Stimulation of Anti-Tumor Immunity Using Dendritic Cells Transduced with Fowl Pox Vector Expressing MUC-1 and Costimulatory Molecules (PANVAC-F).

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5209-5209
Author(s):  
Baldev Vasir ◽  
Corrine Lenahan ◽  
Jacalyn Rosenblatt ◽  
Adam Bissonnette ◽  
Zekui Wu ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Tumor Immunity ◽  
Regulatory T Cell ◽  
Costimulatory Molecules ◽  
Cell Populations ◽  
Tumor Vaccines ◽  
Fluorescent Intensity ◽  
Stimulation Of

Abstract In pre-clinical models, vaccination with attenuated vaccinia and fowl pox virus expressing tumor antigens and costimulatory molecules (CD54/ICAM-1; CD58/LFA-1 and CD80/B7.1-TRICOM) potently stimulates anti-tumor immune responses. However, vaccine efficacy may be limited by intrinsic deficiencies of native dendritic cells (DC) populations in patients with malignancy that are required to process and present the virally introduced antigens. An alternative strategy involves the transduction of ex vivo generated activated DCs. We have examined the capacity of DCs transduced with a fowl pox vector expressing MUC-1, CEA, and TriCOM (PANVAC-F) to elicit antigen specific responses and expand activated as compared to regulatory T cell populations. Partially mature DCs were generated from leukopak preparations obtained from normal volunteers by culturing adherent peripheral blood mononuclear cells for 5 days with GM-CSF and IL-4. DCs were transduced with PANVAC-F vector and matured with either TNFa or the combination of PG-E2, TNFa, IL-6 and IL-1b. In 5 serial studies, transduction with PANVAC-F resulted in mean MUC1 expression in 64.6% (SEM: ±1.6) of cells with a mean fluorescent intensity (MFI) of 249.8 (SEM: ±45.7). In addition, transduced DCs also demonstrated high levels of expression of class II (99%; MFI:250), CD54 (98.4%;MFI:516), CD58 (98.8%;MFI:155) and CD80 (78.2%; MFI:115). Of note, transduced DCs demonstrated higher levels of the maturation marker CD83 (40.3%; SEM: ±1.6, n=3) as compared to untransduced DCs 19.7% (SEM: ±2.9) (p=0.02) suggesting that transduction enhanced DC maturation and activation. Transduced DCs matured with PGE2, TNFa, IL-6 and IL-1b as compared to TNFa alone demonstrated higher levels of CD83 and CCR7 and a more stable phenotype following withdrawal of cytokine support. To assess the ability of PANVAC-F to stimulate tumor antigen specific responses, the presence of T cells binding the MUC-1 specific tetramer was quantified following stimulation of autologous T cells derived from HLA*0201 healthy donors. An increase in CD8+ and MUC1+ cells were observed (8.3%) with stimulation with PANVAC-F transduced DCs as compared to untransduced DCs (2.5%). The capacity of DCs transduced with PANVAC-F to stimulate interferon gamma producing activated T cells, as compared to CD4+/CD25+/Foxp3+ regulatory T cell populations is being assessed. In summary, PANVAC-F transduced DCs stimulate expansion of antigen specific T cell populations suggesting their potential role as tumor vaccines for MUC-1/CEA expressing tumors. We are initiating a trial for patients with ovarian carcinoma in early (marker only) relapse in which patients will be randomized to undergo serial vaccination with PANVAC-V/PANVAC-F or DCs transduced with PANVAC-F. The capacity to generate anti-tumor immunity in vivo will be assessed as a primary endpoint.

