Development of CAR T Cell Therapy in Children-A Comprehensive Overview.

CAR T cell therapy has revolutionized immunotherapy in the last decade with the successful establishment of chimeric antigen receptor (CAR)-expressing cellular therapies as an alternative treatment in relapsed and refractory CD19-positive leukemias and lymphomas. There are fundamental reasons why CAR T cell therapy has been approved by the Food and Drug administration and the European Medicines Agency for pediatric and young adult patients first. Commonly, novel therapies are developed for adult patients and then adapted for pediatric use, due to regulatory and commercial reasons. Both strategic and biological factors have supported the success of CAR T cell therapy in children. Since there is an urgent need for more potent and specific therapies in childhood malignancies, efforts should also include the development of CAR therapeutics and expand applicability by introducing new technologies. Basic aspects, the evolution and the drawbacks of childhood CAR T cell therapy are discussed as along with the latest clinically relevant information.

Investigation of product-derived lymphoma following infusion of piggyBac-modified CD19 chimeric antigen receptor T cells.

We performed a phase 1 clinical trial to evaluate outcomes in patients receiving donor-derived CD19-specific chimeric antigen receptor (CAR) T cells for B-cell malignancy that relapsed or persisted after matched related allogeneic hemopoietic stem cell transplant. To overcome the cost and transgene-capacity limitations of traditional viral vectors, CAR T cells were produced using the piggyBac transposon system of genetic modification. Following CAR T-cell infusion, 1 patient developed a gradually enlarging retroperitoneal tumor due to a CAR-expressing CD4+ T-cell lymphoma. Screening of other patients led to the detection, in an asymptomatic patient, of a second CAR T-cell tumor in thoracic para-aortic lymph nodes. Analysis of the first lymphoma showed a high transgene copy number, but no insertion into typical oncogenes. There were also structural changes such as altered genomic copy number and point mutations unrelated to the insertion sites. Transcriptome analysis showed transgene promoter-driven upregulation of transcription of surrounding regions despite insulator sequences surrounding the transgene. However, marked global changes in transcription predominantly correlated with gene copy number rather than insertion sites. In both patients, the CAR T-cell-derived lymphoma progressed and 1 patient died. We describe the first 2 cases of malignant lymphoma derived from CAR gene-modified T cells. Although CAR T cells have an enviable record of safety to date, our results emphasize the need for caution and regular follow-up of CAR T recipients, especially when novel methods of gene transfer are used to create genetically modified immune therapies. This trial was registered at www.anzctr.org.au as ACTRN12617001579381.

Prophylactic antigen-specific T-cells targeting seven viral and fungal pathogens after allogeneic haemopoietic stem cell transplant.

OBJECTIVES: Adoptive immunotherapy using donor-derived antigen-specific T-cells can prevent and treat infection after allogeneic haemopoietic stem cell transplant (HSCT). METHODS: We treated 11 patients with a prophylactic infusion of 2 × 107 cells per square metre donor-derived T-cells targeting seven infections (six viral and one fungal) following HSCT. Targeted pathogens were cytomegalovirus (CMV), Epstein-Barr virus (EBV), adenovirus, varicella zoster virus, influenza, BK virus (BKV) and Aspergillus fumigatus. RESULTS: T-cell products were successfully generated in all patients with 10 products responsive to 6 or 7 infections. T-cell infusions were associated with increases in antigen-experienced activated CD8+ T-cells by day 30. CMV, EBV and BKV reactivation occurred in the majority of patients and was well controlled except where glucocorticoids were administered soon after T-cell infusion. Three patients in that circumstance developed CMV tissue infection. No patient required treatment for invasive fungal infection. The most common CMV and EBV TCR clonotypes in the infusion product became the most common clonotypes seen at day 30 post-T-cell infusion. Donors and their recipients were recruited to the study prior to transplant. Grade III/IV graft-versus-host disease developed in four patients. At a median follow-up of 390 days post-transplant, six patients had died, 5 of relapse, and 1 of multi-organ failure. Infection did not contribute to death in any patient. CONCLUSION: Rapid reconstitution of immunity to a broad range of viral and fungal infections can be achieved using a multi-pathogen-specific T-cell product. The development of GVHD after T-cell infusion suggests that infection-specific T-cell therapy after allogeneic stem cell transplant should be combined with other strategies to reduce graft-versus-host disease.

