Comparison of human bone marrow stromal cells cultured in human platelet growth factors and fetal bovine serum.

BACKGROUND: Bone marrow stromal cells (BMSCs) have classically been cultured in media supplemented with fetal bovine serum (FBS). As an alternative to FBS, pooled solvent detergent apheresis platelets, HPGF-C18, was evaluated for BMSC culture. METHODS: A comparison of passage 2 BMSC growth revealed that 10% HPGF-C18 produced similar cell numbers as 20% FBS. Marrow aspirates from 5 healthy subjects were cultured for 4 passages in 10% HPGF-C18 or 20% FBS and were analyzed for proliferation, colony formation efficiency (CFE), surface marker expression, suppression of mixed lymphocyte reactions (MLRs), global gene and microRNA expression analysis. BMSC supernatant cytokine and growth factor concentrations were also compared. RESULTS: Primary cultures of marrow aspirates in 10% HPGF-C18 and 20% FBS yielded similar numbers and CFE. After 4 passages, 10% HPGF-C18 and 20% FBS yielded similar numbers of BMSCs, surface marker expression patterns and immunosuppression effects. Gene and microRNA expression analysis revealed that BMSCs cultured under the two conditions had distinct expression profiles. Gene Set Enrichment Analysis (GSEA) revealed HPGF-C18-cultured BMSCs were enriched in metabolic processing and biosynthetic pathways, cell proliferation and cell cycle pathways, and immune response pathways. FBS-cultured BMSCs were enriched in MAPK signaling, TGF-beta signaling, cell adhesion and extracellular matrix pathways. Differently expressed microRNAs were related to the osteogenesis of BMSCs. The supernatant of HPGF-C18 BMSCs had higher levels of PEDF and TGFB1 and lower levels of IL6, VEGF, SDF1 and PLGF. CONCLUSIONS: Traditional measures, expansion, surface marker expression and inhibition of MLRs suggest that BMSC cultured in HPGF-C18 and FBS were similar, but analysis at the molecular level revealed many differences. BMSCs cultured in HPGF-C18 should be assessed in specific functional assays that reflect application-specific potency before substituting FBS with HPGF-C18.

Generation of clinical-grade CD19-specific CAR-modified CD8+ memory stem cells for the treatment of human B-cell malignancies.

Long-lived, self-renewing, multipotent T memory stem cells (TSCM) can trigger profound and sustained tumor regression but their rareness poses a major hurdle to their clinical application. Presently, clinically compliant procedures to generate relevant numbers of this T-cell population are undefined. Here, we provide a strategy for deriving large numbers of clinical-grade tumor-redirected TSCM starting from naive precursors. CD8(+)CD62L(+)CD45RA(+) naive T cells enriched by streptamer-based serial-positive selection were activated by CD3/CD28 engagement in the presence of interleukin-7 (IL-7), IL-21, and the glycogen synthase-3ß inhibitor TWS119, and genetically engineered to express a CD19-specific chimeric antigen receptor (CD19-CAR). These conditions enabled the generation of CD19-CAR-modified CD8(+) TSCM that were phenotypically, functionally, and transcriptomically equivalent to their naturally occurring counterpart. Compared with CD8(+) T cells generated with clinical protocols currently under investigation, CD19-CAR-modified CD8(+) TSCM exhibited enhanced metabolic fitness and mediated robust, long-lasting antitumor responses against systemic acute lymphoblastic leukemia xenografts. This clinical-grade platform provides the basis for a phase 1 trial evaluating the activity of CD19-CAR-modified CD8(+) TSCM in patients with B-cell malignancies refractory to prior allogeneic hematopoietic stem cell transplantation.

Elutriated lymphocytes for manufacturing chimeric antigen receptor T cells.

