NIMG-59. RADIOMICS-PREDICTED T CELL DYNAMICS STRATIFY SURVIVAL AFTER DENDRITIC CELL VACCINE THERAPY FOR PRIMARY GLIOBLASTOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi142-vi143
Author(s):  
Kamila Bond ◽  
Andrea Hawkins-Daarud ◽  
Gustavo De Leon ◽  
Lee Curtin ◽  
Javier Urcuyo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cox Proportional Hazards ◽  
Post Treatment ◽  
Vaccine Therapy ◽  
Cell Vaccine ◽  
Imaging Features ◽  
Primary Glioblastoma ◽  
Cell Abundance ◽  
Dc Vaccine

Abstract INTRODUCTION Dendritic cells (DCs) are potent antigen presenting cells that can be exploited to initiate an adaptive anti-tumoral immune response. DC vaccine clinical trials for primary glioblastoma (GBM) have reported prolonged progression-free survival without any impact on overall survival (OS). We report a radiomics approach that identifies a subpopulation of patients with prolonged OS in clinical trial MC1272. METHODS Twenty adults with primary GBM undergoing standard-of-care therapy were enrolled in MC1272. Autologous DCs were pulsed with allogenic GBM cell lines to generate vaccines that were administered for up to twelve cycles. Standard brain imaging was obtained at the initiation of treatment and two months afterwards. An independent cohort of image-localized biopsies underwent RNA sequencing followed by cellular deconvolution to estimate T cell abundance. A machine learning model was trained to predict intratumoral T cell abundance from imaging features, and the model was applied to MC1272 patient imaging. RESULTS Voxelwise predictions of T cell abundance were generated for each patient’s pre- and post-treatment images. The difference in total intratumoral T cell abundance between imaging timepoints classified patients into increasing or decreasing T cell groups. Patients whose T cells increased had longer OS (median, 21 months) than those whose T cells decreased (median, 10 months; p=0.0035). The significance remained in a Cox proportional hazards analysis that adjusted for patient age and sex (p=0.011). CONCLUSIONS A spatially-resolved radiomics model detected that an intratumoral T cell influx after DC vaccine therapy was associated with prolonged OS. The “post-treatment” imaging in this study was obtained a mere two months after DC vaccine initiation, suggesting that our radiomics model can provide an early indication of treatment responsiveness and prognosis in these patients.

KY1044 to target the ICOS pathways inducing intratumoral Treg depletion and agonism of effector T cells: Preliminary pharmacodynamic markers from a phase 1/2 multicenter trial.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2626-2626
Author(s):  
Chia-Chi Lin ◽  
Aung Naing ◽  
Manish R. Patel ◽  
Howard A. Burris III ◽  
Giuseppe Curigliano ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Phase 1 ◽  
Single Agent ◽  
Effector T Cells ◽  
Post Treatment ◽  
Target Engagement ◽  
Treg Depletion ◽  
Gm Csf ◽  
Tumor Biopsies

