Virus-specific T cells for the immunocompromised patient

While progress has been made in the treatment of both hematologic cancers and solid tumors, chemorefractory or relapsed disease often portends a dismal prognosis, and salvage chemotherapy or radiation expose patients to intolerable toxicities and may not be effective. Hematopoietic stem cell transplant offers the promise of cure for many patients, and while mismatched, unrelated or haploidentical donors are increasingly available, the recipients are at higher risk of severe immunosuppression and immune dysregulation due to graft versus host disease. Viral infections remain a primary cause of severe morbidity and mortality in this patient population. Again, many therapeutic options for viral disease are toxic, may be ineffective or generate resistance, or fail to convey long-term protection. Adoptive cell therapy with virus-specific T cells (VSTs) is a targeted therapy that is efficacious and has minimal toxicity in immunocompromised patients with CMV and EBV infections in particular. Products have since been generated specific for multiple viral antigens (multi-VST), which are not only effective but also confer protection in 70-90% of recipients when used as prophylaxis. Notably, these products can be generated from either virus-naive or virus-experienced autologous or allogeneic sources, including partially matched HLA-matched third-party donors. Obstacles to effective VST treatment are donor availability and product generation time. Banking of third-party VST is an attractive way to overcome these constraints and provide products on an as-needed basis. Other developments include epitope discovery to broaden the number of viral antigens targets in a single product, the optimization of VST generation from naive donor sources, and the modification of VSTs to enhance persistence and efficacy in vivo. © 2017 Houghtelin and Bollard

Children's Oncology Group's 2013 blueprint for research: Non‐Hodgkin lymphoma

Non‐Hodgkin lymphomas account for approximately 7% of cancers diagnosed in patients less than 20 years of age, with approximately 800 cases diagnosed annually at COG institutions. With current therapies, cure rates range from 70% to over 90%, even for children with disseminated disease. However, two major challenges need to be overcome: (i) to optimize upfront treatment to prevent relapse since prognosis for patients with relapsed disease remains poor and (ii) minimize long‐term side effects in survivors. Hence, the future initiatives for the treatment of pediatric NHL are to utilize novel targeted therapies to not only improve outcomes but to decrease bystander organ toxicities and late effects. Pediatr Blood Cancer 2013; 60: 979–984. © 2012 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97477/1/24416_ftp.pd

Adenoviral Infections in Hematopoietic Stem Cell Transplantation

AbstractAdenoviruses are lytic DNA viruses that are ubiquitous in human communities. In total, 51 different serotypes with varying tissue tropisms have been identified. Adenovirus infections, although frequent, are rarely fatal in immunocompetent individuals who have potent innate and adaptive immunity. But in immunosuppressed individuals, adenoviruses are a significant cause of morbidity and mortality, with limited treatment options. In particular, pediatric recipients of allogeneic hematopoietic stem cell transplantation frequently develop infections early in the posttransplantation period. Because the endogenous recovery of adenovirus-specific T cells has proven important in controlling infection, we explore the potential of adoptive T-cell immunotherapy as a therapeutic strategy. We discuss the advantages and limitations of T-cell therapy for the prophylaxis and treatment of adenovirus infection posttransplantation

Immunotherapy for Epstein-Barr Virus-Related Lymphomas

Latent EBV infection is associated with several malignancies, including EBV post-transplant lymphoproliferative disorders (LPD), Hodgkin and non-Hodgkin lymphomas, nasopharyngeal carcinoma and Burkitt lymphoma. The range of expression of latent EBV antigens varies in these tumors, which influences how susceptible the tumors are to immunotherapeutic approaches. Tumors expressing type III latency, such as in LPD, express the widest array of EBV antigens making them the most susceptible to immunotherapy. Treatment strategies for EBV-related tumors include restoring normal cellular immunity by adoptive immunotherapy with EBV-specific T cells and targeting the malignant B cells with monoclonal antibodies. We review the current immunotherapies and future studies aimed at targeting EBV antigen expression in these tumors

Improved methods for high-precision Pb-Pb dating of extra-terrestrial materials

Dating meteoritic materials by the Pb–Pb isochron method depends on constructing linear arrays typically defined by mixtures of initial and radiogenic Pb after the removal of terrestrial contaminant Pb. The method also depends on minimizing the amount of laboratory Pb blank added to the sample during processing and analyses. With the aim to analyze smaller sample sizes and decrease processing times, we have devised a new method for the construction of isochrons using the stepwise dissolution of meteoritic materials that better defines reduced amounts of Pb blank, reduces the risk of random anomalous Pb contamination, and increases sample throughput. Samples are processed in a PFA Teflon™ pipette tip fitted with a frit inside a heated, sealed chamber that can be manually over-pressured to expel reagents directly into a PFA Teflon™ vial below. With four independent chambers, three samples can be processed simultaneously with a fourth position to assess the Pb contribution of the combined blank and spike for each step. The matched blank-spike Pb for each step provides a specific blank estimate for each step that ensures a more accurate correction for non-sample Pb and, therefore, reduces the uncertainty on each analysis. We assess the performance of this new method by reporting the results of dating a fragment of a chondrule from the well-characterized CBa chondrite Gujba and compare these results with previously published data for this meteorite. The improvements reduce the minimum sample sizes that can be successfully dated by the Pb–Pb method, an important development for size-limited materials such as small chondrules and samples returned from space missions

Acute exercise enhances the expansion of cytotoxic T-cells specific to leukemia and melanoma antigens: implications for adoptive transfer immunotherapy?