BACKGROUND: Clinical trials of Chimeric Antigen Receptor (CAR) T cells manufactured from autologous peripheral blood mononuclear cell (PBMC) concentrates for the treatment of hematologic malignancies have been promising, but CAR T cell yields have been variable. This variability is due in part to the contamination of the PBMC concentrates with monocytes and granulocytes. METHODS: Counter-flow elutriation allows for the closed system separation of lymphocytes from monocytes and granulocytes. We investigated the use of PBMC concentrates enriched for lymphocytes using elutriation for manufacturing 8 CD19- and 5 GD2-CAR T cell products. RESULTS: When compared to PBMC concentrates, lymphocyte-enriched elutriation fractions contained greater proportions of CD3+ and CD56+ cells and reduced proportions of CD14+ and CD15+ cells. All 13 CAR T cell products manufactured using the elutriated lymphocytes yielded sufficient quantities of transduced CAR T cells to meet clinical dose criteria. The GD2-CAR T cell products contained significantly more T cells and transduced T cells than the CD19-CAR T cell products. A comparison of the yields of CAR T cells produced from elutriated lymphocytes with the yields of CAR T cells previous produced from cells isolated from PBMC concentrates by anti-CD3/CD28 bead selection or by anti-CD3/CD28 bead selection plus plastic adherence found that greater quantities of GD2-CAR T cells were produced from elutriated lymphocytes, but not CD19-CAR T cells. CONCLUSIONS: Enrichment of PBMC concentrates for lymphocytes using elutriation increased the quantity of GD2-CAR T cells produced. These results provide further evidence that CAR T cell expansion is inhibited by monocytes and granulocytes.

Acute GVHD in patients receiving IL-15/4-1BBL activated NK cells following T-cell-depleted stem cell transplantation.

Natural killer (NK) cells can enhance engraftment and mediate graft-versus-leukemia following allogeneic hematopoietic stem cell transplantation (HSCT), but the potency of graft-versus-leukemia mediated by naturally reconstituting NK cells following HSCT is limited. Preclinical studies demonstrate that activation of NK cells using interleukin-15 (IL-15) plus 4-1BBL upregulates activating receptor expression and augments killing capacity. In an effort to amplify the beneficial effects of NK cells post-HSCT, we conducted a first-in-human trial of adoptive transfer of donor-derived IL-15/4-1BBL-activated NK cells (aNK-DLI) following HLA-matched, T-cell-depleted (1-2 × 10(4) T cells/kg) nonmyeloablative peripheral blood stem cell transplantation in children and young adults with ultra-high-risk solid tumors. aNK-DLI were CD3(+)-depleted, CD56(+)-selected lymphocytes, cultured for 9 to 11 days with recombinant human IL-15 plus 4-1BBL(+)IL-15Rα(+) artificial antigen-presenting cells. aNK-DLI demonstrated potent killing capacity and displayed high levels of activating receptor expression. Five of 9 transplant recipients experienced acute graft-versus-host disease (GVHD) following aNK-DLI, with grade 4 GVHD observed in 3 subjects. GVHD was more common in matched unrelated donor vs matched sibling donor recipients and was associated with higher donor CD3 chimerism. Given that the T-cell dose was below the threshold required for GVHD in this setting, we conclude that aNK-DLI contributed to the acute GVHD observed, likely by augmenting underlying T-cell alloreactivity. This trial was registered at www.clinicaltrials.gov as #NCT01287104.

T cells expressing CD19 chimeric antigen receptors for acute lymphoblastic leukaemia in children and young adults: a phase 1 dose-escalation trial.

BACKGROUND: Chimeric antigen receptor (CAR) modified T cells targeting CD19 have shown activity in case series of patients with acute and chronic lymphocytic leukaemia and B-cell lymphomas, but feasibility, toxicity, and response rates of consecutively enrolled patients treated with a consistent regimen and assessed on an intention-to-treat basis have not been reported. We aimed to define feasibility, toxicity, maximum tolerated dose, response rate, and biological correlates of response in children and young adults with refractory B-cell malignancies treated with CD19-CAR T cells. METHODS: This phase 1, dose-escalation trial consecutively enrolled children and young adults (aged 1-30 years) with relapsed or refractory acute lymphoblastic leukaemia or non-Hodgkin lymphoma. Autologous T cells were engineered via an 11-day manufacturing process to express a CD19-CAR incorporating an anti-CD19 single-chain variable fragment plus TCR zeta and CD28 signalling domains. All patients received fludarabine and cyclophosphamide before a single infusion of CD19-CAR T cells. Using a standard 3 + 3 design to establish the maximum tolerated dose, patients received either 1 × 10(6) CAR-transduced T cells per kg (dose 1), 3 × 10(6) CAR-transduced T cells per kg (dose 2), or the entire CAR T-cell product if sufficient numbers of cells to meet the assigned dose were not generated. After the dose-escalation phase, an expansion cohort was treated at the maximum tolerated dose. The trial is registered with ClinicalTrials.gov, number NCT01593696. FINDINGS: Between July 2, 2012, and June 20, 2014, 21 patients (including eight who had previously undergone allogeneic haematopoietic stem-cell transplantation) were enrolled and infused with CD19-CAR T cells. 19 received the prescribed dose of CD19-CAR T cells, whereas the assigned dose concentration could not be generated for two patients (90% feasible). All patients enrolled were assessed for response. The maximum tolerated dose was defined as 1 × 10(6) CD19-CAR T cells per kg. All toxicities were fully reversible, with the most severe being grade 4 cytokine release syndrome that occurred in three (14%) of 21 patients (95% CI 3·0-36·3). The most common non-haematological grade 3 adverse events were fever (nine [43%] of 21 patients), hypokalaemia (nine [43%] of 21 patients), fever and neutropenia (eight [38%] of 21 patients), and cytokine release syndrome (three [14%) of 21 patients). INTERPRETATION: CD19-CAR T cell therapy is feasible, safe, and mediates potent anti-leukaemic activity in children and young adults with chemotherapy-resistant B-precursor acute lymphoblastic leukaemia. All toxicities were reversible and prolonged B-cell aplasia did not occur. FUNDING: National Institutes of Health Intramural funds and St Baldrick's Foundation.