2626 Background: Inducible T-cell co-stimulator (ICOS) is an important co-stimulatory receptor on effector T cells (Teffs) that also promotes tumor growth due to its high expression on regulatory T cells (Tregs). KY1044 is a fully human IgG1 that targets ICOS, acting via a dual mode of action (MoA) by depleting ICOShigh Tregs and stimulating ICOSLow Teffs. A Phase 1/2 clinical trial (NCT03829501) is currently assessing the safety and preliminary efficacy of KY1044, as a single agent and in combination with atezolizumab, in subjects with advanced relapsed/refractory malignancies. Using longitudinal blood samples and tumor biopsies, we aim to correlate KY1044 target engagement levels with pharmacodynamic (PD) properties (e.g. dual MoA) in the tumor microenvironment (TME) and the circulation. Methods: Phase 1 subjects were enrolled in dose escalation and enrichment cohorts to evaluate the effect of KY1044 as monotherapy (0.8 – 240 mg) Q3W and in combination (0.8 – 80 mg) with atezolizumab (1200 mg) Q3W. PBMCs, plasma and tumor biopsies were collected over the first 3 cycles to confirm target engagement and KY1044 MoA. The sample analysis included: immunohistochemistry (IHC) of tumor samples (ICOS, FOXP3 and CD8); circulating T cell immunoprofiling and receptor occupancy by chip-cytometry; PBMC and tumor sample pre- and post-treatment transcriptomic analysis; and the assessment of circulating cytokines (e.g. GM-CSF). Results: As assessed in PBMCs, full/prolonged ICOS target engagement on T cells was confirmed in subjects receiving a flat dose of 8 to 240 mg, while partial/transient saturation was observed at lower doses (0.8-2.4 mg). The target engagement was not affected by atezolizumab. The immune cell profiling showed changes in some populations, but there was no significant depletion of peripheral ICOS+ cells. In contrast, pre- and post-treatment IHC analysis of ICOS+/FOXP3+ cells in tumor biopsies confirmed a KY1044-dose dependent reduction of ICOS+ Tregs and maintenance of CD8+ T cells in the TME. Together, this resulted in an increased intratumoral CD8+/ICOS+ Treg ratio at all doses, plateauing from subjects receiving a flat KY1044 dose of 8 mg. KY1044-dependent agonism was indirectly assessed by measuring circulating cytokine levels. A post-dosing transient induction of GM-CSF was evident in subjects dosed with KY1044 at the 0.8 and 2.4 mg dose, whereas minimal induction was observed at dose of 8 mg and higher. Conclusions: LongitudinalPDdata confirmed the expected KY1044 MoA, namely ICOS Treg depletion and increased CD8/ICOS Treg ratio in the TME as well as T cell co-stimulation. The observed PD responses are currently being further explored in a more homogenous patient population.

scholarly journals Immune cell topography predicts response to PD-1 blockade in cutaneous T cell lymphoma

2020 ◽  
Author(s):  
Darci Phillips ◽  
Magdalena Matusiak ◽  
Belén Rivero Gutierrez ◽  
Salil S. Bhate ◽  
Graham L. Barlow ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Clinical Response ◽  
Tumor Cells ◽  
Spatial Organization ◽  
Cell Lymphoma ◽  
Post Treatment ◽  
T Cell Lymphoma ◽  
T Cell Subsets ◽  
Cutaneous T Cell Lymphoma

Anti-PD-1 immunotherapies have transformed cancer treatment, yet the determinants of clinical response are largely unknown. We performed CODEX multiplexed tissue imaging and RNA sequencing on 70 tumor regions from 14 advanced cutaneous T cell lymphoma (CTCL) patients enrolled in a clinical trial of pembrolizumab therapy. Clinical response was not associated with the frequency of tumor-infiltrating T cell subsets, but rather with striking differences in the spatial organization and functional immune state of the tumor microenvironment (TME). After treatment, pembrolizumab responders had a localized enrichment of tumor and CD4+ T cells, which coincided with immune activation and cytotoxic PD-1+ CD4+ T cells. In contrast, non-responders had a localized enrichment of Tregs pre- and post-treatment, consistent with a persistently immunosuppressed TME and exhausted PD-1+ CD4+ T cells. Integrating these findings by computing the physical distances between PD-1+ CD4+ T cells, tumor cells, and Tregs revealed a spatial biomarker predictive of pembrolizumab response. Finally, the chemokine CXCL13 was upregulated in tumor cells in responders post-treatment, suggesting that chemoattraction of PD-1+ CD4+ T cells towards tumor cells facilitates a positive outcome. Together, these data show that T cell topography reflects the balance of effector and suppressive activity within the TME and predicts clinical response to PD-1 blockade in CTCL.

scholarly journals Enhanced T Cell Responses Induced by a Necrotic Dendritic Cell Vaccine, Expressing HCV NS3

2020 ◽  
Vol 11 ◽  
Author(s):  
Zelalem A. Mekonnen ◽  
Makutiro G. Masavuli ◽  
Wenbo Yu ◽  
Jason Gummow ◽  
Dawn M. Whelan ◽  
...  
Keyword(s):  
T Cell ◽  
Vaccination Strategy ◽  
T Cell Responses ◽  
Dendritic Cell Vaccine ◽  
Effector Memory ◽  
Cell Vaccine ◽  
Cell Mediated Immunity ◽  
Structural Protein ◽  
Cell Responses ◽  
Dc Vaccine