Targeting CD83 in mantle cell lymphoma with anti-human CD83 antibody.

OBJECTIVES: Effective antibody-drug conjugates (ADCs) provide potent targeted cancer therapies. CD83 is expressed on activated immune cells including B cells and is a therapeutic target for Hodgkin lymphoma. Our objective was to determine CD83 expression on non-Hodgkin lymphoma (NHL) and its therapeutic potential to treat mantle cell lymphoma (MCL) which is currently an incurable NHL. METHODS: We analysed CD83 expression on MCL cell lines and the lymph node/bone marrow biopsies of MCL patients. We tested the killing effect of CD83 ADC in vitro and in an in vivo xenograft MCL mouse model. RESULTS: CD83 is expressed on MCL, and its upregulation is correlated with the nuclear factor κB (NF-κB) activation. CD83 ADC kills MCL in vitro and in vivo. Doxorubicin and cyclophosphamide (CP), which are included in the current treatment regimen for MCL, enhance the NF-κB activity and increase CD83 expression on MCL cell lines. The combination of CD83 ADC with doxorubicin and CP has synergistic killing effect of MCL. CONCLUSION: This study provides evidence that a novel immunotherapeutic agent CD83 ADC, in combination with chemotherapy, has the potential to enhance the efficacy of current treatments for MCL.

Rapidly expanded partially HLA DRB1-matched fungus-specific T cells mediate in vitro and in vivo antifungal activity.

Invasive fungal infections are a major cause of disease and death in immunocompromised hosts, including patients undergoing allogeneic hematopoietic stem cell transplant (HSCT). Recovery of adaptive immunity after HSCT correlates strongly with recovery from fungal infection. Using initial selection of lymphocytes expressing the activation marker CD137 after fungal stimulation, we rapidly expanded a population of mainly CD4+ T cells with potent antifungal characteristics, including production of tumor necrosis factor α, interferon γ, interleukin-17, and granulocyte-macrophage colony stimulating factor. Cells were manufactured using a fully good manufacturing practice-compliant process. In vitro, the T cells responded to fungal antigens presented on fully and partially HLA-DRB1 antigen-matched presenting cells, including when the single common DRB1 antigen was allelically mismatched. Administration of antifungal T cells lead to reduction in the severity of pulmonary and cerebral infection in an experimental mouse model of Aspergillus. These data support the establishment of a bank of cryopreserved fungus-specific T cells using normal donors with common HLA DRB1 molecules and testing of partially HLA-matched third-party donor fungus-specific T cells as a potential therapeutic in patients with invasive fungal infection after HSCT.

CD83: Activation Marker for Antigen Presenting Cells and Its Therapeutic Potential.

CD83 is a member of the immunoglobulin (Ig) superfamily and is expressed in membrane bound or soluble forms. Membrane CD83 (mCD83) can be detected on a variety of activated immune cells, although it is most highly and stably expressed by mature dendritic cells (DC). mCD83 regulates maturation, activation and homeostasis. Soluble CD83 (sCD83), which is elevated in the serum of patients with autoimmune disease and some hematological malignancies is reported to have an immune suppressive function. While CD83 is emerging as a promising immune modulator with therapeutic potential, some important aspects such as its ligand/s, intracellular signaling pathways and modulators of its expression are unclear. In this review we discuss the recent biological findings and the potential clinical value of CD83 based therapeutics in various conditions including autoimmune disease, graft-vs.-host disease, transplantation and hematological malignancies.

CD83 is a new potential biomarker and therapeutic target for Hodgkin lymphoma.

Chemotherapy and hematopoietic stem cell transplantation are effective treatments for most Hodgkin lymphoma patients, however there remains a need for better tumor-specific target therapy in Hodgkin lymphoma patients with refractory or relapsed disease. Herein, we demonstrate that membrane CD83 is a diagnostic and therapeutic target, highly expressed in Hodgkin lymphoma cell lines and Hodgkin and Reed-Sternberg cells in 29/35 (82.9%) Hodgkin lymphoma patient lymph node biopsies. CD83 from Hodgkin lymphoma tumor cells was able to trogocytose to surrounding T cells and, interestingly, the trogocytosing CD83+T cells expressed significantly more programmed death-1 compared to CD83-T cells. Hodgkin lymphoma tumor cells secreted soluble CD83 that inhibited T-cell proliferation, and anti-CD83 antibody partially reversed the inhibitory effect. High levels of soluble CD83 were detected in Hodgkin lymphoma patient sera, which returned to normal in patients who had good clinical responses to chemotherapy confirmed by positron emission tomography scans. We generated a human anti-human CD83 antibody, 3C12C, and its toxin monomethyl auristatin E conjugate, that killed CD83 positive Hodgkin lymphoma cells but not CD83 negative cells. The 3C12C antibody was tested in dose escalation studies in non-human primates. No toxicity was observed, but there was evidence of CD83 positive target cell depletion. These data establish CD83 as a potential biomarker and therapeutic target in Hodgkin lymphoma.

