. Five patients showed complete response, five showed very good partial response, 17 showed partial response, and 31 showed no response. The estimated probability of survival after 1 year was 19%, and median survival was 69 days. Overall survival was not significantly different from that of a historical cohort of patients receiving alternative salvage therapy and no MSC infusions. In conclusion, MSC treatment on top of conventional immunosuppression was associated with an overall response rate of 47% but improved outcome in terms of survival remains to be shown.
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http://dx.doi.org/10.1002/stem.2224DOI Listing
February 2016

Impact of p38 mitogen-activated protein kinase inhibition on immunostimulatory properties of human 6-sulfo LacNAc dendritic cells.

Immunobiology 2016 Feb 10;221(2):166-74. Epub 2015 Sep 10.

Institute of Immunology, Medical Faculty, TU Dresden, Dresden, Germany; Center for Regenerative Therapies Dresden, Dresden, Germany. Electronic address:

p38 Mitogen-activated protein kinase (MAPK) plays a crucial role in the induction and regulation of innate and adaptive immunity. Furthermore, p38 MAPK can promote tumor invasion, metastasis, and angiogenesis. Based on these properties, p38 MAPK inhibitors emerged as interesting candidates for the treatment of immune-mediated disorders and cancer. However, the majority of p38 MAPK inhibitor-based clinical trials failed due to poor efficacy or toxicity. Further studies investigating the influence of p38 MAPK inhibitors on immunomodulatory capabilities of human immune cells may improve their therapeutic potential. Here, we explored the impact of the p38 MAPK inhibitor SB203580 on the pro-inflammatory properties of native human 6-sulfo LacNAc dendritic cells (slanDCs). SB203580 did not modulate maturation of slanDCs and their capacity to promote T-cell proliferation. However, SB203580 significantly reduced the production of pro-inflammatory cytokines by activated slanDCs. Moreover, inhibition of p38 MAPK impaired the ability of slanDCs to differentiate naïve CD4(+) T cells into T helper 1 cells and to stimulate interferon-γ secretion by natural killer cells. These results provide evidence that SB203580 significantly inhibits various important immunostimulatory properties of slanDCs. This may have implications for the design of p38 MAPK inhibitor-based treatment strategies for immune-mediated disorders and cancer.
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http://dx.doi.org/10.1016/j.imbio.2015.09.012DOI Listing
February 2016

Accumulation of tolerogenic human 6-sulfo LacNAc dendritic cells in renal cell carcinoma is associated with poor prognosis.

Oncoimmunology 2015 Jun 2;4(6):e1008342. Epub 2015 Mar 2.

Institute of Immunology; Medical Faculty; TU Dresden ; Dresden, Germany ; Center for Regenerative Therapies Dresden ; Dresden, Germany ; German Cancer Consortium (DKTK) ; Dresden, Germany ; German Cancer Research Center (DKFZ) ; Heidelberg, Germany.

Dendritic cells (DCs) essentially contribute to the induction and regulation of innate and adaptive immunity. Based on these important properties, DCs may profoundly influence tumor progression in patients. However, little is known about the role of distinct human DC subsets in primary tumors and their impact on clinical outcome. In the present study, we investigated the characteristics of human 6-sulfo LacNAc (slan) DCs in clear cell renal cell carcinoma (ccRCC). slanDCs have been shown to display various tumor-directed properties and to accumulate in tumor-draining lymph nodes from patients. When evaluating 263 ccRCC and 227 tumor-free tissue samples, we found increased frequencies of slanDCs in ccRCC tissues compared to tumor-free tissues. slanDCs were also detectable in the majority of 24 metastatic lymph nodes and 67 distant metastases from ccRCC patients. Remarkably, a higher density of slanDCs was significantly associated with a reduced progression-free, tumor-specific or overall survival of ccRCC patients. Tumor-infiltrating slanDCs displayed an immature phenotype expressing interleukin-10. ccRCC cells efficiently impaired slanDC-induced T-cell proliferation and programming as well as natural killer (NK) cell activation. In conclusion, these findings indicate that higher slanDC numbers in ccRCC tissues are associated with poor prognosis. The induction of a tolerogenic phenotype in slanDCs leading to an insufficient activation of innate and adaptive antitumor immunity may represent a novel immune escape mechanism of ccRCC. These observations may have implications for the design of therapeutic strategies that harness tumor-directed functional properties of DCs against ccRCC.
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http://dx.doi.org/10.1080/2162402X.2015.1008342DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4485722PMC
June 2015

Accumulation and therapeutic modulation of 6-sulfo LacNAc(+) dendritic cells in multiple sclerosis.