A vaccine that induces potent, broad and sustained cell-mediated immunity, resulting in effective memory has the potential to restrict hepatitis C (HCV) virus infection. Early, multi-functional CD4+ and CD8+ T cell responses against non-structural protein 3 (NS3) have been associated with HCV clearance. Necrotic cells generate strong immune responses and represent a major antigenic source used by dendritic cells (DC) for processing and presentation, but there is conflicting evidence as to their immunogenicity in vaccination. Immunization with DC loaded with viral antigens has been done in the past, but to date the immunogenicity of live vs. necrotic DC vaccines has not been investigated. We developed a DC2.4 cell line stably expressing HCV NS3, and compared the NS3-specific responses of live vs. necrotic NS3 DC. Vaccination of mice with necrotic NS3 DC increased the breadth of T-cell responses and enhanced the production of IL-2, TNF-α, and IFN-γ by effector memory CD4+ and CD8+T cells, compared to mice vaccinated with live NS3 DC. A single dose of necrotic NS3 DC vaccine induced a greater influx and activation of cross-presenting CD11c+ CD8α+ DC and necrosis-sensing Clec9A+ DC in the draining lymph nodes. Furthermore, using a hydrodynamic challenge model necrotic NS3 DC vaccination resulted in enhanced clearance of NS3-positive hepatocytes from the livers of vaccinated mice. Taken together, the data demonstrate that necrotic DC represent a novel and exciting vaccination strategy capable of inducing broad and multifunctional T cell memory.

scholarly journals Whole Blood Profiling of T-cell-Derived microRNA Allows the Development of Prognostic models in Inflammatory Bowel Disease

2020 ◽  
Vol 14 (12) ◽  
pp. 1724-1733
Author(s):  
R Kalla ◽  
A T Adams ◽  
N T Ventham ◽  
N A Kennedy ◽  
R White ◽  
...  
Keyword(s):  
Inflammatory Bowel Disease ◽  
T Cells ◽  
T Cell ◽  
Bowel Disease ◽  
Whole Blood ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Prognostic Models ◽  
Inflammatory Bowel ◽  
Treatment Escalation

Abstract Background MicroRNAs [miRNAs] are cell-specific small non-coding RNAs that can regulate gene expression and have been implicated in inflammatory bowel disease [IBD] pathogenesis. Here we define the cell-specific miRNA profiles and investigate its biomarker potential in IBD. Methods In a two-stage prospective multi-centre case control study, next generation sequencing was performed on a discovery cohort of immunomagnetically separated leukocytes from 32 patients (nine Crohn’s disease [CD], 14 ulcerative colitis [UC], eight healthy controls) and differentially expressed signals were validated in whole blood in 294 patients [97 UC, 98 CD, 98 non-IBD, 1 IBDU] using quantitative PCR. Correlations were analysed with phenotype, including need for early treatment escalation as a marker of progressive disease using Cox proportional hazards. Results In stage 1, each leukocyte subset [CD4+ and CD8+ T-cells and CD14+ monocytes] was analysed in IBD and controls. Three specific miRNAs differentiated IBD from controls in CD4+ T-cells, including miR-1307-3p [p = 0.01], miR-3615 [p = 0.02] and miR-4792 [p = 0.01]. In the extension cohort, in stage 2, miR-1307-3p was able to predict disease progression in IBD (hazard ratio [HR] 1.98, interquartile range [IQR]: 1.20–3.27; logrank p = 1.80 × 10–3), in particular CD [HR 2.81; IQR: 1.11–3.53, p = 6.50 × 10–4]. Using blood-based multimarker miRNA models, the estimated chance of escalation in CD was 83% if two or more criteria were met and 90% for UC if three or more criteria are met. Interpretation We have identified and validated unique CD4+ T-cell miRNAs that are differentially regulated in IBD. These miRNAs may be able to predict treatment escalation and have the potential for clinical translation; further prospective evaluation is now indicated.