Leukemia Derived Dendritic Cells (LDCs) Are Functionally Deficient and Inferior to DC/Leukemia Fusion Cells as a Tumor Vaccine for AML.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2788-2788
Author(s):  
Jacalyn Rosenblatt ◽  
Richard Stone ◽  
Corrine Lenahan ◽  
Zekwui Wu ◽  
Baldev Vasir ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Interferon Gamma ◽  
Tumor Immunity ◽  
Peripheral Blood ◽  
Tumor Antigens ◽  
Tumor Vaccine ◽  
Costimulatory Molecules ◽  
Leukemia Cells

Abstract We have previously demonstrated that dendritic cells (DCs) fused with malignant cells stimulate anti-tumor immunity by presenting a braod array of tumor antigens in the context of DC mediated costimulation. DCs differentiated from leukemia cells (LDCs) are also being explored as cancer vaccines in which leukemia associated antigens are presented. We examined the phenotypic and functional characteristics of DC/Leukemia fusions and LDCs to assess their potential as tumor vaccines. Leukemia blasts were isolated from peripheral blood of patients with AML. CD34 selection was performed on a subset of samples by magnetic bead separation. LDCs were generated by culturing blasts in the presence of GM-CSF, IL-4 and TNFα for 7 days. Alternatively, leukemia cells were fused with DC by coculture in the presence of polyethylene glycol. Differentiation of leukemic blasts into LDCs resulted in increased expression of HLA-DR and CD 11c. Unlike normal peripheral blood mononuclear cells, differentiation of leukemic blasts resulted in only modest expression of the costimulatory molecules, CD80 and CD86 (mean expression 12% and 30%) and no increase in expression of the maturation marker, CD83 (mean expression 4%). In addition, expression of the leukemia associated antigen c-kit (CD117) was lower on LDCs than on blasts (mean expression 34% on blasts, 15% on LDCs). To assess the capacity of the primitive leukemia clonal population to differentiate into DCs, CD34+ cells were isolated from the blast population and assessed after cytokine differentiation. Cytokine differentiation did not result in upregulation of CD80, CD83, or CD86 expression in the CD34+ population (mean expression 5%, 2%, 17%). In contrast, differentiation of the CD34- population resulted in moderate expression of CD80, CD83 and CD86 (mean expression 15%, 14%, 48%). In contrast to LDCs which do not strongly express co-stimulatory molecules and lose expression of leukemia associated antigens, fusion cells expressed both DC and tumor associated antigens (mean fusion efficiency 27%). The functional characteristics of DC derived from leukemic blasts were examined. Allogeneic T cell proliferation in response to stimulation by LDCs was not significantly higher than after stimulation with undifferentiated blasts (ratio 10:1, mean SI 17% with LDCs vs 9% with undifferentiated blasts, p=0.19). Neither stimulation with blasts nor with LDCs induced T cell production of interferon gamma. In contrast, interferon gamma production by T cells in response to stimulation with fusion cells was higher than after stimulation with undifferentiated blasts. In summary, LDCs do not demonstrate normal upregulation of costimulatory molecules, and lose expression of tumor antigens. In contrast, DC/leukemia fusions coexpress tumor and DC associated markers. While LDCs stimulate interferon gamma production by T cells poorly, fusion cells more potently stimulate interferon gamma production by allogeneic T cells than do undifferentiated blasts. This suggests that LDC may be ineffective as a tumor vaccine in AML, and that fusion cells may be superior to LDC in generating effective anti-tumor immune responses. Strategies to enhance the ability of both LDC and of fusion cells to stimulate anti-tumor immunity are being explored.

538 Harnessing cross-dressing dendritic cells to strengthen anti-tumor immunity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A574-A574
Author(s):  
Ellen Duong ◽  
Timothy Fessenden ◽  
Arjun Bhutkar ◽  
Stefani Spranger
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cancer Cell ◽  
Tumor Immunity ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Cell Responses ◽  
Cell Immunity ◽  
Cross Dressing