Neurol Neuroimmunol Neuroinflamm 2014 Oct 18;1(3):e33. Epub 2014 Sep 18.

Departments of Neurology (K.T., T.S., H.R., T.Z.) and Dermatology (C.G.), University Hospital, Dresden; Institute of Immunology (K.D., R.W., M.S.), Medical Faculty, TU Dresden; Department of Neuropathology (I.M., W.B.), University Medical Centre, Göttingen; Department of Neurology (H.T.), University Hospital, Ulm; Department of Dermatology (K.S.), University Hospital, Heidelberg; and Center for Regenerative Therapies Dresden (M.S.), Dresden, Germany.

Objective: To examine the potential role of 6-sulfo LacNAc(+) (slan) dendritic cells (DCs) displaying pronounced proinflammatory properties in the pathogenesis of multiple sclerosis (MS).

Methods: We determined the presence of slanDCs in demyelinated brain lesions and CSF samples of patients with MS. In addition, we explored the impact of methylprednisolone, interferon-β, glatiramer acetate, or natalizumab on the frequency of blood-circulating slanDCs in patients with MS. We also evaluated whether interferon-β modulates important proinflammatory capabilities of slanDCs.

Results: SlanDCs accumulate in highly inflammatory brain lesions and are present in the majority of CSF samples of patients with MS. Short-term methylprednisolone administration reduces the percentage of slanDCs in blood of patients with MS and the proportion of tumor necrosis factor-α- or CD150-expressing slanDCs. Long-term interferon-β treatment decreases the percentage of blood-circulating slanDCs in contrast to glatiramer acetate or natalizumab. Furthermore, interferon-β inhibits the secretion of proinflammatory cytokines by slanDCs and their capacity to promote proliferation and differentiation of T cells.

Conclusion: Accumulation of slanDCs in highly inflammatory brain lesions and their presence in CSF indicate that slanDCs may play an important role in the immunopathogenesis of MS. The reduction of blood-circulating slanDCs and the inhibition of their proinflammatory properties by methylprednisolone and interferon-β may contribute to the therapeutic efficiency of these drugs in patients with MS.
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http://dx.doi.org/10.1212/NXI.0000000000000033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4204231PMC
October 2014

Gamma irradiation preserves immunosuppressive potential and inhibits clonogenic capacity of human bone marrow-derived mesenchymal stromal cells.

J Cell Mol Med 2014 Jun 21;18(6):1184-93. Epub 2014 Mar 21.

Institute for Transfusion Medicine, German Red Cross Blood Donation Service North-East, Dresden, Germany.

Mesenchymal stromal cells (MSCs) are promising candidates for the treatment of graft-versus-host and autoimmune diseases. Here, by virtue of their immunosuppressive effects, they are discussed to exhibit inhibitory actions on various immune effector cells, including T lymphocytes that promote the underlying pathology. While it becomes apparent that MSCs exhibit their therapeutic effect in a transient manner, they are usually transplanted from third party donors into heavily immunocompromised patients. However, little is known about potential late complications of persisting third party MSCs in these patients. We therefore analysed the effect of gamma irradiation on the potency and proliferation of MSCs to elucidate an irradiation dose, which would allow inhibition of MSC proliferation while at the same time preserving their immunosuppressive function. Bone marrow-derived MSCs (BM-MSCs) were gamma-irradiated at increasing doses of 5, 10 and 30 Gy and subsequently assessed by colony formation unit (CFU)-assay, Annexin V-staining and in a mixed lymphocyte reaction, to assess colony growth, apoptosis and the immunosuppressive capacity, respectively. Complete loss of proliferative capacity measured by colony formation was observed after irradiation with a dose equal to or greater than 10 Gy. No significant decrease of viable cells was detected, as compared to non-irradiated BM-MSCs. Notably, irradiated BM-MSCs remained highly immunosuppressive in vitro for at least 5 days after irradiation. Gamma irradiation does not impair the immunosuppressive capacity of BM-MSCs in vitro and thus might increase the safety of MSC-based cell products in clinical applications.
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http://dx.doi.org/10.1111/jcmm.12264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4508157PMC
June 2014

Activation of dendritic cells by the novel Toll-like receptor 3 agonist RGC100.