Bone marrow-derived mesenchymal stromal cells harness purinergenic signaling to tolerize human Th1 cells in vivo.

The use of bone marrow-derived mesenchymal stromal cells (BMSC) in the treatment of alloimmune and autoimmune conditions has generated much interest, yet an understanding of the therapeutic mechanism remains elusive. We therefore explored immune modulation by a clinical-grade BMSC product in a model of human-into-mouse xenogeneic graft-versus-host disease (x-GVHD) mediated by human CD4(+) Th1 cells. BMSC reversed established, lethal x-GVHD through marked inhibition of Th1 cell effector function. Gene marking studies indicated BMSC engraftment was limited to the lung; furthermore, there was no increase in regulatory T cells, thereby suggesting a paracrine mechanism of BMSC action. BMSC recipients had increased serum CD73 expressing exosomes that promoted adenosine accumulation ex vivo. Importantly, immune modulation mediated by BMSC was fully abrogated by pharmacologic therapy with an adenosine A2A receptor antagonist. To investigate the potential clinical relevance of these mechanistic findings, patient serum samples collected pre- and post-BMSC treatment were studied for exosome content: CD73 expressing exosomes promoting adenosine accumulation were detected in post-BMSC samples. In conclusion, BMSC effectively modulate experimental GVHD through a paracrine mechanism that promotes adenosine-based immune suppression.

Myeloid cells in peripheral blood mononuclear cell concentrates inhibit the expansion of chimeric antigen receptor T cells.

BACKGROUND AIMS: Autologous chimeric antigen receptor (CAR) T-cell therapies have shown promising clinical outcomes, but T-cell yields have been variable. CD19- and GD2-CAR T-cell manufacturing records were reviewed to identify sources of variability. METHODS: CD19-CAR T cells were used to treat 43 patients with acute lymphocytic leukemia or lymphoma and GD2-CAR T cells to treat eight patients with osteosarcoma and three with neuroblastoma. Both types of CAR T cells were manufactured using autologous peripheral blood mononuclear cells (PBMC) concentrates and anti-CD3/CD28 beads for T-cell enrichment and simulation. RESULTS: A comparison of the first 6 GD2- and the first 22 CD19-CAR T-cell products manufactured revealed that GD2-CAR T-cell products contained fewer transduced cells than CD19-CAR T-cell products (147 ± 102 × 10(6) vs 1502 ± 1066 × 10(6); P = 0.0059), and their PBMC concentrates contained more monocytes (31.4 ± 12.4% vs 18.5 ± 13.7%; P = 0.019). Among the first 28 CD19-CAR T-cell products manufactured, four had poor expansion yielding less than 1 × 10(6) transduced T cells per kilogram. When PBMC concentrates from these four patients were compared with the 24 others, PBMC concentrates of poorly expanding products contained greater quantities of monocytes (39.8 ± 12.9% vs. 15.3 ± 10.8%, P = 0.0014). Among the patients whose CD19-CAR T cells expanded poorly, manufacturing for two patients was repeated using cryopreserved PBMC concentrates but incorporating a monocyte depleting plastic adherence step, and an adequate dose of CAR T cells was produced for both patients. CONCLUSIONS: Variability in CAR T-cell expansion is due, at least in part, to the contamination of the starting PBMC concentrates with monocytes.

