Salvage therapy with high-dose cytarabine and mitoxantrone in combination with all-trans retinoic acid and gemtuzumab ozogamicin in acute myeloid leukemia refractory to first induction therapy.

Outcome of patients with primary refractory acute myeloid leukemia remains unsatisfactory. We conducted a prospective phase II clinical trial with gemtuzumab ozogamicin (3 mg/m(2) intravenously on day 1), all-trans retinoic acid (45 mg/m(2) orally on days 4-6 and 15 mg/m(2) orally on days 7-28), high-dose cytarabine (3 g/m(2)/12 h intravenously on days 1-3) and mitoxantrone (12 mg/m(2) intravenously on days 2-3) in 93 patients aged 18-60 years refractory to one cycle of induction therapy. Primary end point of the study was response to therapy; secondary end points included evaluation of toxicities, in particular, rate of sinusoidal obstruction syndrome after allogeneic hematopoietic cell tr…

Gene Therapy With a High-Affinity Single-Chain p53-Specific TCR Mediates Potent Anti-Tumor Response Without Inducing Gvhd In Vivo

Abstract The adoptive transfer of tumor-reactive cells is a promising approach in the treatment of human malignancies, but the challenge of isolating T cells with high-avidity for tumor antigens in each patient has limited its widespread application. Using HLA-A2.1 transgenic mice, we have demonstrated the feasibility of T-cell receptor (TCR) gene transfer into T cells to circumvent self-tolerance to the widely expressed human p53(264-272) tumor-associated antigen and developed approaches to generate high-affinity CD8-independent TCR. However, a safety concern of TCR gene transfer is the risk of pairing between introduced and the naturally expressed endogenous TCR chains, resulting in the g…

Targeting components of the alternative NHEJ pathway sensitizes KRAS mutant leukemic cells to chemotherapy.

Abstract Activating KRAS mutations are detected in a substantial number of hematologic malignancies. In a murine T-cell acute lymphoblastic leukemia (T-ALL) model, we previously showed that expression of oncogenic Kras induced a premalignant state accompanied with an arrest in T-cell differentiation and acquisition of somatic Notch1 mutations. These findings prompted us to investigate whether the expression of oncogenic KRAS directly affects DNA damage repair. Applying divergent, but complementary, genetic approaches, we demonstrate that the expression of KRAS mutants is associated with increased expression of DNA ligase 3α, poly(ADP-ribose) polymerase 1 (PARP1), and X-ray repair cross-comp…

Human leukocyte elastase counteracts matrix metalloproteinase-7 induced apoptosis resistance of tumor cells.

Matrix metalloproteinase-7 (MMP-7/Matrilysin) is a component of the tumor microenvironment associated with malignant progression. Its expression in tumors protects tumor cells from CD95-mediated apoptosis and the cytotoxic activity of tumor specific CD8(+) T cells. In the present study, we show that human leukocyte elastase (HLE) secreted by polymorphonuclear leukocytes cleaves MMP-7 resulting in loss of enzymatic activity. The anti-apoptotic effect of MMP-7 is reduced in the presence of HLE for CD95-, doxorubicin- and CTL-mediated apoptosis. Our data indicates that HLE may be a natural inactivator of MMP-7 which can counteract MMP-7-induced apoptosis resistance.

In Vitro Stimulation and Expansion of Human Tumour-Reactive CD8+ Cytotoxic T Lymphocytes by Anti-CD3/CD28/CD137 Magnetic Beads

Adoptive immunotherapy with tumour-reactive CD8(+) cytotoxic T lymphocytes (CTLs) requires efficient in vitro approaches allowing the expansion of CTLs to large numbers prior infusion. Here, we investigated the antigen-independent activation and the expansion of human T cells in peripheral blood mononuclear cells (PBMCs) and in tumour-reactive CTLs using Dynabeads coated with monoclonal antibodies to CD3 and to the costimulatory molecules CD28 and CD137 (4-1BB). T cells in PBMCs showed an increased expansion rate of 15- to 17-fold during a 2-week culture period using antibody-conjugated beads with interleukin-2 (IL-2) added versus IL-2 alone. No significant difference between CD3/CD28 beads…

CD8-Depleted Donor-Lymphocyte Infusions After T-Cell Depleted Allogeneic Hemopoietic Stem Cell Transplantation

Anti-p53-directed immunotherapy of malignant disease

Mutation and aberrant expression of the p53 tumour suppressor protein are the most frequent molecular alterations in human malignancy. Peptides derived from the p53 protein and presented by major histocompatibility complex molecules for T-cell recognition could serve as universal tumour-associated antigens for cancer immunotherapy. Because p53 normally functions as a ubiquitously expressed self-protein, controlling cell-cycle progression and apoptosis, it also represents a paradigm target molecule for tumour-reactive yet self-antigen-specific T cells. Tailoring p53-based cancer immunotherapy thus requires both interference with p53-specific self-tolerance and induction of the entire reperto…

The molecular basis of cancer immunotherapy by cytotoxic T lymphocytes.

The disappointing clinical results of cancer immunotherapy of the past few decades have not diminished the optimism about the potential of the new generation of immunotherapeutic strategies towards treatment of malignant disease. Tremendous progress has been made over recent years in unveiling the molecular basis of antigen presentation and recognition by cytotoxic T lymphocytes (CTL). The molecular concepts that have emerged from these studies have led to the design of novel anticancer vaccines and CTL-based immunotherapeutics. This review is to highlight the current molecular insights of antigen presentation and CTL recognition/activation, and their impact on the rational design of therap…

Expression Of FLT3-ITD Dysregulates The DBC1-Sirt1-p53 Signaling and Promotes Therapy Resistance

Abstract Background SIRT1 is a NAD+ dependent histone deacetylase, which has been shown to act as an important regulator of apoptosis, DNA-repair and is involved in the maintenance of genetic integrity under conditions of cellular stress. Beside deacetylation of histones H4K16, SIRT1 has numeral other substrates including KU70, FOXO1 or p53. SIRT1 deacetylates p53 at lysine 382 thereby reducing its transcriptional activity followed by loss of p53 dependent apoptosis in response to cell damage. The activity of SIRT1 is negatively regulated by DBC1 (Deleted in Breast Cancer 1) and involves protein–protein interaction (Kim et al., Nature 2008). Recent reports have demonstrated increased expres…

Targeting p53, hdm2, and CD19: vaccination and immunologic strategies.

Peptides presented by class I major histocompatibility complex (MHC) molecules and derived from normal self-proteins that are expressed at elevated levels by cells from a variety of human (Hu) malignancies provide, in theory, potential target antigens for a broad-spectrum, cytotoxic T lymphocyte (CTL)-based immunotherapy of cancer and hematologic malignancies. However, as such tumor- and leukemia-associated self-proteins are also expressed at low levels in some types of normal tissues, such as thymus, spleen and lymphohemopoietic cells, these self-MHC-self-peptide complexes may also represent thymic and/or peripheral tolerogens, thereby preventing immune responses. This is particularly true…

Activation of silent mating type information regulation 2 homolog 1 by human chorionic gonadotropin exerts a therapeutic effect on hepatic injury and inflammation

Incidence and prevalence of inflammatory liver diseases has increased over the last years, but therapeutic options are limited. Pregnancy induces a state of immune tolerance, which can result in spontaneous improvement of clinical symptoms of certain autoimmune diseases including autoimmune hepatitis (AIH). We investigated the immune-suppressive mechanisms of the human pregnancy hormone, chorionic gonadotropin (hCG), in the liver. hCG signaling activates silent mating type information regulation 2 homolog 1 (SIRT1), which deacetylates forkhead box o3 (FOXO3a), leading to repression of proapoptotic gene expression, because the immunosuppressive consequence attributed to the absence of caspas…

Criteria for defining a complete remission in acute myeloid leukaemia revisited. An analysis of patients treated in HOVON-SAKK co-operative group studies

Complete remission (CR) in patients with acute myeloid leukaemia (AML) is the primary endpoint for the evaluation of induction treatment and treatment strategies. However, the choice and application of the criteria for a haematological CR can often become a subject of debate because of regeneration more than 5% blasts may be present at the time of response evaluation; platelet and neutrophil recovery may be incomplete and marrow cellularity can vary. This study examined the individual parameters for CR in 1250 adult patients with de novo AML treated according to three successive study protocols. Patients with < or =5% blasts showed the best overall survival (OS) and the lowest relapse risk …

Phenotype, Function, and Safety of a p53 TCR Bicistronic GMP-Suitable Retroviral Construct.