scholarly journals Intratumoral TIGIT+ CD8+ T-cell infiltration determines poor prognosis and immune evasion in patients with muscle-invasive bladder cancer

2020 ◽  
Vol 8 (2) ◽  
pp. e000978
Author(s):  
Zhaopei Liu ◽  
Quan Zhou ◽  
Zewei Wang ◽  
Hongyu Zhang ◽  
Han Zeng ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
T Cells ◽  
T Cell ◽  
Invasive Bladder Cancer ◽  
Th2 Cells ◽  
Cancer Center ◽  
Muscle Invasive Bladder Cancer ◽  
Cell Abundance ◽  
Immune Contexture ◽  
Muscle Invasive

BackgroundT-cell immunoglobulin and ITIM domain (TIGIT) is identified as a novel checkpoint receptor that can facilitate immune escape via mediating T-cell exhaustion in tumors. However, the clinical significance and immune contexture correlation of intratumoral TIGIT+ CD8+ T-cells remain to be further explored in muscle-invasive bladder cancer (MIBC).Methods259 patients with MIBC from two clinical centers (Zhongshan Hospital, n=141; Shanghai Cancer Center, n=118) were analyzed to evaluate the prognostic value and immune contexture association of TIGIT+ CD8+ T-cells through immunohistochemistry. Fresh tumor tissue samples from 26 patients with MIBC were examined to discover the phenotype of this CD8 subpopulation by flow cytometry.ResultsHigh infiltration of intratumoral TIGIT+ CD8+ T-cells predicted poor overall survival (OS) and recurrence-free survival (RFS) in MIBC. For patients with stage II MIBC with low infiltration of TIGIT+ CD8+ cells, adjuvant chemotherapy (ACT) could significantly prolong their OS and RFS. Intratumoral TIGIT+ CD8+ T-cell abundance was correlated with impaired CD8+ T-cell cytotoxicity and exhibited production of immunosuppressive cytokine IL-10. Further analysis of tumor-infiltrating immune cell landscape revealed TIGIT+ CD8+ T-cells were associated with suppressive immune contexture, including Th2 cells, regulatory T-cells, mast cells and neutrophils.ConclusionIntratumoral TIGIT+ CD8+ T-cell abundance could serve as an independent prognosticator for clinical outcome and a predictive biomarker for inferior ACT responsiveness. Intratumoral TIGIT+ CD8+ T-cell abundance correlated with dampened CD8+ T-cell antitumor immunity and immunosuppressive contexture abundance, highlighting a tumor-promoting role of TIGIT+ CD8+ T-cells.

Dendritic Cells (DC) Generated from AML Blasts Express Leukemia Associated Antigens Eliciting Specific Cytotoxic T Cell Responses in the Autologous Host after DC Vaccination.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1812-1812 ◽  
Author(s):  
Li Li ◽  
Peter Reinhardt ◽  
Iwona Hus ◽  
Jacek Rolinski ◽  
Anna Dmoszynska ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mrna Expression ◽  
Cytotoxic T Cell ◽  
Fish Analysis ◽  
Specific Response ◽  
Proteinase 3 ◽  
Cpg Odn ◽  
Dc Vaccine ◽  
Significant Difference