INTRODUCTION: The ex vivo expansion of tumor-associated-antigen (TAA)-specific cytotoxic T-cells from healthy donors for adoptive transfer in cancer patients has been used successfully to prevent relapse after hematopoietic stem cell transplantation (HSCT). However, this therapy is limited by the difficulty in priming and expanding sufficient numbers of functional TAA-specific T-cells, as T-cells recognizing TAA are usually low in frequency and avidity in healthy donors. Furthermore, monocyte-derived dendritic cells (Mo-DC) are used for TAA-presentation, but their manufacture is limited by low blood monocyte numbers. Therefore, large and impractical numbers of blood cells are required to successfully expand TAA-specific T-cells. Acute exercise is well-known to transiently activate and increase the numbers of T-cells and monocytes in peripheral blood. We therefore hypothesized that the immune-enhancing effects of exercise could be harnessed to enhance the ex vivo expansion of TAA-specific T-cells for adoptive transfer immunotherapy. AIMS: To examine the effects of acute exercise on (1) the number and function of TAA-specific T-cells expanded ex vivo, and 2) the generation and function of mo-DC. METHODS: 12 healthy adults (mean ± SD: Age 27±2.6yrs) completed an acute bout of stair-running exercise (time: 104±17sec). Mo-DC generated from pre and post exercise blood samples were pulsed with the melanoma-associated-antigens MAGE-A4 and PRAME, the common tumor-antigen survivin, and the leukemia-associated-antigen WT-1. Autologous DC were used to expand TAA-specific T-cells obtained before and after exercise over 14-days. T-cells were enumerated and phenotyped by flow cytometry and function was assessed by ELISPOT and antigen-specific cytotoxicity. RESULTS: A greater number of mo-DC were generated from post-exercise blood samples (pre: 2.0±1.0 X106cells, post: 5.2±2.6 X106cells). This was due to the 1.7 fold increase in blood monocytes post-exercise, as the number of mo-DC generated per input CD14+cell did not differ (pre: 0.40±0.25, post: 0.59±0.36). Total T-cell expansion was increased post-exercise (fold-increase: pre: 2.48±0.75, post: 2.90±0.74). ELISPOT revealed that the majority of donors had enrichment in TAA-specific T-cells post-exercise, as T-cell lines expanded from post-exercise samples exhibited an increased interferon-gamma response to TAA compared to T-cell lines expanded from pre-exercise samples. Exercise had no effect on T-cell phenotype or antigen-specific cytotoxicity in the expanded cells. CONCLUSION: These data indicate that a single bout of exercise enhances mo-DC generation and the expansion of TAA-specific T-cells ex vivo. Exercise may therefore serve as an adjuvant to enhance the expansion of TAA-specific T-cells in healthy donors and improve the efficacy of adoptive transfer therapy in cancer patients

Ex Vivo Expanded Multi-Specific Cytotoxic T Lymphocytes Derived from HIV+ Patients and HIV Negative Donors Using GMP Compliant Methodologies Recognize Multiple HIV Antigens and Suppress HIV Replication

Coderch de Sentmenat, José Antoni

Vorinostat Renders the Replication-Competent Latent Reservoir of Human Immunodeficiency Virus (HIV) Vulnerable to Clearance by CD8 T Cells

Latently human immunodeficiency virus (HIV)-infected cells are transcriptionally quiescent and invisible to clearance by the immune system. To demonstrate that the latency reversing agent vorinostat (VOR) induces a window of vulnerability in the latent HIV reservoir, defined as the triggering of viral antigen production sufficient in quantity and duration to allow for recognition and clearance of persisting infection, we developed a latency clearance assay (LCA). The LCA is a quantitative viral outgrowth assay (QVOA) that includes the addition of immune effectors capable of clearing cells expressing viral antigen. Here we show a reduction in the recovery of replication-competent virus from VOR exposed resting CD4 T cells following addition of immune effectors for a discrete period. TAKE HOME MESSAGE: VOR exposure leads to sufficient production of viral protein on the cell surface, creating a window of vulnerability within this latent reservoir in antiretroviral therapy (ART)-suppressed HIV-infected individuals that allows the clearance of latently infected cells by an array of effector mechanisms