Clin Dev Immunol 2013 2;2013:283649. Epub 2013 Dec 2.

Riboxx GmbH, Meissner Straße 191, 01445 Radebeul, Germany ; Institute of Virology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Fetscherstraße 74, 01307 Dresden, Germany.

Toll-like receptor (TLR) 3 agonists emerged as attractive candidates for vaccination strategies against tumors and pathogens. An important mechanism of action of such agonists is based on the activation of TLR3-expressing dendritic cells (DCs), which display a unique capacity to induce and stimulate T-cell responses. In this context, it has been demonstrated that targeting of TLR3 by double-stranded RNA such as poly(I:C) results in potent activation of DCs. Major disadvantages of poly(I:C) comprise its undefined chemical structure and very poor homogeneity, with subsequent unpredictable pharmacokinetics and high toxicity. In the present study, we evaluated the physicochemical properties and biological activity of the novel TLR3 agonist RGC100. RGC100 has a defined chemical structure, with a defined length (100 bp) and molecular weight (64.9 KDa) and a good solubility. RGC100 is stable in serum and activates myeloid DCs through TLR3 targeting, as evidenced by gene silencing experiments. Activation of mouse and human myeloid CD1c(+) DCs by RGC100 leads to secretion of several proinflammatory cytokines. In addition, RGC100 improves the ability of CD1c(+) DCs to stimulate T-cell proliferation. Due to its physicochemical properties and its immunostimulatory properties, RGC100 may represent a promising adjuvant for prophylactic and therapeutic vaccination strategies.
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http://dx.doi.org/10.1155/2013/283649DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3878805PMC
August 2014

Mesenchymal stromal cells from patients with myelodyplastic syndrome display distinct functional alterations that are modulated by lenalidomide.

Haematologica 2013 Nov 28;98(11):1677-85. Epub 2013 May 28.

The contribution of the bone marrow microenvironment in myelodysplastic syndrome is controversial. We therefore analyzed the functional properties of primary mesenchymal stromal cells from patients with myelodysplastic syndrome in the presence or absence of lenalidomide. Compared to healthy controls, clonality and growth were reduced across all disease stages. Furthermore, differentiation defects and particular expression of adhesion and cell surface molecules (e.g. CD166, CD29, CD146) were detected. Interestingly, the levels of stromal derived factor 1-alpha in patients' cells culture supernatants were almost 2-fold lower (P<0.01) than those in controls and this was paralleled by a reduced induction of migration of CD34(+) hematopoietic cells. Co-cultures of mesenchymal stromal cells from patients with CD34(+) cells from healthy donors resulted in reduced numbers of cobblestone area-forming cells and fewer colony-forming units. Exposure of stromal cells from patients and controls to lenalidomide led to a further reduction of stromal derived factor 1-alpha secretion and cobblestone area formation, respectively. Moreover, lenalidomide pretreatment of mesenchymal stromal cells from patients with low but not high-risk myelodysplastic syndrome was able to rescue impaired erythroid and myeloid colony formation of early hematopoietic progenitors. In conclusion, our analyses support the notion that the stromal microenvironment is involved in the pathophysiology of myelodysplastic syndrome thus representing a potential target for therapeutic interventions.
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http://dx.doi.org/10.3324/haematol.2013.083972DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3815166PMC
November 2013

TLR7/8 agonists trigger immunostimulatory properties of human 6-sulfo LacNAc dendritic cells.

Cancer Lett 2013 Jul 9;335(1):119-27. Epub 2013 Feb 9.

Institute of Immunology, Medical Faculty, Technical University of Dresden, Dresden, Germany.