Abstract Malignant transformation of normal cells is frequently correlated with the involvement of so called tumor-associated antigens (TAA). Such proteins, that are often overexpressed in tumor cells, can be recognized by cytotoxic CD8+ T cells (CTL) if presented as peptides on MHC (Major-Histocompatibility-Complex)-class I molecules. Due to self-tolerance mechanisms, the peripheral T cell repertoire is devoid of efficient TAA-specific, tumor-reactive CTL with high affinity, limiting the successful development of antigen-specific immunotherapeutic strategies based on such tumor-reactive T cells. The aim of this project is the preclinical development of an adoptive immunotherapy against p53…

Safety and efficacy of Temsirolimus in combination with Bendamustine and Rituximab in relapsed mantle cell and follicular lymphoma

In this phase I/II study, we explored the combination of Temsirolimus with Bendamustine and Rituximab (BeRT) in patients with r/r follicular lymphoma (FL) or mantle cell lymphoma (MCL). Patients with 1-3 prior therapies received Bendamustine (90 mg/m(2), day 1+2) and Rituximab (375 mg/m(2), day 1) with Temsirolimus in doses from 25 to 75 mg added on day 1, 8, 15 of a 28-day cycle. Fifteen (11 MCL, 4 FL) patients were included in the phase I. Median age was 73 years and median pretreatment number was 2. No formal dose-limiting toxicity was observed. Dominant non-hematological side effects were fatigue in 11 (73%), nausea in 9 (60%), mucositis in 7 (47%) and vomiting in 6 patients (40%). Coug…

Strong and sustained effector function of memory- versus naïve-derived T cells upon T-cell receptor RNA transfer: Implications for cellular therapy

Current protocols used to select CMV-specific T cells for adoptive immunotherapy focus on virus-specific memory T cells from seropositive donors. However, this strategy is not feasible in patients undergoing allogeneic haematopoietic stem-cell transplantation (HSCT) from CMV-seronegative donors. Here, we redirected T cells of CMV-seronegative donors with a human genetically engineered TCR recognizing an HLA-A*0201-binding peptide epitope of CMVpp65. To facilitate clinical translation of this approach, we used a non-viral expression system based on in vitro transcribed RNA and electroporation. Although memory and naive-derived T-cell subsets were both efficiently transfected by TCR-RNA, memo…

Functionally Altered GPI-Anchor Negative Treg Following Alemtuzumab-Based T-Cell Depletion Are Associated with Acute Gvhd.

Abstract Abstract 3059 Introduction: The monoclonal anti-CD52antibody Alemtuzumab is frequently used for T-cell depletion (TCD) in the context of allogeneic hematopoietic stem cell transplantation (HSCT) to prevent graft versus host disease (GVHD). We previously demonstrated the long term persistence of functionally impaired glycosylphosphatidylinositol (GPI)-anchor negative effector T-cells in patients receiving high dose (100mg) Alemtuzumab in combination with a dose reduced conditioning regimen (Fludarabin + Melpahlan) (Meyer, Wagner et al. BMT 2010). Despite of Alemtuzumab-mediated TCD, half of our patients developed acute GVHD. Since regulatory T cells (Treg) play a major role for cont…

Control Of Organ Transplant-Associated Graft-versus-Host Disease By Activated Host Lymphocyte Infusions

Background Prolonged persistence of donor-derived T cells after organ transplantation has been proposed to improve long-term allograft survival. However, surviving transplant-derived T cells are also able to mediate devastating graft-versus-host disease (GvHD). Currently, GvHD after organ transplantation is usually refractory to conventional therapy and the disease outcome fatal. Methods Graft-reactive host T cells were generated ex vivo from a patient suffering from a severe and refractory liver-transplant-associated GvHD. To control GvHD, activated alloreactive host T cells were repetitively retransferred into the patient (activated host lymphocyte infusion [aHLI]). Results Adoptive trans…

Obinutuzumab (GA101) in Combination with Pixantrone for the Treatment of Patients with Relapsed Aggressive B-Cell Lymphoma:Â a Phase II Trial (GOAL)

Abstract Background: A substantial proportion of patients fail first line treatment of diffuse large B-cell lymphoma. Currently available salvage therapies are often ineffective and cannot be tolerated, especially for elderly patients. Thus, probably less than 25% of patients achieve a long lasting remission. Regimens like gemcitabine/oxaliplatin, or bendamustin, both in combination with rituximab are available for elderly or after failure of HDT, however induce only short lived responses. Obinutuzumab (GA101) is a type II anti-CD20 antibody, with preclinical evidence of superiority over rituximab in xenograft models of MCL and DLBCL. Recently a large phase III trial failed to show a benefi…

SIRT1 prevents genotoxic stress-induced p53 activation in acute myeloid leukemia

SIRT1 is an important regulator of cellular stress response and genomic integrity. Its role in tumorigenesis is controversial. Whereas sirtuin 1 (SIRT1) can act as a tumor suppressor in some solid tumors, increased expression has been demonstrated in many cancers, including hematologic malignancies. In chronic myeloid leukemia, SIRT1 promoted leukemia development, and targeting SIRT1 sensitized chronic myeloid leukemia progenitors to tyrosine kinase inhibitor treatment. In this study, we investigated the role of SIRT1 in acute myeloid leukemia (AML). We show that SIRT1 protein, but not RNA levels, is overexpressed in AML samples harboring activating mutations in signaling pathways. In FMS-l…

Antifungal drugs influence neutrophil effector functions

There is a growing body of evidence for immunomodulatory side effects of antifungal agents on different immune cells, e.g., T cells. Therefore, the aim of our study was to clarify these interactions with regard to the effector functions of polymorphonuclear neutrophils (PMN). Human PMN were preincubated with fluconazole (FLC), voriconazole (VRC), posaconazole (POS), isavuconazole (ISA), caspofungin (CAS), micafungin (MFG), conventional amphotericin B (AMB), and liposomal amphotericin B (LAMB). PMN then were analyzed by flow cytometry for activation, degranulation, and phagocytosis and by dichlorofluorescein assay to detect reactive oxygen species (ROS). Additionally, interleukin-8 (IL-8) re…

Gen-Immuntherapie zur Gen-Immuntherapie zur Behandlung von Malignomen Behandlung von Malignomen

Entartete Zellen unterliegen, so eine derzeitige Hypothese, der auseren Kontrolle durch das Immunsystem. Dies ist in der Lage, von Tumorzellen prozessierte und uber Haupthistokompatibilitatskomplexe (MHC) prasentierte Peptide via T-Zellen zu erkennen. Da Tumorzellen sich bei der Prasentation von Peptiden in den MHC-Komplexen durch Peptid-Quantitat und/oder Peptid-Qualitat (so genannte Tumorantigene) von den normalen Zellen unterscheiden, kann dies zu ihrer Erkennung und Zerstorung fuhren. Kommt es zur Manifestation eines Malignoms, so hat offensichtlich diese immunologische Kontrolle versagt. Die Grunde hierfur sind vielfaltig: Verlust der Fahigkeit zur Prasentation von Tumorantigenen, redu…

A Role for NFAT in Innate Immunity: Neutrophil Effector Functions in Patients after Allogeneic Hematopoietic Stem Cell Transplantation Under Cyclosporine Α Treatment

Abstract Background and Aims: Patients after allogeneic hematopoietic stem cell transplantation (HSCT) suffer from immunodeficiency, in part due to long-term immunosuppressive medication e.g. by calcineurin inhibitors like cyclosporine A (CsA). Additionally, these patients have an increased risk for opportunistic fungal infections like invasive aspergillosis (IA). The nuclear factor of activated T cells (NFAT) is known as an important transcription factor in signaling-pathways downstream of calcineurin in the adaptive immune systems, e.g. in T cells, but also plays an important role in innate immune response as indicated by recent data in rodent models. These studies showed a relevant impac…

Increasing functional avidity of TCR-redirected T cells by removing defined N-glycosylation sites in the TCR constant domain

Adoptive transfer of T lymphocytes transduced with a T cell receptor (TCR) to impart tumor reactivity has been reported as a potential strategy to redirect immune responses to target cancer cells (Schumacher, T.N. 2002. Nat. Rev. Immunol. 2:512-519). However, the affinity of most TCRs specific for shared tumor antigens that can be isolated is usually low. Thus, strategies to increase the affinity of TCRs or the functional avidity of TCR-transduced T cells might be therapeutically beneficial. Because glycosylation affects the flexibility, movement, and interactions of surface molecules, we tested if selectively removing conserved N-glycoslyation sites in the constant regions of TCR alpha or …

Cleavage of CD95 by matrix metalloproteinase-7 induces apoptosis resistance in tumour cells

The ability of tumour cells to resist apoptosis-inducing signals by cytotoxic T cells may decide the success or failure of tumour elimination. An important effector of apoptosis is the CD95/CD95 ligand system (APO-1/Fas) that mediates perforin-independent cytotoxic T-cell killing of tumour cells. We propose a new strategy by which tumour cells can resist CD95-induced apoptosis. We identified matrix metalloproteinase-7, MMP-7 (Martilysin), as the first physiologically relevant protease that can specifically cleave CD95. MMP-7 is of unique importance because it is produced by the tumour cells themselves at early stages of tumour development. Microsequencing of the positions in CD95 cleaved by…

Alloreactive and leukemia-reactive T cells are preferentially derived from naive precursors in healthy donors: implications for immunotherapy with memory T cells.

Background HLA mismatch antigens are major targets of alloreactive T cells in HLA-incompatible stem-cell transplantation, which can trigger severe graft- versus -host disease and reduce survival in transplant recipients. Our objective was to identify T-cell subsets with reduced in vitro reactivity to allogeneic HLA antigens. Design and Methods We sorted CD4 and CD8 T-cell subsets from peripheral blood by flow cytometry according to their expression of naive and memory markers CD45RA, CD45RO, CD62L, and CCR7. Subsets were defined by a single marker to facilitate future establishment of a clinical-grade procedure for reducing alloreactive T-cell precursors and graft- versus -host disease. T c…

Phenotypic and functional characterization of neutrophils and monocytes from patients with myelodysplastic syndrome by flow cytometry.