The Analysis of CD83 Expression on Human Immune Cells Identifies a Unique CD83+-Activated T Cell Population.

CD83 is a member of the Ig gene superfamily, first identified in activated lymphocytes. Since then, CD83 has become an important marker for defining activated human dendritic cells (DC). Several potential CD83 mRNA isoforms have been described, including a soluble form detected in human serum, which may have an immunosuppressive function. To further understand the biology of CD83, we examined its expression in different human immune cell types before and after activation using a panel of mouse and human anti-human CD83 mAb. The mouse anti-human CD83 mAbs, HB15a and HB15e, and the human anti-human CD83 mAb, 3C12C, were selected to examine cytoplasmic and surface CD83 expression, based on their different binding characteristics. Glycosylation of CD83, the CD83 mRNA isoforms, and soluble CD83 released differed among blood DC, monocytes, and monocyte-derived DC, and other immune cell types. A small T cell population expressing surface CD83 was identified upon T cell stimulation and during allogeneic MLR. This subpopulation appeared specifically during viral Ag challenge. We did not observe human CD83 on unstimulated human natural regulatory T cells (Treg), in contrast to reports describing expression of CD83 on mouse Treg. CD83 expression was increased on CD4+, CD8+ T, and Treg cells in association with clinical acute graft-versus-host disease in allogeneic hematopoietic cell transplant recipients. The differential expression and function of CD83 on human immune cells reveal potential new roles for this molecule as a target of therapeutic manipulation in transplantation, inflammation, and autoimmune diseases.

New utility of an old marker: serum low-density lipoprotein predicts histopathological response of neoadjuvant chemotherapy in locally advanced gastric cancer.

BACKGROUND: Although the correlation between metabolic abnormality and gastric cancer has been extensively investigated, the question of whether metabolic parameters might influence the efficacy of chemotherapy in locally advanced gastric cancer is still unanswered. In our present study, we investigated the relationship between serum fasting glucose, lipid levels, and histopathological response of neoadjuvant chemotherapy (NAC) in locally advanced gastric cancers. PATIENTS AND METHODS: A total of 128 patients were identified from a prospectively maintained database of patients with locally advanced gastric cancer who received NAC between July 2004 and December 2012. Histopathological response after NAC was analyzed according to Becker's tumor-regression grade. Univariate analyses and multivariable regression analyses were performed to determine the correlation between tumor size, differentiation, fasting glucose, lipid levels, and tumor histopathological response after NAC. RESULTS: Univariate analysis revealed that low-density lipoprotein level and total cholesterol, as well as tumor size and differentiation, correlated significantly with histopathological response. Low-density lipoprotein levels and tumor size were found to be independent predictors for histopathological response, according to multivariable regression analyses. CONCLUSION: In this observational, hypothesis-generating study, serum low-density lipoprotein measurement was found to be useful in predicting chemosensitivity to locally advanced gastric cancer patients undergoing NAC. Incorporation of serum low-density lipoprotein levels into individualized treatment protocols could be considered in clinical practice.

A circulating tumor cell cluster-based model for tumor metastasis (Hypothesis).

Metastasis is the major cause of mortality in patients with malignancies; however, the mechanisms of tumor cell dissemination and metastasis formation are obscure. Circulating tumor cells (CTCs) are believed to be a critical step for distant metastasis and are associated with a poor patient prognosis. The precise processes of metastasis formation from CTCs are vague. In the present study, we hypothesize that two CTC cluster-based mechanisms of tumor cell inoculation in ectopic organs may be viable: i) Formation of a micro-cancer embolus due to interception of CTC clusters by small vessels; and ii) formation of micrometastasis in an extravasation-dependent or -independent manner. Pathological evidence of micro-cancer emboli is critical for the verifications of this hypothesis. If proved true, this hypothesis will provide a novel perspective for cancer metastasis and has valuable clinical implications.