Imiquimod and resiquimod represent Toll-like receptor (TLR) 7 and 8 agonists, which emerged as attractive candidates for tumor therapy. To elucidate immune cells, which mainly contribute to TLR7/8-mediated antitumoral activity, we investigated the impact of imiquimod and resiquimod on native human 6-sulfo LacNAc (slan) dendritic cells (DCs). We found that both TLR7/8 agonists significantly improve the release of various proinflammatory cytokines by slanDCs and promote their tumor-directed cytotoxic activity. Furthermore, resiquimod efficiently augmented the ability of slanDCs to stimulate T cells and natural killer cells. These results indicate that imiquimod and resiquimod trigger various immunostimulatory properties of slanDCs, which may contribute to their antitumor effects.
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http://dx.doi.org/10.1016/j.canlet.2013.02.003DOI Listing
July 2013

Reconstitution of interleukin-17-producing T helper cells after allogeneic hematopoietic cell transplantation.

Biol Blood Marrow Transplant 2013 Mar 30;19(3):357-65. Epub 2012 Nov 30.

Department of Medicine I, University Hospital Carl Gustav Carus, Fetscherstrasse 74, Dresden, Germany.

Interleukin 17A (IL-17)-producing CD4(+) T helper type 17 (Th17) cells have recently drawn attention as possible effector cells of acute graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT) in murine models. Their role after allogeneic HCT in humans is unknown. In this prospective study, Th17, Th1/17, and Th1 cells were quantified in the peripheral blood of 80 patients within the first 3 months after allogeneic HCT using intracellular cytokine staining and flow cytometry. Within the observation period, Th1, Th1/17, and Th17 cells did not reconstitute to levels of healthy control subjects. In contrast to Th1 cells, no further expansion of Th1/17 and Th17 cells was observed during the first month after HCT. Antithymocyte globulin during conditioning significantly reduced the frequency of Th1/17 and Th17 cells but not of Th1 cells. Acute GVHD was not associated with significant changes in the size of the Th1, Th1/17, or Th17 cell subsets. Cytomegalovirus reactivation triggered the expansion of all T helper subsets, and Th1 cells showed the strongest increase. In contrast, no significant changes were found in the T helper cell compartment of patients with bacterial infections compared with time-matched control subjects. In conclusion, quantitative reconstitution of Th1, Th1/17, and Th17 cells is impaired within the first 3 months after HCT, especially when antithymocyte globulin is administered during conditioning. Cytomegalovirus reactivation, but not acute GVHD or bacterial infection, triggered the absolute expansion of these T cell subsets.
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http://dx.doi.org/10.1016/j.bbmt.2012.11.018DOI Listing
March 2013

Impact of chemotherapeutic agents on the immunostimulatory properties of human 6-sulfo LacNAc+ (slan) dendritic cells.

Int J Cancer 2013 Mar 16;132(6):1351-9. Epub 2012 Nov 16.

Medical Faculty, Institute of Immunology, Technical University of Dresden, Dresden, Germany.

Chemotherapy is an important treatment modality for many patients with advanced cancer. Recent data revealed that certain chemotherapeutic agents differentially affect maturation, cytokine production and T-cell stimulatory capacity of dendritic cells (DCs), which play a crucial role in the induction of antitumor immunity. Whereas most reports are based on mouse or human monocyte-derived DCs, studies investigating the direct effect of chemotherapeutic drugs on native human DCs are rather limited. Here, we evaluated the impact of various chemotherapeutic drugs on the immunostimulatory properties of 6-sulfo LacNAc(+) (slan) DCs, representing a major subpopulation of human blood DCs. Because of their various antitumor effects, slanDCs may essentially contribute to the immune defense against tumors. We demonstrated that doxorubicin and vinblastine significantly impair the release of tumor necrosis factor-α, interleukin (IL)-6 and IL-12 by slanDCs. Functional data revealed that both drugs inhibit slanDC-mediated proliferation of T lymphocytes and their capacity to differentiate naive CD4(+) T cells into proinflammatory T-helper type I cells. Furthermore, these agents markedly suppressed the ability of slanDCs to stimulate interferon-γ secretion by natural killer (NK) cells. In contrast, paclitaxel, mitomycin C and methotrexate sustained the ability of slanDCs to produce proinflammatory cytokines and their potential to activate T-lymphocytes and NK cells. These results indicate that doxorubicin and vinblastine impair the ability of native human DCs to stimulate important immune effector cells, whereas methotrexate, mitomycin C and paclitaxel maintain their immunostimulatory properties. These novel findings may have implications for the design of treatment modalities for tumor patients combining immunotherapeutic strategies and chemotherapy.
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http://dx.doi.org/10.1002/ijc.27786DOI Listing
March 2013

Differential effects of mixed lymphocyte reaction supernatant on human mesenchymal stromal cells.