Abstract Several groups including ours demonstrated the generation of DC from AML blasts (AML-DC). FISH analysis has been employed to assess the origin of AML-DC from AML blasts. For clinical application, this approach is not feasible because of the restriction of AML-DC in number. Therefore we established an alternative system to prove the origin of the AML-DC, using quantitative real-time PCR to test the mRNA expression of the leukemia associated antigens (LAAs) preferentially expressed antigen in melanoma (PRAME), proteinase 3, the receptor for hyaluronic acid mediated motility (RHAMM/CD168) and the Wilms tumor gene 1 (WT-1). An elevated PCR signal for PRAME was detected in 7/12 AML-DC preparations when compared with AML blasts, for RHAMM/CD168 in 6/12 AML-DC preparations, but only in 2/12 respectively 1/12 AML-DC for WT-1 and proteinase 3. All preparations showed a strong expression of at least one of the LAAs examined. The stronger PCR signals after DC generation for PRAME and RHAMM/CD168 characterize these two LAAs as favourable target structures for immunotherapies. AML-DC positive for RHAMM/CD168 mRNA tested also positive for the protein as demonstrated by immunocytochemistry. In PRAME mRNA positive AML-DC, the described PRAME derived decamer epitope peptide ALYVDSLFFL was recognized by specific T cells as proven by chromium-51 release assay, thus proving that the mRNA assessment for RHAMM/CD168 and PRAME has an immunological significance. For five patients, AML-DC were generated under good manufacturing practice (GMP) conditions. 5x10E6 AML-DC were injected s.c. in the vicinity of inguinal lymph nodes four times at a biweekly interval. No severe adverse effects were observed after DC vaccination. One patient with AML FAB M4 required blood transfusions and remained in stable condition for several months, but eventually died from pneumonia 13 months after the DC vaccinations. A 70 year-old women with a secondary AML received a complete course of AML-DC vaccinations. During the period of 4 vaccinations, the blast level dropped from 8% in the PB to 0% and no side effects were noted. Two patients died from cranial hemorrhage after the first vaccination due to thrombocytopenia caused by the AML. One patient is still under DC vaccination. ELISPOT analysis of the first two patients revealed a significant increase in interferon gamma and granzyme B releasing CD8+ T cells recognizing a leukemic blast lysate as well as specifically RHAMM derived peptides, when compared to the initial T cell frequency. Potentiation of such an AML-DC vaccine might become feasible by the addition of adjuvants such as CPG-rich oligodeoxyribonucleotides (CPG-ODN) or lipopolysaccharides (LPS). We therefore investigated the presence of receptors for such adjuvants, i.e Toll-like receptors (TLRs) on AML-DC. Quantitative mRNA expression of TLR-2, 4 and 9 in AML-DC and DC generated of monocytes from healthy volunteers did not display any significant difference. In summary, DC could be generated from AML blasts and preserved or even upregulated LAA expression. DC vaccination was well tolerated and resulted in an enhanced and specific response of cytotoxic T cells. The adequate expression of TLRs renders potentiation of the AML-DC vaccine described here by e.g. CPG-ODN possible.

Subclinical GVHD Impairs Responses to Dendritic Cell Vaccines Following Allogeneic Transplantation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 571-571
Author(s):  
Sarah Herby ◽  
Matthew Milliron ◽  
Crystal Mackall ◽  
Terry Fry
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Physical Symptoms ◽  
Third Party ◽  
Donor Strain ◽  
Vaccine Responses ◽  
Dc Vaccine ◽  
Dc Vaccines ◽  
A Minor