Preliminary evaluation of a highly automated instrument for the selection of CD34+ cells from mobilized peripheral blood stem cell concentrates.

BACKGROUND: Cell selection is an important part of manufacturing cellular therapies. A new highly automated instrument, the CliniMACS Prodigy (Miltenyi Biotec), was evaluated for the selection of CD34+ cells from mobilized peripheral blood stem cell (PBSC) concentrates using monoclonal antibodies conjugated to paramagnetic particles. STUDY DESIGN AND METHODS: PBSCs were collected by apheresis from 36 healthy subjects given granulocyte-colony-stimulating factor (G-CSF) or G-CSF plus plerixafor. CD34+ cells from 11 PBSC concentrates were isolated with the automated CliniMACS Prodigy and 25 with the semiautomated CliniMACS Plus Instrument. RESULTS: The proportion of CD34+ cells in the selected products obtained with the two instruments was similar: 93.6 ± 2.6% for the automated and 95.7 ± 3.3% for the semiautomated instrument (p > 0.05). The recovery of CD34+ cells from PBSC concentrates was less for the automated than the semiautomated instrument (51.4 ± 8.2% vs. 65.1 ± 15.7%; p = 0.019). The selected products from both instruments contained few and similar quantities of platelets (PLTs) and red blood cells. The depletion of CD3+ cells was less with the automated instrument (4.34 ± 0.2 log depletion vs. 5.20 ± 0.35 log depletion; p < 1 × 10(-6) ). Removal of PLTs from PBSC concentrates by washing was associated with better CD34+ cell recovery. We explored the reasons for lower CD34+ cell recovery by the Prodigy and found that the nonselected cells for the Prodigy contained more PLTs than those for the CliniMACS Plus. CONCLUSIONS: CD34+ cells can be effectively selected from mobilized PBSC concentrates with the CliniMAC Prodigy, but the recovery of CD34+ cells and depletion of CD3+ cells was lower than with the semiautomated CliniMACS Plus Instrument.

CD34+ selection and the severity of oropharyngeal mucositis in total body irradiation-based allogeneic stem cell transplantation.

OBJECTIVE: The purpose of the present study was to evaluate the impact of ex vivo T cell depleted (TCD) by CD34+ selection on the incidence and severity of oropharyngeal mucositis (OM) after myeloablative allogeneic stem cell transplant (allo-SCT) with total body irradiation (TBI) conditioning. This approach has the advantage of avoiding methotrexate for graft versus host disease (GVHD) prophylaxis. PATIENTS AND METHODS: We analyzed the incidence and severity of OM in a cohort of 105 consecutive patients who underwent CD34+ selected (peripheral blood stem cells (PBSCs) from human leukocyte antigen (HLA)-identical siblings) allo-SCT with total body irradiation (TBI) conditioning. OM was graded by the World Health organization (WHO) and the Bearman regimen-related toxicity (RRT) scales. RESULTS: The incidence of WHO grade 3-4 OM was 34.3 %. There were no cases of grade 3-4 OM by the RRT scale. Significant correlation was found between the severity of OM and the use of intravenous (IV) narcotic medications (r (2) = 0.15, p = 0.004), total parenteral nutrition (TPN; r (2) = 0.68, p < 0.001), and hospital length of stay (LOS) (r (2) = 0.12, p = 0.01). DISCUSSION: TBI-induced OM can inflict significant morbidity in the early transplant period, and the incidence of WHO grade 3-4 OM can exceed 50 % when methotrexate is used for GVHD prophylaxis. In the CD34+ selected setting, methotrexate is avoided and the incidence of WHO grade 3-4 OM, use of TPN, and need for narcotic analgesia appear to be lower than historic evidence from standard T-replete allogeneic transplantation. CONCLUSION: We conclude that toxicity from OM is tolerable in CD34+ selected allo-SCT and should be prospectively measured in randomized trials comparing CD34+ selection versus T-replete transplantation.

Phase 2 clinical trial of rapamycin-resistant donor CD4+ Th2/Th1 (T-Rapa) cells after low-intensity allogeneic hematopoietic cell transplantation.