Myelodysplastic syndrome (MDS) is a clonal stem cell disorder frequently associated with inefficient granulopoiesis showing dysplastic polymorphonuclear neutrophils (PMNs). To assess PMN functionality in MDS in a clinical routine setting, 30 MDS patients and ten healthy volunteers were analyzed for PMN and monocyte phenotype and function (degranulation, CD62L shedding, oxidative burst and phagocytosis) upon stimulation with lipopolysaccharide by multi-color flow cytometry (MCFC). Our data show a heterogeneous pattern for CD66, CD16 and CD64 expression on PMNs of MDS patients. CD62L shedding rate and CD66 degranulation were reduced. Interestingly, we detected correlations between the WHO ada…

Idelalisib Impairs TREM-1 and TLR Mediated Neutrophil Activation

Abstract Introduction: Polymorphonuclear neutrophils (PMN) play an essential role in innate inflammatory processes. Their functions are strictly regulated and many activating / inhibiting mechanisms along with their pathways are only incompletely understood. Besides toll-like receptors (TLR) and NOD-like receptors (NLR), triggering receptor expressed on myeloid cells (TREM)-1 is implicated in innate immune activation of these cells and plays a role in infectious as well as non-infectious conditions. Activation of TREM-1 results in release of pro-inflammatory chemokines and cytokines, increased surface expression of cell activation markers and degranulation. In TREM-1 downstream pathways and…

Rituximab combined with DexaBEAM followed by high dose therapy as salvage therapy in patients with relapsed or refractory B-cell lymphoma: mature results of a phase II multicentre study.

Summary Salvage therapy followed by high-dose therapy (HDT) remains a mainstay for patients with relapsed lymphoma, however no optimal regimen has been defined. Here we report on the results of R-DexaBEAM (rituximab, dexamethasone, carmustine, etoposide, cytarabine, melphalan) followed by HDT. Patients aged 18–65 years, Eastern Cooperative Oncology Group performance score 0–2, with relapsed/refractory B-cell non-Hodgkin lymphoma (NHL) were eligible. R-Dexa-BEAM was given for two cycles followed by stem cell mobilization and HDT. Primary endpoint of the trial was progression-free-survival (PFS). One hundred and three patients were included: aggressive NHL (aNHL): diffuse large B-cell lymphom…

Temsirolimus in Combination with Bendamustine and Rituximab (BeRT) for the Treatment of Relapsed Mantle Cell and Follicular Lymphoma: Final Phase I/II Results

Abstract Background: mTOR inhibition has been shown to be effective in various subtypes of malignant lymphomas (Smith et al, JCO 2010). Furthermore, in relapsed MCL a phase III trial demonstrated superiority of Temsirolimus to chemotherapy. Although novel treatment options as Ibrutinib have changed the treatment landscape for MCL, no curative potential could be shown for this approach and novel concepts continue to be needed. Several trials provided promising results when Temsirolimus is combined with agents like Rituximab (Ansell et al, Lancet Oncology 2011) or chemoimmunotherapy, as shown in part I (phase I) of the reported trial (Hess, Leukemia, 2015). We now report the final analysis of…

Final report of the efficacy and safety of gemtuzumab ozogamicin (Mylotarg) in patients with CD33-positive acute myeloid leukemia in first recurrence

BACKGROUND In this study, the authors analyzed the efficacy and safety of gemtuzumab ozogamicin (GO) (Mylotarg®), an antibody-targeted chemotherapy for CD33-positive acute myeloid leukemia (AML). METHODS Patients with CD33-positive AML in first recurrence were entered in 3 open-label, single-arm, Phase II studies. Patients received monotherapy with GO 9 mg/m2 as a 2-hour intravenous infusion in 2 doses separated by 2 weeks. Patients were evaluated for remission, survival, and treatment-emergent adverse events. RESULTS Two hundred seventy-seven patients (median age, 61 yrs) were treated with GO, and 71 patients (26%) achieved remission, which was defined as ≤ 5% blasts in the bone marrow wit…

Increasing Functional Avidity of T Cell Receptor (TCR)-Redirected T Cells by Removing Defined N-Glycoslyation Sites in the Constant Domain of Introduced TCR Chains.

Abstract Adoptive transfer of T lymphocytes transduced with a TCR to impart tumor reactivity has been reported as potential strategy to redirect immune responses to target cancer cells. However, the affinities of most TCRs specific for shared tumor antigens that can be isolated are usually low, in part reflecting the nature of the targeted tumor antigens which are self-proteins. Thus strategies that can increase the affinity or functional avidity of TCRs to be used in therapy to transduce T cells might be therapeutically beneficial. However, current strategies for increasing TCR affinity require extensive and usually random mutagenesis followed by screening the many derived mutations, and m…

p53 Immunotherapy of Cancer

Mutation and overexpression of the p53 tumor suppressor protein are the most common genetic alterations in human cancers. Peptides derived from non-mutated (wild type, wt) and mutated p53-molecules, processed and presented in the context of major histocompatibility complex (MHC) molecules by tumor cells for T-cell recognition, could serve as broad targets for cancer immunotherapy. Isolating p53-reactive T lymphocytes in healthy donors or patients has been hampered by the fact that most individuals display a peripheral p53-reactive T-cell repertoire that is devoid of high-avidity MHC class I-restricted cytotoxic T lymphocytes (CTL). Only low-avidity T lymphocytes are left due to self-toleran…

Impact of DLI after In Vivo T-Cell-Depletion: Prophylactic CD8 Depleted or Preemptive CD3pos DLI?

Abstract Introduction: The combination of reduced-intensity conditioning (RIC) with in vivo T-cell depletion by alemtuzumab prior to hematopoietic stem cell transplantation (HSCT) has demonstrated efficient engraftment and reduced graft-versus-host disease (GVHD). However, this regimen is associated with slow lymphocyte recovery leading to a delayed anti-infectious and anti-malignant immunity. DLI can be used to improve immune reconstitution. Here we investigate on the impact of different DLI: prophylactic CD8-depleted DLI vs preemptive non-depleted DLI. Methods: 256 patients with different hematologic malignancies were planned for treatment with DLI after allogeneic HSCT following reduced …

Designing TCR for Cancer Immunotherapy

Reprogramming T-cell populations by T-cell receptor (TCR) gene transfer is a new therapeutic tool for adoptive tumor immunotherapy. Gene transfer of human leukocyte antigen (HLA)-transgenic mice-derived TCR into human T-cells allows the circumvention of tolerance to tumor-associated (self) antigens (TAA). This chapter reports on the identification of the alpha and beta chains of the heterodimeric TCR derived from a mouse T-cell clone. The related DNA fragments are inserted into a retroviral vector for heterologous expression of the TAA-specific TCR in human T-cells. Polymerase chain reaction (PCR)-based cloning protocols are provided for the tailor-made customization of murine TCR. We descr…

p53 Isoform D133p53a: A Novel Transcriptional Enhancer of T-Cell Effector Function to Improve T-Cell Based Cancer Immunotherapy

Abstract Background: Adoptive transfer of genetically modified T lymphocytes with tumor antigen-specific receptor has proven efficacy in cancer immunotherapy. However, in many patients the overall benefit is still limited due to various tumor escape mechanisms. Cell damage and metabolic/hypoxic stress in the tumor microenvironment (TME) can lead to a dysfunctional anti-tumor T cell response called T cell senescence. The tumor suppressor TP53 is a master molecule in the regulation of cell cycle and senescence. Few studies have demonstrated the critical role of p53 isoforms in the regulation of cellular senescence mainly in tumor cells. However, their role in tumor infiltrating lymphocytes (T…

The sequence alteration associated with a mutational hotspot in p53 protects cells from lysis by cytotoxic T lymphocytes specific for a flanking peptide epitope.

A high proportion of tumors arise due to mutation of the p53 tumor suppressor protein. A p53 hotspot mutation at amino acid position 273 from R to H, flanking a peptide epitope that spans residues 264–272, renders cells resistant to killing by human histocompatibility leukocyte antigen (HLA)-A*0201–restricted cytotoxic T lymphocytes (CTLs) specific for this epitope. Acquisition of the R to H mutation at residue 273 of the human p53 protein promotes tumor growth in vivo by selective escape from recognition by p53.264–272 peptide-specific CTLs. Synthetic 27-mer p53 polypeptides covering the antigenic nonamer region 264–272 of p53 were used as proteasome substrates to investigate whether the R…

Adoptive Transfer of T-Cell-Receptor Engineered Human T Cells Specifically Reduces Viral Titers in HLA-Transgenic NSG Mice Infected with a Humanized Cytomegalovirus

Abstract Reactivation of latent human cytomegalovirus (HCMV) infection is a frequent complication in patients after allogeneic hematopoietic stem cell transplantation (HSCT). Preclinical research in murine models as well as clinical phase I/II trials have shown that the adoptive transfer of virus-specific CD8+ T cells is a therapeutic option for preventing HCMV disease. However, the feasibility of HCMV-specific immunotherapy is currently limited in clinical routine due to technical restrictions. It has also limitations, if the donor is HCMV-seronegative or carries only low numbers of HCMV-specific memory T cells. In this situation, grafting non-reactive T cells by virus-antigen specific T-c…

Nanoparticles and antigen-specific T-cell therapeutics: A comprehensive study on uptake and release

Aim: T lymphocytes are used as cellular therapeutics in many disease entities including cancer. We investigated the uptake and retention of nanoparticles (NPs) by these nonphagocytic cells. Materials &amp; methods: Uptake, release and toxicity of various polymeric NP preparations were analyzed by flow cytometry, confocal laser scanning microscopy and transmission electron microscopy. T-cell effector functions were measured using IFN-γ-ELISPOT and 51Chromium-release assays. Results: Amino-functionalized NPs were efficiently ingested by antigen-specific T cells without adversely influencing effector functions. NPs were stored in membrane-surrounded vesicles, with major proportions released e…

Erratum to: Cetuximab-induced skin exanthema: prophylactic and reactive skin therapy are equally effective

Purpose Treatment with cetuximab is accompanied by the development of an acneiform follicular skin exanthema in more than 80 % of patients. Severe exanthema (grade III/IV) develops in about 9–19 % of patients with the necessity of cetuximab dose reduction or cessation. Methods The study presented was a retrospective analysis of 50 gastrointestinal cancer patients treated with cetuximab in combination with either FOLFIRI or FOLFOX. One cohort of 15 patients received an in-house reactive skin protocol upon development of an exanthema. A second cohort of 15 patients received a skin prophylaxis starting with the first dose of cetuximab before clinical signs of toxicity. A third historic group o…

Sleeping Beauty transposon system – future trend in T-cell-based gene therapies?