Immunotherapy for hepatocellular carcinoma: From basic research to clinical use.

Hepatocellular carcinoma (HCC) is a common cancer worldwide with a poor prognosis. Few strategies have been proven efficient in HCC treatment, particularly for those patients not indicated for curative resection or transplantation. Immunotherapy has been developed for decades for cancer control and is attaining more attention as a result of encouraging outcomes of new strategies such as chimeric antigen receptor T cells and immune checkpoint blockade. Right at the front of the new era of immunotherapy, we review the immunotherapy in HCC treatment, from basic research to clinical trials, covering anything from immunomodulators, tumor vaccines and adoptive immunotherapy. The mechanisms, efficacy and safety as well as the approach particulars are unveiled to assist readers to gain a concise but extensive understanding of immunotherapy of HCC.

Overexpression of ERα inhibits proliferation and invasion of MKN28 gastric cancer cells by suppressing ß-catenin.

The relationship between estrogen receptor (ER)α and patient prognosis has been identified in gastric cancer; however, the definite role of ERα in gastric cancer remains to be fully elucidated. The aim of the present in vitro study was to investigate the impact of ERα on cell proliferation, migration and invasion in gastric cancer cell lines. We investigated the biological effect of ERα overexpression on gastric carcinoma cells. An MKN28 gastric cancer cell line stably overexpressing ERα was established. The effect of ERα overexpression on cell growth was assessed by evaluating cell survival, colony formation, cell cycle progression and apoptosis. Cell migration and invasion were detected by Transwell migration/invasion assays. The protein levels of several potentially involved genes were determined by western blotting to elucidate the underlying molecular mechanisms. The Student's t-test was used to determine the statistical differences between various experimental and control groups, and one-way ANOVA test was used to determine the difference between three or more groups. The results showed that ERα overexpression significantly inhibited cell growth and proliferation, blocked cell entry into the G1/G0 phase and promoted cell apoptosis. In addition, ERα reduced the motility and invasion of gastric cancer cells. These phenotypes may partly be explained by a decrease in ß-catenin expression caused by ERα overexpression. ERα overexpression effectively inhibited cell growth and cancer progression by suppressing ß-catenin in gastric cancer, identifying ERα as a promising target with therapeutic potential for development of new approaches to treat gastric cancer.

Comparison of complete polyprotein sequences of two isolates of salmon alphavirus (SAV) type I and their behaviour in a salmonid cell line.

Salmon pancreas disease virus is an alphavirus (family Togaviridae) affecting mainly Atlantic salmon (Salmo salar L.). Both polyprotein sequences of the Scottish isolate (SAV4640) were determined and compared with those of Irish isolate SAVF93-125. High amino acid sequence similarity (99.4 %) was found. Six amino acid deletions were found in the E2 gene of SAV4640. SAVF93-125 demonstrated a high viral load in culture despite high Mx expression. Approximately 50 % of cells infected with SAVF93-125 exhibited a cytopathic effect by day 8. SAV4640 successfully entered the cells, inducing 10,500-fold higher Mx expression at day 2 compared to SAVF93-25; however, no replication was observed based on results of the nsP1 qRT-PCR.

A bacterial cysteine protease effector protein interferes with photosynthesis to suppress plant innate immune responses.

The bacterial pathogen Pseudomonas syringae pv tomato DC3000 suppresses plant innate immunity with effector proteins injected by a type III secretion system (T3SS). The cysteine protease effector HopN1, which reduces the ability of DC3000 to elicit programmed cell death in non-host tobacco, was found to also suppress the production of defence-associated reactive oxygen species (ROS) and callose when delivered by Pseudomonas fluorescens heterologously expressing a P. syringae T3SS. Purified His(6) -tagged HopN1 was used to identify tomato PsbQ, a member of the oxygen evolving complex of photosystem II (PSII), as an interacting protein. HopN1 localized to chloroplasts and both degraded PsbQ and inhibited PSII activity in chloroplast preparations, whereas a HopN1(D299A) non-catalytic mutant lost these abilities. Gene silencing of NtPsbQ in tobacco compromised ROS production and programmed cell death by DC3000. Our data reveal PsbQ as a contributor to plant immunity responses and a target for pathogen suppression.