In experimental models, ex vivo induced T-cell rapamycin resistance occurred independent of T helper 1 (Th1)/T helper 2 (Th2) differentiation and yielded allogeneic CD4(+) T cells of increased in vivo efficacy that facilitated engraftment and permitted graft-versus-tumor effects while minimizing graft-versus-host disease (GVHD). To translate these findings, we performed a phase 2 multicenter clinical trial of rapamycin-resistant donor CD4(+) Th2/Th1 (T-Rapa) cells after allogeneic-matched sibling donor hematopoietic cell transplantation (HCT) for therapy of refractory hematologic malignancy. T-Rapa cell products, which expressed a balanced Th2/Th1 phenotype, were administered as a preemptive donor lymphocyte infusion at day 14 post-HCT. After T-Rapa cell infusion, mixed donor/host chimerism rapidly converted, and there was preferential immune reconstitution with donor CD4(+) Th2 and Th1 cells relative to regulatory T cells and CD8(+) T cells. The cumulative incidence probability of acute GVHD was 20% and 40% at days 100 and 180 post-HCT, respectively. There was no transplant-related mortality. Eighteen of 40 patients (45%) remain in sustained complete remission (range of follow-up: 42-84 months). These results demonstrate the safety of this low-intensity transplant approach and the feasibility of subsequent randomized studies to compare T-Rapa cell-based therapy with standard transplantation regimens.

Bone marrow mesenchymal stromal cells to treat tissue damage in allogeneic stem cell transplant recipients: correlation of biological markers with clinical responses.

Bone marrow mesenchymal stromal cells (BMSCs) have been used to treat acute graft-versus-host disease (GVHD) and other complications following allogeneic hematopoietic stem cell transplantation (SCT). We conducted a phase I trial using third party, early passage BMSCs for patients with steroid-refractory GVHD, tissue injury, or marrow failure following SCT to investigate safety and efficacy. To identify mechanisms of BMSC immunomodulation and tissue repair, patients were serially monitored for plasma GVHD biomarkers, cytokines, and lymphocyte phenotype. Ten subjects were infused a fixed dose of 2 × 10(6) BMSCs/kg intravenously weekly for three doses. There was no treatment-related toxicity (primary endpoint). Eight subjects were evaluable for response at 4 weeks after the last infusion. Five of the seven patients with steroid-refractory acute GVHD achieved a complete response, two of two patients with tissue injury (pneumomediastinum/pneumothorax) achieved resolution but there was no response in two subjects with delayed marrow failure. Rapid reductions in inflammatory cytokines were observed. Clinical responses correlated with a fall in biomarkers (Reg 3α, CK18, and Elafin) relevant for the site of GVHD or tissue injury. The GVHD complete responders survived significantly longer and had higher baseline absolute lymphocyte and central memory CD4 and CD8 counts. Cytokine changes also segregated with survival. These results confirm that BMSCs are associated with rapid clinical and biomarker responses in GVHD and tissue injury. However, BMSCs were ineffective in patients with prolonged GVHD with lower lymphocyte counts, which suggest that effective GVHD control by BMSCs requires a relatively intact immune system.

Human bone marrow stromal cell confluence: effects on cell characteristics and methods of assessment.

BACKGROUND AIMS: Ex vivo expansion and serial passage of human bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) is required to obtain sufficient quantities for clinical therapy. The BMSC confluence criteria used to determine passage and harvest timing vary widely, and the impact of confluence on BMSC properties remains controversial. The effects of confluence on BMSC properties were studied and confluence-associated markers were identified. METHODS: BMSC characteristics were analyzed as they grew from 50% to 100% confluence, including viability, population doubling time, apoptosis, colony formation, immunosuppression, surface marker expression, global gene expression and microRNA expression. In addition, culture supernatant protein, glucose, lactate and pH levels were analyzed. RESULTS: Confluence-dependent changes were detected in the expression of several cell surface markers: 39 culture supernatant proteins, 26 microRNAs and 2078 genes. Many of these surface markers, proteins, microRNAs and genes have been reported to be important in BMSC function. The pigment epithelium-derived factor/vascular endothelial growth factor ratio increased with confluence, but 80% and 100% confluent BMSCs demonstrated a similar level of immunosuppression of mixed lymphocyte reactions. In addition, changes in lactate and glucose levels correlated with BMSC density. CONCLUSIONS: BMSC characteristics change as confluence increases. 100% confluent BMSCs may have compromised pro-angiogenesis properties but may retain their immunomodulatory properties. Supernatant lactate and glucose levels can be used to estimate confluence and ensure consistency in passage and harvest timing. Flow cytometry or microRNA expression can be used to confirm that the BMSCs have been harvested at the appropriate confluence.