Evaluation of: Huang X, Wilber AC, Bao L et al.: Stable gene transfer and expression in human primary T cells by the Sleeping Beauty transposon system. Blood 107, 483–491 (2006). The Sleeping Beauty (SB) transposon system can mediate stable gene transfer and expression in primary human T cells. Optimal in vitro conditions for maximum gene transfer efficiencies have been developed with regard to further application of the SB transposon system in T cell based gene therapies. This raises the question of whether or not the SB transposon system is a convincing alternative for virus-mediated gene transfer based on the currently available data. Here, we will discuss controversial safety and effic…

Analysis of the expression of SDF-1 splicing variants in human colorectal cancer and normal mucosa tissues

C-X-C motif chemokine ligand 12 (CXCL12), also termed stromal cell-derived factor-1 (SDF-1) is a small protein 8-14 kDa in length that is expressed as six isoforms, consisting of SDF-1α, SDF-1β, SDF-1γ, SDF-1δ, SDF-1ε and SDF-1θ. All six isoforms are encoded by the single CXCL12 gene on chromosome 10. This gene regulates leukocyte trafficking and is variably expressed in a number of normal and cancer tissues. The potential role of the novel CXCL12 splice variants as components of the CXCR4 axis in cancer development is not fully understood. The present study aimed to analyze the expression profile of the various SDF-1 isoforms and SDF-1 polymorphisms, and the association with the clinicopat…

Cytotoxicity of tumor antigen specific human T cells is unimpaired by arginine depletion.

Tumor-growth is often associated with the expansion of myeloid derived suppressor cells that lead to local or systemic arginine depletion via the enzyme arginase. It is generally assumed that this arginine deficiency induces a global shut-down of T cell activation with ensuing tumor immune escape. While the impact of arginine depletion on polyclonal T cell proliferation and cytokine secretion is well documented, its influence on chemotaxis, cytotoxicity and antigen specific activation of human T cells has not been demonstrated so far. We show here that chemotaxis and early calcium signaling of human T cells are unimpaired in the absence of arginine. We then analyzed CD8(+) T cell activation…

Patient-individualized CD8+cytolytic T-cell therapy effectively combats minimal residual leukemia in immunodeficient mice

Adoptive transfer of donor-derived cytolytic T-lymphocytes (CTL) has evolved as a promising strategy to improve graft-versus-leukemia (GvL) effects in allogeneic hematopoietic stem-cell transplantation. However, durable clinical responses are often hampered by limited capability of transferred T cells to establish effective and sustained antitumor immunity in vivo. We therefore analyzed GvL responses of acute myeloid leukemia (AML)-reactive CD8(+) CTL with central and effector memory phenotype in a new allogeneic donor-patient specific humanized mouse model. CTL lines and clones obtained upon stimulation of naive CD45RA(+) donor CD8(+) T cells with either single HLA antigen-mismatched or HL…

Effect of priming ith granulocyte-colony-stimulating factor on the outcome of chemotherapy for acute myeloid leukemia

BACKGROUND: Sensitization of leukemic cells with hematopoietic growth factors may enhance the cytotoxicity of chemotherapy in acute myeloid leukemia (AML). METHODS: In a multicenter randomized trial, we assigned patients (age range, 18 to 60 years) with newly diagnosed AML to receive cytarabine plus idarubicin (cycle 1) and cytarabine plus amsacrin (cycle 2) with granulocyte colony-stimulating factor (G-CSF) (321 patients) or without G-CSF (319). G-CSF was given concurrently with chemotherapy only. Idarubicin and amsacrin were given at the end of a cycle to allow the cell-cycle-dependent cytotoxicity of cytarabine in the context of G-CSF to have a greater effect. The effect of G-CSF on dise…

Δ133p53α enhances metabolic and cellular fitness of TCR-engineered T cells and promotes superior antitumor immunity

BackgroundTumor microenvironment-associated T cell senescence is a key limiting factor for durable effective cancer immunotherapy. A few studies have demonstrated the critical role of the tumor suppressor TP53-derived p53 isoforms in cellular senescence process of non-immune cells. However, their role in lymphocytes, in particular tumor-antigen (TA) specific T cells remain largely unexplored.MethodsHuman T cells from peripheral blood were retrovirally engineered to coexpress a TA-specific T cell receptor and the Δ133p53α-isoform, and characterized for their cellular phenotype, metabolic profile and effector functions.ResultsPhenotypic analysis of Δ133p53α-modified T cells revealed a marked …

Xenograft models for undifferentiated pleomorphic sarcoma not otherwise specified are essential for preclinical testing of therapeutic agents

Undifferentiated pleomorphic sarcoma not otherwise specified belongs to the heterogeneous group of soft tissue tumors. It is preferentially located in the upper and lower extremities of the body, and surgical resection remains the only curative treatment. Preclinical animal models are crucial to improve the development of novel chemotherapeutic agents for the treatment of undifferentiated pleomorphic sarcoma. However, this approach has been hampered by the lack of reproducible animal models. The present study established two xenograft animal models generated from stable non-clonal cell cultures, and investigated the difference in chemotherapeutic effects on tumor growth between undifferenti…

Circumventing tolerance to a human MDM2-derived tumor antigen by TCR gene transfer

We identified a tumor-associated cytotoxic T lymphocyte (CTL) epitope derived from the widely expressed human MDM2 oncoprotein and were able to bypass self-tolerance to this tumor antigen in HLA-A*0201 (A2.1) transgenic mice and by generating A2.1-negative, allo-A2.1-restricted human T lymphocytes. A broad range of malignant, as opposed to nontransformed cells, were killed by high-avidity transgenic mouse and allogeneic human CTLs specific for the A2.1-presented MDM2 epitope. Whereas the self-A2.1-restricted human T cell repertoire gave rise only to low-avidity CTLs unable to recognize the natural MDM2 peptide, human A2.1+ T lymphocytes were turned into efficient MDM2-specific CTLs upon exp…

Outcomes of Mismatched Related Allogeneic Stem Cell Transplantation for Chronic Lymphocytic Leukemia: A Retrospective Study on Behalf of the Chronic Malignancies Working Party of the EBMT

Abstract Introduction: Allogeneic hematopoietic stem cell transplantation (HCT) is a treatment for CLL that can give long disease control. Even with the availability of kinase and BCL2 inhibitors, HCT is still performed in fit patients (pts) with high-risk CLL. Almost exclusively, outcomes on matched related and unrelated donor transplantations in CLL have been published. Recently, mismatched related donors are gaining interest because of the better outcome of haploidentical HCT with post-transplantation cyclophosphamide (PTCY). Methods: All pts with CLL who received a first allogeneic HCT with a mismatched related donor and whose data were available in the EBMT registry were analyzed. Medi…

Synergistic targeting of FLT3 mutations in AML via combined menin-MLL and FLT3 inhibition

Abstract The interaction of menin (MEN1) and MLL (MLL1, KMT2A) is a dependency and provides a potential opportunity for treatment of NPM1-mutant (NPM1mut) and MLL-rearranged (MLL-r) leukemias. Concomitant activating driver mutations in the gene encoding the tyrosine kinase FLT3 occur in both leukemias and are particularly common in the NPM1mut subtype. In this study, transcriptional profiling after pharmacological inhibition of the menin-MLL complex revealed specific changes in gene expression, with downregulation of the MEIS1 transcription factor and its transcriptional target gene FLT3 being the most pronounced. Combining menin-MLL inhibition with specific small-molecule kinase inhibitors…

Nitric Oxide Promotes Resistance to Tumor Suppression by CTLs

Abstract Many human tumors express inducible NO synthetase (NOS2), but the roles of NO in tumor development are not fully elucidated. An important step during tumor development is the acquisition of apoptosis resistance. We investigated the dose-dependent effects of endogenously produced NO on apoptosis using ecdysone-inducible NOS2 cell lines. Our results show that short-term NOS2 expression enhances CD95-mediated apoptosis and T cell cytotoxicity dose dependently. Furthermore, we could show that during chronic exposure to NO, besides the primary cytotoxic NO effect, there is selection of cell clones resistant to NO that show cross-resistance to CD95-induced apoptosis and the killing by CT…

Impact of Donor Type on Outcome after Allogeneic Stem Cell Transplantation in Acute Myeloid Leukemia Patients: Analysis of the German-Austrian Acute Myeloid Leukemia Study Group (AMLSG)

Abstract Background:Despite recent advances in identifying novel molecular targets in AML patients, intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation (HSCT) still remains a cornerstone of AML therapy. However, outcome of HSCT depends on the availability of a donor and the donor type. Prior studies comparing HSCT from HLA-matched related donors (MRD) with matched unrelated donors (MUD), demonstrated conflicting results with regards to outcome. These conflicting results might be attributed to the genetic heterogeneity of AML. Aims:To analyze outcome with respect to donor type of 952 AML patients who received HSCT in first complete remission (CR) and were tr…

The Impact of NFAT Inhibition on Neutrophil Antifungal Defense and Myelopoiesis in Cyclosporine A Treated and NFATc1LysM Mice

Abstract Background and Aims: Immunodeficient patients after allogeneic stem cell transplantation (HSCT) are heavily threatened by opportunistic fungal infections like invasive pulmonary aspergillosis (IPA), partly due to immunosuppressive medication e.g. by calcineurin inhibitors like cyclosporine A (CsA) or tacrolimus. It is well known that the nuclear factor of activated T cells (NFAT) is an important transcription factor downstream of calcineurin in the adaptive immune system especially in T cells. Additionally, there is a growing body of evidence that NFAT also plays a substantial role in innate immune response against invasive fungal diseases by polymorphonuclear neutrophils (PMN), as…