BackgroundCytotoxic (CD8+) T-cells are required for tumor eradication and durable anti-tumor immunity.1 The induction of tumor-reactive CD8+ T-cells is predominately attributed to a subset of dendritic cells (DC) called Batf3-driven DC1, given their robust ability to cross-present antigens for T-cell priming and their role in effector T-cell recruitment.2–4 Presence of the DC1 signature in tumors correlates with improved survival and response to immunotherapies.5–7 Yet, most tumors with a DC1 infiltrate still progress, suggesting that while DC1 can initiate tumor-reactive CD8+ T-cell responses, they are unable to sustain them. Therefore, there is a critical need to identify and engage additional stimulatory DC subsets to strengthen anti-tumor immunity and boost immunotherapy responses.MethodsTo identify DC subsets that drive poly-functional CD8+ T-cell responses, we compared the DC infiltrate of a spontaneously regressing tumor with a progressing tumor. Multicolor flow immunophenotyping and single-cell RNA-sequencing were used to profile the DC compartment of both tumors. IFNγ-ELISpot was performed on splenocytes to assess for systemic tumor-reactive T-cell responses. Sorted DC subsets from tumors were co-cultured with TCR-transgenic T-cells ex vivo to evaluate their stimulatory capacity. Cross-dressing (in vivo/ex vivo) was assayed by staining for transfer of tumor-derived H-2b MHC complexes to Balb/c DC, which express the H-2d haplotype. Protective systemic immunity was assayed via contralateral flank tumor outgrowth experiments.ResultsRegressor tumors were infiltrated with more cross-presenting DC1 than progressor tumors. However, tumor-reactive CD8+ T-cell responses and tumor control were preserved in Batf3-/- mice lacking DC1, indicating that anti-tumor immune responses could be induced independent of DC1. Through functional assays, we established that anti-tumor immunity against regressor tumors required CD11c+ DC and cGAS/STING-independent type-I-interferon-sensing. Single-cell RNA-sequencing of the immune infiltrate of regressor tumors revealed a novel CD11b+ DC subset expressing an interferon-stimulated gene signature (ISG+ DC). Flow studies demonstrated that ISG+ DC were more enriched in regressor tumors than progressor tumors. We showed that ISG+ DC could activate CD8+ T-cells by cross-dressing with tumor-derived peptide-MHC complexes, thereby bypassing the requirement for cross-presentation to initiate CD8+ T-cell-driven immunity. ISG+ DC highly expressed cytosolic dsRNA sensors (RIG-I/MDA5) and could be therapeutically harnessed by exogenous addition of a dsRNA analog to drive protective CD8+ T-cell responses in DC1-deficient mice.ConclusionsThe DC infiltrate in tumors can dictate the strength of anti-tumor immunity. Harnessing multiple stimulatory DC subsets, such as cross-presenting DC1 and cross-dressing ISG+ DC, provides a therapeutic opportunity to enhance anti-tumor immunity and increase immunotherapy responses.ReferencesFridman WH, et al. The immune contexture in human tumours: impact on clinical outcome. Nature Reviews Cancer 2012;12(4): p. 298–306.Hildner K, et al. Batf3 deficiency reveals a critical role for CD8alpha+ dendritic cells in cytotoxic T cell immunity. Science 2008;322(5904):p. 1097–100.Spranger S, et al. Tumor-Residing Batf3 dendritic cells are required for effector T cell trafficking and adoptive T cell therapy. Cancer Cell 2017;31(5):p. 711–723.e4.Roberts, EW, et al., Critical role for CD103(+)/CD141(+) dendritic cells bearing CCR7 for tumor antigen trafficking and priming of T cell immunity in melanoma. Cancer Cell 2016;30(2): p. 324–336.Broz ML, et al. Dissecting the tumor myeloid compartment reveals rare activating antigen-presenting cells critical for T cell immunity. Cancer Cell 2014;26(5): p. 638–52.Salmon H., et al., Expansion and activation of CD103(+) dendritic cell progenitors at the tumor site enhances tumor responses to therapeutic PD-L1 and BRAF inhibition. Immunity, 2016. 44(4): p. 924–38.Sánchez-Paulete AR, et al., Cancer immunotherapy with immunomodulatory anti-CD137 and Anti-PD-1 monoclonal antibodies requires BATF3-dependent dendritic cells. Cancer Discov, 2016;6(1):p. 71–9.