Counter-flow elutriation of clinical peripheral blood mononuclear cell concentrates for the production of dendritic and T cell therapies.

INTRODUCTION: Peripheral blood mononuclear cells (PBMC) concentrates collected by apheresis are frequently used as starting material for cellular therapies, but the cell of interest must often be isolated prior to initiating manufacturing. STUDY DESIGN AND METHODS: The results of enriching 59 clinical PBMC concentrates for monocytes or lymphocytes from patients with solid tumors or multiple myeloma using a commercial closed system semi-automated counter-flow elutriation instrument (Elutra, Terumo BCT) were evaluated for quality and consistency. Elutriated monocytes (n = 35) were used to manufacture autologous dendritic cells and elutriated lymphocytes (n = 24) were used manufacture autologous T cell therapies. Elutriated monocytes with >10% neutrophils were subjected to density gradient sedimentation to reduce neutrophil contamination and elutriated lymphocytes to RBC lysis. RESULTS: Elutriation separated the PBMC concentrates into 5 fractions. Almost all of the lymphocytes, platelets and red cells were found in fractions 1 and 2; in contrast, most of the monocytes, 88.6 ± 43.0%, and neutrophils, 74.8 ± 64.3%, were in fraction 5. In addition, elutriation of 6 PBMCs resulted in relatively large quantities of monocytes in fractions 1 or 2. These 6 PBMCs contained greater quantities of monocytes than the other 53 PBMCs. Among fraction 5 isolates 38 of 59 contained >10% neutrophils. High neutrophil content of fraction 5 was associated with greater quantities of neutrophils in the PBMC concentrate. Following density gradient separation the neutrophil counts fell to 3.6 ± 3.4% (all products contained <10% neutrophils). Following red cell lysis of the elutriated lymphocyte fraction the lymphocyte recovery was 86.7 ± 24.0% and 34.3 ± 37.4% of red blood cells remained. CONCLUSIONS: Elutriation was consistent and effective for isolating monocytes and lymphocytes from PBMC concentrates for manufacturing clinical cell therapies, but further processing is often required.

Metastatic lesions with and without interleukin-18-dependent genes in advanced-stage melanoma patients.

IL-18 is an immune-stimulating cytokine that promotes experimental melanoma metastasis via vascular endothelial growth factor (VEGF)-induced very late antigen (VLA)-4. We studied genes associated with the ability of melanoma cells to allow metastasis under IL-18 effects, and we verified their expression in metastatic lesions from patients with melanoma. Human melanoma cell lines with and without the IL-18 receptor (IL-18R)/VEGF/VLA-4-expressing phenotype were identified, and their metastatic potential was studied in nude mice. RNA from untreated and IL-18-treated melanoma phenotypes was hybridized to a cDNA microarray, and their signature genes were studied. RNA from primary and metastatic lesions from patients with melanoma was hybridized to a cDNA microarray to identify lesions with the transcript patterns of melanoma cells with and without the IL-18R/VEGF/VLA-4 phenotype. IL-18R/VEGF/VLA-4-expressing A375 and 1182 melanoma cells produced a higher metastasis number than 526 and 624.28 melanoma cells, not using this prometastatic pathway. Melanoma cells with and without the IL-18R/VEGF/VLA-4 phenotype had distinct transcript patterns. However, the type I transcriptional cluster, including cutaneous and lymph node metastases, but not the type II cluster, not including cutaneous metastases, had signature genes from IL-18-treated melanoma cells with, but not without, the IL-18R/VEGF/VLA-4 phenotype. Metastatic melanoma lesions with and without IL-18-dependent genes were identified, suggesting that melanoma metastasis developed via inflammation-dependent and inflammation-independent mechanisms. Signature genes from melanomas with and without the IL-18R/VEGF/VLA-4 phenotype may serve as diagnostic biomarkers of melanoma predisposition to prometastatic effects of IL-18.

15 kDa granulysin causes differentiation of monocytes to dendritic cells but lacks cytotoxic activity.