Combined Targeting of the Menin-MLL1 Chromatin Complex and FLT3 As a Novel Therapeutic Concept Against NPM1 Mutant or MLL-Rearranged AML with Mutated FLT3

NPM1mutant (NPM1mut) and MLL1-rearranged (MLL-r) acute myeloid leukemias (AMLs) exhibit aberrant expression of HOX and MEIS1 transcription factors and commonly harbor an activating mutation in the receptor tyrosine kinase FLT3. Pharmacologic inhibition of the menin-MLL1 complex reverses leukemogenic gene expression including MEIS1 and FLT3 and represents a therapeutic opportunity for the treatment of these leukemias. Here, we investigate the contribution of the menin-MLL1 complex to leukemic FLT3 signaling and assess the therapeutic potential of dual menin-MLL1 and FLT3 targeting. First, we performed RNA sequencing to delineate transcriptional changes associated with menin-MLL1 inhibition (…

Targeting Aberrant Ncam (neural cell adhesion molecule; CD56) Expression in Acute Myeloid Leukemia

Abstract Background Acute myeloid leukemia (AML) is a heterogeneous disease of the hematopoietic progenitor cell driven by the subsequent acquisition of genetic alterations. Approximately 20% of AML patients show strong expression of CD56 (neural cell adhesion molecule; NCAM). Expression of NCAM is associated with poor overall survival; however, the functional role of aberrant NCAM expression has not been investigated to date. The goal of this study is to examine the biological role of NCAM in AML and to explore whether NCAM represents a potential therapeutic target. Results In order to evaluate the clinical significance of elevated NCAM expression in AML, we screened a panel of human cell …

Cooperation of Human Tumor-Reactive CD4+ and CD8+ T Cells after Redirection of Their Specificity by a High-Affinity p53A2.1-Specific TCR

Abstract Efficient immune attack of malignant disease requires the concerted action of both CD8 + CTL and CD4 + Th cells. We used human leukocyte antigen (HLA)-A*0201 (A2.1) transgenic mice, in which the mouse CD8 molecule cannot efficiently interact with the α3 domain of A2.1, to generate a high-affinity, CD8-independent T cell receptor (TCR) specific for a commonly expressed, tumor-associated cytotoxic T lymphocyte (CTL) epitope derived from the human p53 tumor suppressor protein. Retroviral expression of this CD8-independent, p53-specific TCR into human T cells imparted the CD8 + T lymphocytes with broad tumor-specific CTL activity and turned CD4 + T cells into potent tumor-reactive, p53…

Final Results of a Phase I/II Trial of the Combination Bendamustine and Rituximab With Temsirolimus (BeRT) in Relapsed Mantle Cell Lymphoma and Follicular Lymphoma

Abstract. In this phase I/II study, we explored the combination of Temsirolimus with Bendamustine and Rituximab (BeRT) in patients with relapsed or refractory (r/r) follicular lymphoma (FL) or mantle cell lymphoma (MCL). Patients with 1 to 3 previous therapies received Bendamustine (90 mg/m2, day 1 + 2) and Rituximab (375 mg/m2, day 1) with Temsirolimus in doses from 25 to 75 mg in phase I and 50 mg Temsirolimus in phase II, added on day 1, 8, 15 of a 28 days cycle. The primary endpoint of the phase II was ORR at the end of treatment. Overall, 39 (29 MCL, 10 FL) patients were included. Median age was 71 years and median pretreatment number was 2. Grade 3/4 non-hematologic adverse events wer…

Safe and Effective Adoptive T-Cell Receptor Transfer with a High Affinity Single Chain p53(264–272)-Specific TCR

Abstract Abstract 4226 Several studies have demonstrated the clinical efficacy of adoptive T cell therapy for targeting cancer. Using HLA-A2.1 transgenic mice, we have demonstrated the feasibility of T-cell receptor (TCR) gene transfer into T cells to circumvent self-tolerance to the widely expressed human p53(264–272) tumor-associated antigen and developed approaches to generate high-affinity CD8-independent TCR. A safety concern of TCR gene transfer is the pairing of endogenous and introduced TCR chains resulting in the potential generation of self-reactive T cells (off-target autoimmunity). Several strategies to favor matched TCR chains pairing and thus enhancing TCR cell surface express…

Neuroendocrine Regulation Of The IL-27-Dependent Immune Response In Macrophages

Abstract The central nervous system has the ability for modulating immune responses, but the molecular mechanisms of such interactions are only partly understood. Interleukin-27 (IL-27) is a heterodimeric protein and structurally related to the IL-12 family of cytokines. IL-27 is composed of the subunits EBI3 and p28. The biological functions of IL-27 have been described as either anti-inflammatory or pro-inflammatory depending on the experimental models studied. In the current study, we investigated how production of Interleukin-27 (IL-27) is regulated by neuroendocrine hormones. We focused our work on the subunit p28, since EBI3 is also present in IL-35 and therefore is not a specific com…

COVID-19 as a Potential Trigger for Immune Thrombotic Thrombocytopenic Purpura and Reason for an Unusual Treatment: A Case Report

AbstractImmune thrombotic thrombocytopenic purpura (iTTP) is a rare autoimmune disorder characterized by severely reduced activity of the von Willebrand factor (VWF)-cleaving protease ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) due to autoantibodies. This leads to the development of pathogenic multimers of VWF, causing a thrombotic microangiopathy with decreased number of platelets, hemolysis, and life-threatening tissue ischemia of mostly brain, heart, and kidneys. Standard treatment of iTTP involves daily plasma exchange to remove ultra large multimers of VWF, inhibitors, substituting ADAMTS13, and the accompaniment of an immunosuppressive …

Vaccination with WT1 and PR3 Derived Peptides in Patients with AML/MDS and MUC1 Peptides in Patients with Multiple Myeloma - Preliminary Results.

Abstract Background: It has been demonstrated that the Wilms Tumor gene (WT1) is highly expressed in various types of leukaemia. WT1 expression level reflects the extent of minimal residual disease and significantly increases at relapse. Proteinase 3 (Pr3) is an aberrantly expressed myeloid leukaemia protein and T cells with specificity for both, Wt1 and Pr3 derived antigens, have been generated in vitro from healthy individuals and cancer patients and lysed myeloid leukaemic blasts. MUC1(CD227) is presented on a considerable amount of multiple myeloma cell lines and plasmocytoma cells. MUC1-derived HLA-class I/II epitopes represent universal tumor antigens, which are also expressed by mali…

Playing the Game Together: Coexpression of a Single Chain T Cell Receptor and a T Cell Receptor Constant-Alpha Domain Triggers Tumor Reactivity.

Abstract Grafting T cells by tumor-antigen specific T cell receptors (TCR) could trigger the initiation of effector function and redirect T cell cytotoxicity towards tumors. We utilized various HLA-A2.1 transgenic mice to bypass human MDM2- and p53-specific self-tolerance. In contrast to the use of HuCD8×A2Kb transgenic mice to generate an MDM2-specific CD8-dependent TCR, we generated a high-affinity, CD8-independent p53-specific TCR in single human A2.1 transgenic mice. The efficiency of double chain (dc) TCR modified T cells could be affected by the incorrect TCR α/β chain pairing between endogenous and transgenic TCR constructs to form hybrid TCR potentially leading to autoimmunity. To a…

Transcutaneous Immunization with a Solid Nanoscopic Imiquimod Suspension Enhances Tumor Rejection

Abstract Introduction: Transcutaneous immunization (TCI) is a novel vaccination strategy to induce strong therapeutic cytotoxic T-lymphocyte (CTL) responses by directly targeting skin-resident professional antigen-presenting cells (APC). This vaccination approach is very promising to overcome current limitations of standard vaccination approaches that are mostly effective in prophylaxis, but not in the treatment of diseases. In this context, we have developed a TCI method based on a synthetic TLR7 agonist imiquimod that partial tumor protection in experimental rodent models. In our present work, we describe a novel optimized formulation of imiquimod in a solid suspension of crystalline imiq…

Follow Up On CD8-Depleted Donor-Lymphocyte Infusions After T-Cell Depleted Allogeneic Hemopoietic Stem Cell Transplantation

We applied prophylactic CD8-depleted (CD8depl) donor lymphocyte infusions (DLI) in the setting of T-cell depleted reduced-intensity allogeneic hematopoietic stem cell transplantation (HSCT) in a phase I/II trial. T-cell depletion was carried out by the use of high-dose Alemtuzumab (100 mg or 60 mg for unrelated or sibling donor transplantation, respectively). We have demonstrated the feasibility of this approach after having treated 23 patients in this protocol (Meyer et al. Blood 2007). From 2004 to 2011, 134 patients with different hematologic diseases were included and followed for a median observation time of 1.5 years after transplantation (range, 1.5-9 years). Median age was 56 years …

Human Epidermal Langerhans Cells Replenish Skin Xenografts and Are Depleted by Alloreactive T Cells In Vivo

Abstract Epidermal Langerhans cells (LC) are potent APCs surveying the skin. They are crucial regulators of T cell activation in the context of inflammatory skin disease and graft-versus-host disease (GVHD). In contrast to other dendritic cell subtypes, murine LC are able to reconstitute after local depletion without the need of peripheral blood-derived precursors. In this study, we introduce an experimental model of human skin grafted to NOD-SCID IL2Rγnull mice. In this model, we demonstrate that xenografting leads to the transient loss of LC from the human skin grafts. Despite the lack of a human hematopoietic system, human LC repopulated the xenografts 6 to 9 wk after transplantation. By…

Targeting Acute Leukemia and Cancer by High-Affinity T-Cell-Receptor Transfer

Accumulation and subsequent overexpression of human mdm2 (hdm2) and altered p53 protein is associated with high-level presentation of hdm2 and wild-type (wt) p53 derived peptides by major histocompatibility complex (MHC) class I molecules on a wide range of malignant cells. A major barrier to the design of broad-spectrum hdm2 and p53 specific immunotherapeutics for leukemia and cancer, however, has been the observation that low-level expression of hdm2 and wt p53 peptides by non-transformed tissues and cells results in self-tolerance of T-lymphocytes with high avidity for self-class I MHC / self-peptide complexes. Although the peripheral T-cell repertoire is mostly devoid of such high-avidi…

Generating p53-specific cytotoxic T lymphocytes by recombinant adenoviral vector-based vaccination in mice, but not man.