Abstract Background: Although allogeneic graft versus tumor responses represent the most potent form of immunotherapy, recurrent malignancy remains a major cause of post-transplant mortality. Thus, strategies to enhance GVT are needed to improve outcomes. Dendritic cell (DC) vaccines can potently enhance anti-tumor immunity in the autologous setting. The impact of alloreactivity on DC vaccine responses is not known, but the potency of the GVT effect suggests that mild alloreactivity might enhance vaccine responses to third party antigens. Methods: To determine the effect of a minor histocompatibility mismatch on DC vaccine responses, lethally irradiated female C3H.SWxC57BL/6 and C3H.SW recipients were transplanted with T cell depleted (TCD) C3H.SW bone marrow (BM). On days 14 and 28, recipients received donor-type lymph node cells containing mature T cells (DLI, 1 x 10^6, 5 x 10^6, or 10 x 10^6 IV). To immunize against the male antigenic complex (HY), BM-derived, anti-CD40 activated donor strain male DC were administered IP at the same time as the DLI. At Day 35, HY specific immune responses were measured using interferon γ ELISPOT against the dominant (UTY) and subdominant (SMCY) class I epitopes and dominant class II epitope (DBY). In some experiments, rhIL-7 and rhIL-15 were administered (5 mcg/day IP) from day 14 to 35. Results: In syngeneic recipients, robust HY responses were observed at all DLI doses, consistent with rapid T cell reconstitution via the thymus. Allogeneic recipients demonstrated mild weight loss and decreased splenic cellularity as the DLI dose was increased, consistent with the development of mild GVHD. However, even recipients receiving the highest DLI dose recovered completely and had none of the major physical symptoms of GVHD. Increasing DLI dose from 1 x 10^6 to 10 x 10^6 paradoxically led to a marked decrease in the median total number of T cells/spleen responding to UTY, SMCY, and DBY (9196 at 1 x 10^6 vs 897 at 10 x 10^6, p = .01; 15662 vs 2854, p= .02; 10257 vs 4227, p = .02). To test whether the presence of alloreactive T cells were necessary for this effect, C3H.SW minor antigen reactive T cells were deleted from B6-derived DLI. TCD B6 BM was transplanted into C3H.SWxC57BL/6 mice and at 5 weeks LN cells were collected and transferred as DLI. Strikingly, transfer of 10 x 10^6 tolerized DLI did not result in a loss of HY vaccine responses when compared to transfer of non-tolerized DLI (UTY, 3888 vs 21075, p= .05; SMCY, 7135 vs 21126, p = .018; DBY, 7117 vs 29201, p= .006). Although IL-7 and IL-15 can potently enhance DC vaccine responses in the syngeneic setting, these cytokines did not improve vaccine responses in allogeneic recipients. Conclusions: Using a minor mismatched allogeneic transplant model, we have shown that mild GVHD can diminish the ability to respond to third party antigens expressed on activated DC vaccines. This suggests that the potency of GVT does not result from the alloreactive milieu, but rather from the nature of the antigens targeted. The mechanisms involved in the suppression of DC vaccine responses in allogeneic recipients are currently under study. These findings have important implications for the use of tumor antigen expressing vaccines as a modality to improve the graft versus tumor effect.

Development of a Cell Based Vaccine for the Immunotherapy of Acute and Chronic Leukemia by the Use of Autologous Dendritic Cells Loaded with Monoclonal Antibody Treated or Irradiated Leukemia Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4889-4889
Author(s):  
Caroline J. Duncan ◽  
Peter R.E. Johnson ◽  
Patrick H. Roddie
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Monoclonal Antibodies ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Subsets ◽  
Leukemia Cells ◽  
Cytotoxic T Cell ◽  
Dc Vaccine ◽  
Ctl Responses

Abstract Dendritic cell (DC) vaccines in leukemia show promise as a novel treatment modality however to date clinical evidence of efficacy has been limited. This is likely to be as a consequence of a combination of factors, which include insufficient immunogenicity of the DC vaccine and vaccination taking place in an environment adverse for generation of effective immune responses i.e. in patients with active disease. Our study aims to generate more efficient cytotoxic T cell (CTL) responses by improving DC uptake and presentation of leukemia cells in the remission state and will be applicable to both acute and chronic leukemias. Monoclonal antibodies (MoAbs) have been used to treat malignant cells prior to co-culture with DCs to enhance cross-presentation and generation of specific CTLs. We investigated whether this approach could improve DC induction of CTL responses in comparison to DCs loaded with UVB irradiated apoptotic leukemia cells. In this in vitro study we generated dendritic cells from adherent mononuclear cells (differentiation with GM-CSF and IL-4) of patients in remission following chemotherapy for acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL). The immature DCs were loaded with autologous leukemia cells from the patients’ presentation samples. The presentation leukemia cells were treated with either UVB irradiation or appropriate monoclonal antibodies (the anti-CD33 MoAb Mylotarg in AML and CML; the anti CD20 MoAb Rituximab or the anti-CD 52 MoAb Alemtuzumab in CLL). Apoptosis was assessed by Annexin/Propidium iodide labelling. Treatment of the leukemia cells by different MoAbs induced varying degrees of apoptosis. DC uptake of antibody treated or apoptotic leukemia cells was assessed by dual colour staining. Leukemia cells were stained with PKH and DCs labelled with FITC-CD80 or CD86. DC uptake was more efficient with MoAb treated cells irrespective of the degree of apoptosis induced by the MoAb. DCs were matured with TNFa for two days then co-cultured with autologous T cells for one week. T cell subsets and Regulatory T cells were assessed on the presentation and remission samples.The T cells were harvested and their cytoxicity assessed in an Interferon Gamma (IFNg) ELISPOT assay where the unmodified blasts were used as stimulators. Initial results show enhanced anti-leukemia activity in the MoAb treated group as compared to the irradiated group. A similar set up using allogeneic DCs and T cells confirmed the augmentation of CTL responses with MoAb treatment of leukemia cells.The use of MoAb in this setting shows promise for improvement in the success and applicability of DC vaccine strategies in leukemia.