Granulysin is expressed as two isoforms by human cytotoxic cells: a single mRNA gives rise to 15 kDa granulysin, a portion of which is cleaved to a 9 kDa protein. Studies with recombinant 9 kDa granulysin have demonstrated its cytolytic and proinflammatory properties, but much less is known about the biologic function of the 15 kDa isoform. In this study, we show that the subcellular localization and functions of 9 and 15 kDa granulysin are largely distinct. Nine kilodalton granulysin is confined to cytolytic granules that are directionally released following target cell recognition. In contrast, 15 kDa granulysin is located in distinct granules that lack perforin and granzyme B and that are released by activated cytolytic cells. Although recombinant 9 kDa granulysin is cytolytic against a variety of tumors and microbes, recombinant 15 kDa granulysin is not. The 15 kDa isoform is a potent inducer of monocytic differentiation to dendritic cells, but the 9 kDa isoform is not. In vivo, mice expressing granulysin show markedly improved antitumor responses, with increased numbers of activated dendritic cells and cytokine-producing T cells. Thus, the distinct functions of granulysin isoforms have major implications for diagnosis and potential new therapies for human disease.

Quality controls in cellular immunotherapies: rapid assessment of clinical grade dendritic cells by gene expression profiling.

Cell-based immunotherapies are among the most promising approaches for developing effective and targeted immune response. However, their clinical usefulness and the evaluation of their efficacy rely heavily on complex quality control assessment. Therefore, rapid systematic methods are urgently needed for the in-depth characterization of relevant factors affecting newly developed cell product consistency and the identification of reliable markers for quality control. Using dendritic cells (DCs) as a model, we present a strategy to comprehensively characterize manufactured cellular products in order to define factors affecting their variability, quality and function. After generating clinical grade human monocyte-derived mature DCs (mDCs), we tested by gene expression profiling the degrees of product consistency related to the manufacturing process and variability due to intra- and interdonor factors, and how each factor affects single gene variation. Then, by calculating for each gene an index of variation we selected candidate markers for identity testing, and defined a set of genes that may be useful comparability and potency markers. Subsequently, we confirmed the observed gene index of variation in a larger clinical data set. In conclusion, using high-throughput technology we developed a method for the characterization of cellular therapies and the discovery of novel candidate quality assurance markers.

Leukemia cells induce changes in human bone marrow stromal cells.

BACKGROUND: Bone marrow stromal cells (BMSCs) are multipotent cells that support angiogenesis, wound healing, and immunomodulation. In the hematopoietic niche, they nurture hematopoietic cells, leukemia, tumors and metastasis. BMSCs secrete of a wide range of cytokines, growth factors and matrix proteins which contribute to the pro-tumorigenic marrow microenvironment. The inflammatory cytokines IFN-γ and TNF-α change the BMSC secretome and we hypothesized that factors produced by tumors or leukemia would also affect the BMSC secretome and investigated the interaction of leukemia cells with BMSCs. METHODS: BMSCs from healthy subjects were co-cultured with three myeloid leukemia cell lines (TF-1, TF-1α and K562) using a trans-well system. Following co-culture, the BMSCs and leukemia cells were analyzed by global gene expression analysis and culture supernatants were analyzed for protein expression. As a control, CD34+ cells were also cocultured with BMSCs. RESULTS: Co-culture induced leukemia cell gene expression changes in stem cell pluripotency, TGF-ß signaling and carcinoma signaling pathways. BMSCs co-cultured with leukemia cells up-regulated a number of proinflammatory genes including IL-17 signaling-related genes and IL-8 and CCL2 levels were increased in co-culture supernatants. In contrast, purine metabolism, mTOR signaling and EIF2 signaling pathways genes were up-regulated in BMSCs co-cultured with CD34+ cells. CONCLUSIONS: BMSCs react to the presence of leukemia cells undergoing changes in the cytokine and chemokine secretion profiles. Thus, BMSCs and leukemia cells both contribute to the creation of a competitive niche more favorable for leukemia stem cells.

Simplified process for the production of anti-CD19-CAR-engineered T cells.