Mutations and aberrant expression of the p53 tumor suppressor protein are the most frequent molecular alterations in human malignancy. Peptides derived from the wild-type (wt) p53 protein and presented by major histocompatibility complex (MHC) molecules for T lymphocyte recognition are believed to serve as universal tumor-associated antigens for cancer immunotherapy. We studied the immunogeneicity of a recombinant replication-defective adenoviral vector encoding human full-length wt p53 (rAd/hup53) in human leukocyte antigen (HLA)-A2K(b)-transgenic (Tg) mice and man. The generation of p53 epitope-specific cytotoxic T lymphocytes (CTLs) in p53-proficient and p53-deficient A2K(b)-Tg mice was …

CD11b Regulates Fungal Outgrowth but Not Neutrophil Recruitment in a Mouse Model of Invasive Pulmonary Aspergillosis

Abstract Background and Aims: In immunosuppressed individuals Aspergillus (A.) fumigatus is a frequent cause of invasive pulmonary aspergillosis (IPA) which is highly associated with relevant morbidity and mortality. Moreover, it often occurs in patients suffering from leukocyte-adhesion deficiency type 1 (LAD1) which is triggered by a functional loss of CD18 in ß2 integrin receptors as these receptors consist of an alpha subunit (CD11a-CD11d) and CD18 as the common beta subunit. ß2 integrin receptors are differentially expressed by leukocytes, and are required for cell-cell interaction, transendothelial migration, uptake of opsonized pathogens, and cell signaling processes. Here, we asked …

Processing and MHC class I presentation of human cytomegalovirus pp65-derived peptides persist despite gpUS2–11-mediated immune evasion

Immune control of human cytomegalovirus (HCMV) infection can be mediated by CD8+cytolytic T lymphocytes (CTL). Adoptive transfer of antiviral CTL confers protection against HCMV reactivation and disease. The tegument protein pp65 and the immediate-early 1 protein (IE1) are recognized to be major CTL targets, even though during productive infection the viral immunoevasion proteins gpUS2–11 act to suppress major histocompatibility complex (MHC) class I-restricted antigen presentation. Thus it was not clear how infected cells could be labelled with antigenic peptides in the face of immunoevasion. We show here that the immunodominant peptide pp65NLVwas presented by MHC class I in cells infected…

An immune escape screen reveals Cdc42 as regulator of cancer susceptibility to lymphocyte-mediated tumor suppression.

Abstract Adoptive cellular immunotherapy inducing a graft-versus-tumor (GVT) effect is the therapeutic mainstay of allogeneic hematopoietic stem cell transplantation (ASCT) for high-risk leukemias. Autologous immunotherapies using vaccines or adoptive transfer of ex vivo–manipulated lymphocytes are clinically explored in patients with various cancer entities. Main reason for failure of ASCT and cancer immunotherapy is progression of the underlying malignancy, which is more prevalent in patients with advanced disease. Elucidating the molecular mechanisms contributing to immune escape will help to develop strategies for the improvement of immunologic cancer treatment. To this end, we have und…

Efficacy and safety of imatinib in adult patients with c-kit–positive acute myeloid leukemia

Abstract This phase 2 pilot study was conducted to determine the efficacy and safety of imatinib mesylate in patients with c-kit–positive acute myeloid leukemia (AML) refractory to or not eligible for chemotherapy. Twenty-one patients were enrolled and received imatinib 600 mg orally once daily. Five responses were seen primarily in patients, starting with relatively low blast counts in bone marrow (BM) and peripheral blood (PB): 2 patients who were considered refractory on chemotherapy on the basis of persistence of blasts in PB and BM met the criteria for complete hematologic remission, 1 patient had no evidence of leukemia, and 2 patients achieved a minor response. Treatment with imatini…

Evaluating Human T-Cell Therapy of Cytomegalovirus Organ Disease in HLA-Transgenic Mice

Reactivation of human cytomegalovirus (HCMV) can cause severe disease in recipients of hematopoietic stem cell transplantation. Although preclinical research in murine models as well as clinical trials have provided 'proof of concept' for infection control by pre-emptive CD8 T-cell immunotherapy, there exists no predictive model to experimentally evaluate parameters that determine antiviral efficacy of human T cells in terms of virus control in functional organs, prevention of organ disease, and host survival benefit. We here introduce a novel mouse model for testing HCMV epitope-specific human T cells. The HCMV UL83/pp65-derived NLV-peptide was presented by transgenic HLA-A2.1 in the conte…

Protein�A immunoadsorption therapy for refractory, mitomycin�C?associated thrombotic microangiopathy

BACKGROUND: Mitomycin C–associated thrombotic microangiopathy (TMA) has a poor prognosis with limited therapeutic options. Most patients die within 4 months of diagnosis due to pulmonary or renal failure. Here, a patient resistant to total plasma exchange (TPE) and immunosuppressive therapy with glucocorticoids, rituximab, vincristine, and splenectomy who was successfully treated with protein A immunoadsorption is described. CASE REPORT: A 29-year-old woman developed a TMA after chemotherapy with mitomycin C. She presented with thrombocytopenia, pulmonary edema, hemolytic anemia with presence of schistocytes, and renal failure. Immediate TPE (>120 times) and immunosuppressive therapy with g…

The Programmed Death (PD)‐1/PD‐Ligand 1 Pathway Regulates Graft‐Versus‐Host‐Reactive CD8 T Cells After Liver Transplantation

Acute graft-versus-host disease (aGVHD) is a life-threatening complication after solid-organ transplantation, which is mediated by host-reactive donor T cells emigrating from the allograft. We report on two liver transplant recipients who developed an almost complete donor chimerism in peripheral blood and bone marrow-infiltrating T cells during aGVHD. By analyzing these T cells directly ex vivo, we found that they died by apoptosis over time without evidence of rejection by host T cells. The host-versus-donor reactivity was selectively impaired, as anti-third-party and antiviral T cells were still detectable in the host repertoire. These findings support the acquired donor-specific allotol…

Strategies for tumor elimination by cytotoxic T lymphocytes.

Despite differences in their tissue of origin, many tumors share high level expression of certain tumor-associated proteins. Our laboratory has focused on the possibility of utilizing antigenic components of these proteins as a focus for T-cell immunotherapy of cancer. The advantage of targeting such commonly expressed proteins is the fact that such therapy could be of value in eliminating many different types of tumors. A potential barrier in the identification of T-cell epitopes derived from these proteins and presented by tumor cells is the fact that these proteins are also expressed at low levels in some normal tissues, and therefore, self-tolerance may eliminate T cells that are capabl…

Comparison of Allogeneic Stem Cell Transplantation for Transformed Acute Myeloid Leukemia Derived from MDS, CMML or MPN. a Report of the Chronic Malignancies Working Party of EBMT

Abstract Introduction Myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN) and chronic myelomonocytic leukemia (CMML) can progress to acute myeloid leukemia (transformed AML). The aim of this EBMT registry study was to compare 3 year outcome in patients with transformed AMLwho received allogeneic stem cell transplantation according to the primary disease. Patients and Methods Within the European Society of Blood and Marrow Transplantation (EBMT) registry, we found 4214 patients (female: 39%, male: 61%) with transformed acute myeloid leukemia, who received allogeneic stem cell transplantation between 2000 and 2014. The primary disease was MDS (n=3541), CMML (n=251) or MPN (n=4…

Cytomegalovirus Interleukin-10 Expression in Infected Cells Does Not Impair MHC Class I Restricted Peptide Presentation on Bystanding Antigen-Presenting Cells

Human cytomegalovirus (HCMV) has evolved strategies to counteract its surveillance by the immune system. Mitigation of antiviral immune responses is considered critical for establishment of viral latency and for spread. Recently, a gene encoding an interleukin-10 homologue (cmvIL-10) has been discovered in the HCMV genome. Using recombinant cmvIL-10, several mostly immunosuppressive functions of the molecule have been described. However, the role of cmvIL-10 in the context of viral infection was not addressed. To be able to analyze this issue, we generated cmvIL- 10-negative viral mutants. Using these mutants, we tested whether the expression of cmvIL-10 by infected cells would render bysta…

Impact of Prophylactic CD8-Depleted Donor-Lymphocyte Infusions After Allogeneic Hematopoietic Stem Cell Transplantation and Alemtuzumab Mediated T-Cell Depletion,

Abstract Abstract 4109 We have previously demonstrated that the application of CD8-depleted donor-lymphocyte infusions (DLI) is feasible after reduced-intensity conditioning and in vivo T-cell depletion by alemtuzumab. DLI overcome slow lymphocyte recovery associated with alemtuzumab-administration and improve anti-infectious immunity and reliably convert a decreasing T-cell chimerism (Meyer et al. Blood 2007 &amp; BMT 2010). Here we provide clinical follow up data of 117 patients with different hematological diseases and a median observation time of 1 year (range, 1–86 months) post hematopoietic stem cell transplantation (HSCT). The majority of patients either suffered from an acute leukem…