Exp Hematol 2012 Nov 1;40(11):934-44. Epub 2012 Aug 1.

Medical Clinic and Polyclinic I, University Hospital Carl Gustav Carus, Dresden, Germany.

The concept that mesenchymal stromal cells (MSCs), a component of the hematopoietic microenvironment, can be a target for alloreactive effector cells in the context of graft-vs-host disease has not been investigated in detail. Mixed lymphocyte reaction (MLR) supernatant was used to mimic the inflammatory milieu induced by an allogeneic immune response in vitro. In addition to phenotype and proliferation, we monitored MSC differentiation, gene expression, and support of CD34(+) hematopoietic stem and progenitor cells after priming with MLR supernatant. Priming of MSCs with MLR supernatant led to an 11-fold decrease in cobblestone area-forming cells in the 4-week coculture (p < 0.05) and a threefold decrease of colony-forming unit macrophage in the colony-forming cell assay (p < 0.05). MSC proliferation over 8 days was increased 2.5-fold (p < 0.05). Osteogenic differentiation was enhanced, while adipogenesis was concurrently suppressed. In addition, the surface expression of HLA-DR and intercellular adhesion molecule-1 was increased 20-fold (p = 0.06) and 45-fold (p < 0.05), respectively. This was associated with increased adhesion of hematopoietic stem and progenitor cells to MLR-treated MSCs. In summary, our data shed light on the dysfunction of the stromal environment during graft-vs-host disease, possibly aggravating cytopenia and leading to an enhanced immunogenicity of MSCs.
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http://dx.doi.org/10.1016/j.exphem.2012.07.011DOI Listing
November 2012

Impact of lenalidomide on the functional properties of human mesenchymal stromal cells.

Exp Hematol 2012 Oct 15;40(10):867-76. Epub 2012 Jun 15.

Medical Clinic and Polyclinic I, University Hospital, Dresden, Germany.

Objective: Lenalidomide (LEN) has emerged as a promising therapeutic option for the management of various hematologic malignancies. Although its direct mechanisms of action on malignant cells have been studied intensively, its effects on the stromal compartment of bone marrow have not yet been analyzed systematically. Therefore, we investigated whether LEN alters the functional capacity of mesenchymal stromal cells (MSCs) as the main cellular component of the bone marrow microenvironment. In addition to their growth and differentiation characteristics, we focused on the ability of MSC to modulate T-cell function and support hematopoietic stem cells (HSCs).

Materials And Methods: Bone marrow-derived MSCs were exposed to LEN (10 μM), and differences in proliferation, phenotype, inhibition of T-cell proliferation, and differentiation capacity were analyzed. A Boyden chamber assay was used to test the migratory potential of HSC toward the conditioned medium of LEN-treated or untreated MSCs, and the stromal cell-derived factor-1 (SDF-1) concentrations in these supernatants were determined by enzyme-linked immunosorbent assay.

Results: Treatment of MSCs with LEN did not affect their growth rate, proliferation, osteogenic and adipogenic differentiation potential, or capacity to inhibit T-cell proliferation. However, LEN treatment increased the average of mean fluorescence intensity of CD29 and CD73 by 15 and 22%, respectively. Interestingly, LEN reduced SDF-1 by MSCs by 32% compared to that of control cells. As a functional consequence, the serum-free supernatant of LEN-treated MSCs had a significantly lower potential to induce the directed migration of CD34(+) HSCs.

Conclusion: LEN can modulate the expression of cell surface molecules and the chemokine secretion of MSCs in vitro. These effects might contribute to the clinical effects of the compound in vivo for patients with hematological malignancies.
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http://dx.doi.org/10.1016/j.exphem.2012.06.004DOI Listing
October 2012