BACKGROUND AIMS: Adoptive immunotherapy with the use of chimeric antigen receptor (CAR)-engineered T cells specific for CD19 has shown promising results for the treatment of B-cell lymphomas and leukemia. This therapy involves the transduction of autologous T cells with a viral vector and the subsequent cell expansion. We describe a new, simplified method to produce anti-CD19-CAR T cells. METHODS: T cells were isolated from peripheral blood mononuclear cell (PBMC) with anti-CD3/anti-CD28 paramagnetic beads. After 2 days, the T cells were added to culture bags pre-treated with RetroNectin and loaded with the retroviral anti-CD19 CAR vector. The cells, beads and vector were incubated for 24 h, and a second transduction was then performed. No spinoculation was used. Cells were then expanded for an additional 9 days. RESULTS: The method was validated through the use of two PBMC products from a patient with B-cell chronic lymphoblastic leukemia and one PBMC product from a healthy subject. The two PBMC products from the patient with B-cell chronic lymphoblastic leukemia contained 11.4% and 12.9% T cells. The manufacturing process led to final products highly enriched in T cells with a mean CD3+ cell content of 98%, a mean expansion of 10.6-fold and a mean transduction efficiency of 68%. Similar results were obtained from the PBMCs of the first four patients with acute lymphoblastic leukemia treated at our institution. CONCLUSIONS: We developed a simplified, semi-closed system for the initial selection, activation, transduction and expansion of T cells with the use of anti-CD3/anti-CD28 beads and bags to produce autologous anti-CD19 CAR-transduced T cells to support an ongoing clinical trial.

Differential gene expression profile of first-generation and second-generation rapamycin-resistant allogeneic T cells.

BACKGROUND AIMS: We completed a phase II clinical trial evaluating rapamycin-resistant allogeneic T cells (T-rapa) and now have evaluated a T-rapa product manufactured in 6 days (T-rapa(6)) rather than 12 days (T-Rapa(12)). METHODS: Using gene expression microarrays, we addressed our hypothesis that the two products would express a similar phenotype. The products had similar phenotypes using conventional comparison methods of cytokine secretion and surface markers. RESULTS: Unsupervised analysis of 34,340 genes revealed that T-rapa(6) and T-rapa(12) products clustered together, distinct from culture input CD4(+) T cells. Statistical analysis of T-rapa(6) products revealed differential expression of 19.3% of genes (n = 6641) compared with input CD4(+) cells; similarly, 17.8% of genes (n = 6147) were differentially expressed between T-rapa(12) products and input CD4(+) cells. Compared with input CD4(+) cells, T-rapa(6) and T-rapa(12) products were similar in terms of up-regulation of major gene families (cell cycle, stress response, glucose catabolism, DNA metabolism) and down-regulation (inflammatory response, immune response, apoptosis, transcriptional regulation). However, when directly compared, T-rapa(6) and T-rapa(12) products showed differential expression of 5.8% of genes (n = 1994; T-rapa(6) vs. T-rapa(12)). CONCLUSIONS: Second-generation T-rapa(6) cells possess a similar yet distinct gene expression profile relative to first-generation T-rapa(12) cells and may mediate differential effects after adoptive transfer.

Genomic scale analysis of racial impact on response to IFN-alpha.

Limited responsiveness to IFN-alpha in hepatitis C virus (HCV)-infected African-Americans compared to European Americans (AAs vs. EAs) hinders the management of HCV. Here, we studied healthy non-HCV-infected AA and EA subjects to test whether immune cell response to IFN-alpha is determined directly by race. We compared baseline and IFN-alpha-induced signal transducer and activator of transcription (STAT)-1, STAT-2, STAT-3, STAT-4, and STAT-5 protein and phosphorylation levels in purified T cells, global transcription, and a genomewide single-nucleotide polymorphism (SNP) profile of healthy AA and EA blood donors. In contrast to HCV-infected individuals, healthy AAs displayed no evidence of reduced STAT activation or IFN-alpha-stimulated gene expression compared to EAs. Although >200 genes reacted to IFN-alpha treatment, race had no impact on any of them. The only gene differentially expressed by the two races (NUDT3, P < 10(-7)) was not affected by IFN-alpha and bears no known relationship to IFN-alpha signaling or HCV pathogenesis. Genomewide analysis confirmed the self-proclaimed racial attribution of most donors, and numerous race-associated SNPs were identified within loci involved in IFN-alpha signaling, although they clearly did not affect responsiveness in the absence of HCV. We conclude that racial differences observed in HCV-infected patients in the responsiveness to IFN-alpha are unrelated to inherent racial differences in IFN-alpha signaling and more likely due to polymorphisms affecting the hosts' response to HCV, which in turn may lead to a distinct disease pathophysiology responsible for altered IFN signaling and treatment response.