Gentherapeutischer T-Zell-Rezeptor-Transfer

Interfering with Arginine Metabolism As a New Treatment Strategy for Multiple Myeloma

Abstract Introduction Starvation of tumor cells from the amino acid arginine has recently gained particular interest because of the downregulation of the rate-limiting enzyme argininosuccinate synthethase 1 (ASS1) in various cancer entities. ASS1-deficient cells cannot resynthesize arginine from citrulline and are therefore considered arginine auxotrophic. The arginine depleting enzyme arginine deiminase (ADI-PEG20, Polaris Pharmaceuticals) is currently tested in phase I-III clinical trials for different arginine auxotrophic cancers. The natural arginine analogue canavanine can compete with arginine for arginyl-tRNA-binding sites and consequently be incorporated into nascent proteins instea…

Obinutuzumab (GA101) in Combination with Pixantrone for the Treatment of Patients with Relapsed Aggressive B-Cell Lymphoma: Report on an Ongoing Phase II Trial (GOAL)

Abstract Background: Prognosis of diffuse large B-cell lymphoma (DLBCL) and other aggressive lymphoma entities has improved with the advent of Rituximab, and R-CHOP-21 and variants is SOC. Nevertheless, a substantial proportion of patients fail first line treatment. Salvage therapies are often effective. However, no more than 25-50% achieve a long term remission even when consolidative high dose chemotherapy (HDT) followed by hematopoietic stem cell transplantation (SCT) is applied. In case of failure or intolerance to HDT, regimen like Gemcitabine/Oxaliplatin are applied but show limited efficacy, indicating the need for new treatments. Obinutuzumab (GA101) is a type II anti-CD20 antibody.…

Redirection of T cells by delivering a transgenic mouse-derived MDM2 tumor antigen-specific TCR and its humanized derivative is governed by the CD8 coreceptor and affects natural human TCR expression.

Retroviral transfer of T cell antigen receptor (TCR) genes selected by circumventing tolerance to broad tumor- and leukemia-associated antigens in human leukocyte antigen (HLA)-A*0201 (A2.1) transgenic (Tg) mice allows the therapeutic reprogramming of human T lymphocytes. Using a human CD8 x A2.1/Kb mouse derived TCR specific for natural peptide-A2.1 (pA2.1) complexes comprising residues 81-88 of the human homolog of the murine double-minute 2 oncoprotein, MDM2(81-88), we found that the heterodimeric CD8 alpha beta coreceptor, but not normally expressed homodimeric CD8 alpha alpha, is required for tetramer binding and functional redirection of TCR- transduced human T cells. CD8+T cells that…

Cetuximab-induced skin exanthema: prophylactic and reactive skin therapy are equally effective

Purpose Treatment with cetuximab is accompanied by the development of an acneiform follicular skin exanthema in more than 80 % of patients. Severe exanthema (grade III/IV) develops in about 9–19 % of patients with the necessity of cetuximab dose reduction or cessation.

Depletion of naive T cells using clinical grade magnetic CD45RA beads: a new approach for GVHD prophylaxis

Depletion of naive T cells from donor leukapheresis products (LPs) aims at the reduction of alloreactivity, while preserving memory T-cell reactivity (for example, to pathogens). This study established the immunomagnetic depletion procedure under clean room conditions using CD45RA beads and analyzed LPs of six donors for cell composition and functional immune responses. CD45RA depletion resulted in 3.4-4.7 log (median 4.4) reduction of CD45RA(+) T cells, thereby eliminating naive and late effector T cells. B cells were also completely removed, whereas significant proportions of NK cells, monocytes and granulocytes persisted. CD45RA-depleted LPs contained effector and central memory CD4(+) a…

Redirected EBV-Specific Stem Cell-Memory and Central-Memory CD8+ T Lymphocytes Exhibit Effective and Sustained Antileukemic Immunity to Acute Myeloid Leukemia in a Patient-Tailored Humanized NSG Mouse Model

Abstract Introduction: Adoptive cellular therapy (ACT) of donor-derived cytolytic T lymphocytes (CTL) directed to leukemia or herpesvirus has proven promising to improve antiviral and antileukemic immunity in patients following allogeneic hematopoietic stem cell transplantation (AHSCT). However, durable clinical responses are often hampered by detrimental graft-versus host (GvH) reactivity and limited persistence of transferred, fully differentiated antileukemic effector T cells (TEFF). We thus explored memory and tumoricidal features of in vitro generated EBV-specific stem cell-memory T cells (TSCM) and central-memory T (TCM) cells, T cell-receptor (TCR) redirected to primary acute myeloid…

Immune Therapy of Lympho-Hemopoietic Malignancies.

Treatment Results In Acute Myeloid Leukemia Over a Time Period Of 20 Years: Analysis Of The German-Austrian Acute Myeloid Leukemia Study Group (AMLSG)

Abstract Background Overall survival (OS) in acute myeloid leukemia (AML) treated with intensive chemotherapy has improved over the last 20 year especially in younger adults (18-60 years) but still remains poor in older patients (&gt;60 years) (Döhner et al. Blood 2010). The German-Austrian AMLSG performed controlled prospective treatment trials since 1993 starting with a risk-adapted approach (phase I, 1993-1997), followed by randomized and risk-adapted treatment strategies based on cytogenetic risk groups (phase II, 1997-2002); since 2003 addition of differentiating agents and HiDAC inhibitors to intensive induction therapy was evaluated (phase III, 2003-2007). Of note, until 2007 younger…

Ibrutinib Abrogates TREM-1 Mediated Neutrophil Activation

Abstract Triggering receptor expressed on myeloid cells 1 (TREM-1) is an activating receptor on neutrophils (PMN) and important in the innate host defence against microbial pathogens. Here we examined the influence of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib on TREM-1 dependent activation of human PMNs. Firstly, ibrutinib specifically inhibited TREM-1 mediated PMN activation of the oxidative burst and CD62L shedding, whereas TLR mediated activation remained unaffected. Correspondingly, ibrutinib suppressed ERK phosphorylation after TREM-1, but not after TLR ligation. To clarify whether this TREM-1 specific effect of ibrutinib was also relevant in vivo, we treated mice with ibrut…

Inhibition of Arginase 1 Liberates Potent T Cell Immunostimulatory Activity of Human Neutrophil Granulocytes

Myeloid cell arginase-mediated arginine depletion with consecutive inhibition of T cell functions is a key component of tumor immune escape. Both, granulocytic myeloid-derived suppressor cells (G-MDSC) and conventional mature human polymorphonuclear neutrophil granulocytes (PMN) express high levels of arginase 1 and can act as suppressor cells of adaptive anti-cancer immunity. Here we demonstrate that pharmacological inhibition of PMN-derived arginase 1 not only prevents the suppression of T cell functions but rather leads to a strong hyperactivation of T cells. Human PMN were incubated in cell culture medium in the absence or presence of an arginase inhibitor. T cells from healthy donors w…

Safety of the Anti-CD19 antibody Tafasitamab in Long Term Responders from A Phase II Trial for Relapsed Lymphoma

Abstract Background: Information about the long-term tolerability of tafasitamab is still limited. Methods: 5 of 92 patients treated within a phase IIa study of single-agent tafasitamab in relapsed or refractory B NHL were followed for up to five years or longer for long-term tolerability. Results: Treatment was very well tolerated in an outpatient setting with no hospitalizations needed and mild and tolerable adverse events that occurred mostly within the first two years of treatment. Conclusions: Given the excellent tolerability and efficacy of tafasitamab this agent can be used to induce remission in relapsed or refractory lymphoma either alone or in combination with chemotherapy.

Reconstructing an Anti-Tumor Immune Repertoire for Targeted AML Therapy

A bicistronic vector backbone for rapid seamless cloning and chimerization of αβT-cell receptor sequences.

To facilitate preclinical testing of T-cell receptors (TCRs) derived from tumor-reactive T-cell clones it is necessary to develop convenient and rapid cloning strategies for the generation of TCR expression constructs. Herein, we describe a pDONR™221 vector backbone allowing to generate Gateway™ compatible entry clones encoding optimized bicistronic αβTCR constructs. It harbors P2A-linked TCR constant regions and head-to-head-oriented recognition sites of the Type IIS restriction enzymes BsmBI and BsaI for seamless cloning of the TCRα and TCRβ V(D)J regions, respectively. Additional well-established TCR optimizations were incorporated to enhance TCR functionality. This included replacing of…

Treatment-Induced Aggravation of Vasculitis in Hairy-Cell Leukemia

The effect of the interferon-γ-inducible processing machinery on the generation of a naturally tumor-associated human cytotoxic T lymphocyte epitope within a wild-type and mutant p53 sequence context

The human wild-type (wt) p53.264–272 peptide is a universal tumor antigen and recognized by HLA-A*0201 (A2.1)-restricted CTL. Generation of this epitope by constitutive 20S proteasomes is prevented by a p53 R to H hotspot mutation at the C-terminal flanking residue 273. We report on the impact of the interferon-γ (IFN-γ)-inducible proteasomal activator PA28 (11S regulator) and the immunoproteasome on the in vitro and cellular processing of wt and mutant (mut) p53 substrates. We found that production of the antigenic 264–272 peptide from wt p53 by constitutive as well as immunoproteasomes is accelerated and amplified by the PA28 activator. PA28 and (immuno)proteasomes were not capable to rec…

CD52‐negative T cells predict acute graft‐versus‐host disease after an alemtuzumab‐based conditioning regimen