Reinforcement of Cancer Immunotherapy by Adoptive Transfer of Cblb-Deficient Cytotoxic T Lymphocytes Combined with a Dendritic Cell Vaccine

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 957-957
Author(s):  
Christina Lutz-Nicoladoni ◽  
Patrizia Stoizner ◽  
Magdalena Pircher ◽  
Stephanie Wallner ◽  
Anna Maria Wolf ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Cancer Immunotherapy ◽  
Cytotoxic T Lymphocytes ◽  
Adoptive Transfer ◽  
Ex Vivo ◽  
Dc Vaccine

Abstract Abstract 957 Introduction: Various approaches to induce immunological rejection of tumors including transfer of autologous tumor infiltrating lymhocytes (TIL) after ex vivo clonal expansion or application of ex vivo transduced antigen specific T cell (TCR) transgenic T cells have been elaborated. In general, adoptive T cell transfer (ATC) has been combined with lympho-depleting agents (e.g. cyclophosphamide). However, the therapeutic efficacy of these cancer immunotherapy approaches is limited due to insufficient in vivo activation, expansion and survival of transferred effector immune cells, which is mainly due to suppressive mileu signals and immune evasion mechanisms induced by TGF-β. The E3 ubiquitin ligase Cbl-b is a key regulator of T cell activation and is assumed to confer TGF-β resistance. Thus we performed a proof-of-concept study evaluating Cbl-b targeting as “intracellular adjuvant” strategy to improve ATC for cancer immunotherapy. Material and Methods: We first tested the in vitro sensitivity of CTL towards TGF-β mediated immuno-suppressive cues and then in vivo evaluated the anti-tumor reactivity of cblb-deficient cytotoxic T lymphocytes (CTL) in murine tumor models alone or in combination with a dendritic cell (DC) vaccine. Results: Cblb-deficient CTL are hyper-responsive to TCR/CD28-stimulation in vitro and protected from the negative cues induced by TGF-β as determined by quantification fo IFN-g secretion and quantification of their proliferative capacity. Unexpectedly, adoptive transfer of polyclonal, non TCR-transgenic cblb-deficient CD8+ CTL, however, is not sufficient to reject B16ova or EG7 tumors in vivo, which is in clear contrast to previous reports using lymphopenic animals receiving adoptively transferred TCR-transgenic T cells. Thus, we next evaluated in vivo re-activation of adoptively transferred cblb-deficient T cells by a DC vaccine (i.e. SIINFEKL-pulsed DC). In strict contrast to ATC monotherapy, this approach now markedly delays tumor outgrowth and significantly increase survival rates, which is paralleled by an increased CTL infiltration rate to the tumor site and an enrichment of ova-specific and IFN-g-secreting CTL in the draining lymph nodes. Moreover, compared to wild-type CTL, cblb-deficient mice vaccinated with the DC vaccine show an increased cytolytic activity in vivo. Conclusions: In summary, we provide experimental evidence that genetic inactivation of cblb in polyclonal, non-TCR transgenic adoptively transferred CTL might serve as a novel “adjuvant approach”, suitable to augment the effectiveness of anti-cancer immunotherapies using ATC in immune-competent recipients. Disclosures: No relevant conflicts of interest to declare.

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