Allogeneic haematopoietic stem cell transplantation (HSCT) after a reduced-intensity conditioning (RIC) regimen with fludarabine, melphalan and alemtuzmab is an effective therapy for haematological malignancies. Alemtuzumab, a monoclonal antibody against CD52, a glycosylphosphatidylinositol-anchor-bound surface protein on lymphocytes, depletes T cells to prevent graft-versus-host disease (GVHD). Despite this, acute and chronic GVHD (a/cGVHD) remain life-threatening complications after HSCT. The aim of the present study was to identify parameters to predict GVHD. In 69 patients after HSCT, T-cell subsets were functionally analysed. Reconstitution of CD52neg T cells and CD52neg regulatory T c…

EGF and HGF levels are increased during active HBV infection and enhance survival signaling through extracellular matrix interactions in primary human hepatocytes

The hepatitis B virus (HBV) is a major causative agent of chronic liver disease and subsequent liver cirrhosis worldwide. The reduced sensitivity of virus-infected liver cells to apoptosis may play a role in the failure to remove virus-infected cells and eventually promote viral chronicity. The purpose of our study was to investigate whether survival factors induced during compensatory liver regeneration may protect hepatocytes against apoptosis. We evaluated the serum levels of hepatocyte growth factor (HGF) and epidermal growth factor (EGF) in HBV-infected patients and found significant increases in HGF and EGF in patients with active virus infection. In primary human hepatocytes we show …

All-Trans Retinoic Acid and Gemtuzumab Ozogamicin as Adjunct To Salvage Therapy in Primary Refractory Acute Myeloid Leukemia: Results of Consecutive Phase II Studies of the AMLSG.

Abstract Introduction: Response to first induction therapy is one of the most important prognostic factors in patients with adult myeloid leukemia (AML). Induction of CR or PR is the primary aim in these patients. Methods: Between 1993 and 2005 225 consecutive patients (median age: 48.4 yrs, range 16–60 yrs) treated within the AMLHD93 (n=45), AMLHD98A (n=157) and AMLSG 05-04 (n=23, still active) trials were evaluated. All patients had primary refractory AML after one cycle of ICE. The different salvage therapies were as follows: AMLHD93 sequential-HAM (S-HAM) for patients &lt;55 years of age [cytarabine 3g/m2 bid. days 1,2,8,9, mitoxantrone 10mg/m2 days 3,4,10,11], HAM for patients &gt;=55 …

Arginine Depletion in Combination with Canavanine Supplementation Induces Massive Cell Death in Myeloma Cells By Interfering with Their Protein Metabolism and Bypassing Potential Rescue Mechanisms

Abstract Introduction Although the therapeutic armamentarium against multiple myeloma has tremendously increased in recent years, it still remains an incurable disease. A highly promising novel anti-tumoral treatment strategy is to target specific non-redundant metabolic achilles heels of individual cancer entities. The semi-essential amino acid arginine can be synthesized from citrulline in most physiological tissues due to expression of the rate-limiting enzyme argininosuccinate synthetase 1 (ASS1). Various tumor entities do not express ASS1, therefore depend on the exogenous availability of arginine and pharmacological approaches to systemically deplete arginine are in phase I-III clinic…

Molecular Design of the Cαβ Interface Favors Specific Pairing of Introduced TCRαβ in Human T Cells

Abstract A promising approach to adoptive transfer therapy of tumors is to reprogram autologous T lymphocytes by TCR gene transfer of defined Ag specificity. An obstacle, however, is the undesired pairing of introduced TCRα- and TCRβ-chains with the endogenous TCR chains. These events vary depending on the individual endogenous TCR and they not only may reduce the levels of cell surface-introduced TCR but also may generate hybrid TCR with unknown Ag specificities. We show that such hybrid heterodimers can be generated even by the pairing of human and mouse TCRα- and TCRβ-chains. To overcome this hurdle, we have identified a pair of amino acid residues in the crystal structure of a TCR that …

Partial tyrosinase-specific self tolerance by HLA-A*0201-restricted cytotoxic T lymphocytes in mice and man

The human tyrosinase (hTyr) (369-377) cytotoxic T lymphocyte (CTL) epitope is presented by malignant melanoma and various nontransformed cells in association with human leukocyte antigen (HLA)-A*0201 (A2.1) and used for vaccination-based immunotherapy of melanoma patients. Its mouse homologue, mTyr (369-377), is naturally processed and bound by A2.1 with equivalent efficacy and thus enabled us to explore the effect of self tolerance on Tyr-specific T cells in different lines of A2.1 transgenic (Tg) mice and man. We found that self Tyr-reactive CTL in Tg mice and, importantly, in man were affected by partial tolerance resulting in only residual T lymphocytes of higher avidity for self Tyr al…

A Potent Tumor-Reactive p53-Specific Single-Chain TCR without On- or Off-Target Autoimmunity In Vivo

Genetic engineering of T cells with a T cell receptor (TCR) targeting tumor antigen is a promising strategy for cancer immunotherapy. Inefficient expression of the introduced TCR due to TCR mispairing may limit the efficacy and adversely affect the safety of TCR gene therapy. Here, we evaluated the safety and therapeutic efficiency of an optimized single-chain TCR (scTCR) specific for an HLA-A2.1-restricted (non-mutated) p53(264–272) peptide in adoptive T cell transfer (ACT) models using our unique transgenic mice expressing human p53 and HLA-A2.1 that closely mimic the human setting. Specifically, we showed that adoptive transfer of optimized scTCR-redirected T cells does not induce on-tar…

Human CD8+ memory and EBV-specific T cells show low alloreactivity in vitro and in CD34+ stem cell–engrafted NOD/SCID/IL-2Rγcnull mice

Current strategies in cellular immunotherapy of cancer and viral infections include the adoptive transfer of T cell receptor (TCR) and chimeric antigen receptor engineered T cells. When using transient RNA expression systems in clinical studies, multiple infusions with receptor-redirected T cells appear necessary. However, in allogeneic hematopoietic stem-cell transplantation, repeated transfer of donor-derived T cells increases the risk of alloreactive graft-versus-host disease. We investigated naive-derived (T N ), memory-derived (T M ), and Epstein Barr virus-specific (T EBV ) CD8 + T cell subsets for alloreactivity upon redirection with RNA encoding a cytomegalovirus-specific model TCR.…

The Impact of NFAT Inhibition on Neutrophil Effector Functions in Patients after Allogeneic Hematopoietic Stem Cell Transplantation and on Neutrophil Antifungal Defense and Myelopoiesis in Cyclosporin Α Treated and NFATc1LysM Mice

Abstract Background and Aims: Immunosuppressive medication e.g. by calcineurin inhibitors substantially contributes to the risk for opportunistic fungal infections in patients after allogeneic transplantation (HSCT). It is well known that the nuclear factor of activated T cells (NFAT) is an important transcription factor downstream of calcineurin especially in T cells. Additionally, recent data in rodent models indicate that NFAT also seems to play a relevant role in innate antifungal immune responses by polymorphonuclear neutrophils (PMN), as well as in regulation of myelopoiesis and myeloid differentiation. Methods: Firstly, isolated PMN from healthy donors were analyzed in vitro in absen…

Results of a HOVON/SAKK donor versus no-donor analysis of myeloablative HLA-identical sibling stem cell transplantation in first remission acute myeloid leukemia in young and middle-aged adults: benefits for whom?

Abstract The Dutch-Belgian Hemato-Oncology Cooperative Group and the Swiss Group for Clinical Cancer Research (HOVON-SAKK) collaborative study group evaluated outcome of patients (pts) with acute myeloid leukemia (AML) in first remission (CR1) entered in 3 consecutive studies according to a donor versus no-donor comparison. Between 1987 and 2004, 2287 pts were entered in these studies of whom 1032 pts (45%) without FAB M3 or t(15;17) were in CR1 after 2 cycles of chemotherapy, received consolidation treatment, and were younger than 55 years of age and therefore eligible for allogeneic hematopoietic stem cell transplantation (allo-SCT). An HLA-identical sibling donor was available for 326 pt…

Targeting positive regulatory domain I-binding factor 1 and X box-binding protein 1 transcription factors by multiple myeloma-reactive CTL.

Abstract Growing evidence indicates that multiple myeloma (MM) and other malignancies are susceptible to CTL-based immune interventions. We studied whether transcription factors inherently involved in the terminal differentiation of mature B lymphocytes into malignant and nonmalignant plasma cells provide MM-associated CTL epitopes. HLA-A*0201 (A2.1) transgenic mice were used to identify A2.1-presented peptide Ag derived from the plasma cell-associated transcriptional regulators, positive regulatory domain I-binding factor 1 (PRDI-BF1) and X box-binding protein 1 (XBP-1). A2.1-restricted CTL specific for PRDI-BF1 and XBP-1 epitopes efficiently killed a variety of MM targets. PRDI-BF1- and X…

Past, present and future of immunology in Mainz.

Cationic Amino Acid Transporter-1-Mediated Arginine Uptake Is Essential for Chronic Lymphocytic Leukemia Cell Proliferation and Viability

Interfering with tumor metabolism by specifically restricting the availability of extracellular nutrients is a rapidly emerging field of cancer research. A variety of tumor entities depend on the uptake of the amino acid arginine since they have lost the ability to synthesize it endogenously, that is they do not express the rate limiting enzyme for arginine synthesis, argininosuccinate synthase (ASS). Arginine transport through the plasma membrane of mammalian cells is mediated by eight different transporters that belong to two solute carrier (SLC) families. In the present study we found that the proliferation of primary as well as immortalized chronic lymphocytic leukemia (CLL) cells depen…