Stimulation of autologous proliferative and cytotoxic T-cell responses by “leukemic dendritic cells” derived from blast cells in acute myeloid leukemia

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2764-2771 ◽  
Author(s):  
Beth D. Harrison ◽  
Julie A. Adams ◽  
Mark Briggs ◽  
Michelle L. Brereton ◽  
John A. Liu Yin
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Dendritic Cells ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Responses ◽  
Cell Responses ◽  
Antigen Presenting ◽  
Acute Myeloid ◽  
Stimulation Of

Abstract Effective presentation of tumor antigens is fundamental to strategies aimed at enrolling the immune system in eradication of residual disease after conventional treatments. Myeloid malignancies provide a unique opportunity to derive dendritic cells (DCs), functioning antigen-presenting cells, from the malignant cells themselves. These may then co-express leukemic antigens together with appropriate secondary signals and be used to generate a specific, antileukemic immune response. In this study, blasts from 40 patients with acute myeloid leukemia (AML) were cultured with combinations of granulocyte-macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor α, and development to DCs was assessed. After culture, cells from 24 samples exhibited morphological and immunophenotypic features of DCs, including expression of major histocompatibility complex class II, CD1a, CD83, and CD86, and were potent stimulators in an allogeneic mixed lymphocyte reaction (MLR). Stimulation of autologous T-cell responses was assessed by the proliferative response of autologous T cells to the leukemic DCs and by demonstration of the induction of specific, autologous, antileukemic cytotoxicity. Of 17 samples, 11 were effective stimulators in the autologous MLR, and low, but consistent, autologous, antileukemic cytotoxicity was induced in 8 of 11 cases (mean, 27%; range, 17%-37%). This study indicates that cells with enhanced antigen-presenting ability can be generated from AML blasts, that these cells can effectively prime autologous cytotoxic T cells in vitro, and that they may be used as potential vaccines in the immunotherapy of AML.

scholarly journals Restricted Clonal Expression of IL-2 By Naive T Cells Reflects Differential Dynamic Interactions with Dendritic Cells

2003 ◽  
Vol 198 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Vincent Hurez ◽  
Arman Saparov ◽  
Albert Tousson ◽  
Michael J. Fuller ◽  
Takekazu Kubo ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Gene Transcription ◽  
Cell Populations ◽  
Intrinsic Variability ◽  
Dynamic Interactions ◽  
Transgenic Model ◽  
Transient Interactions

Limited frequencies of T cells express IL-2 in primary antigenic responses, despite activation marker expression and proliferation by most clonal members. To define the basis for restricted IL-2 expression, a videomicroscopic system and IL-2 reporter transgenic model were used to characterize dendritic cell (DC)–T cell interactions. T cells destined to produce IL-2 required prolonged interactions with DCs, whereas most T cells established only transient interactions with DCs and were activated, but did not express IL-2. Extended conjugation of T cells with DCs was not always sufficient to initiate IL-2 expression. Thus, there is intrinsic variability in clonal T cell populations that restricts IL-2 commitment, and prolonged engagement with mature DCs is necessary, but not sufficient, for IL-2 gene transcription.

scholarly journals Induction of Interleukin 10–Producing, Nonproliferating Cd4+ T Cells with Regulatory Properties by Repetitive Stimulation with Allogeneic Immature Human Dendritic Cells

2000 ◽  
Vol 192 (9) ◽  
pp. 1213-1222 ◽  
Author(s):  
Helmut Jonuleit ◽  
Edgar Schmitt ◽  
Gerold Schuler ◽  
Jürgen Knop ◽  
Alexander H. Enk
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Mononuclear Cells ◽  
Repetitive Stimulation ◽  
Negative Regulator ◽  
Th1 Cells ◽  
Alloreactive T Cells ◽  
Stimulation Of

The functional properties of dendritic cells (DCs) are strictly dependent on their maturational state. To analyze the influence of the maturational state of DCs on priming and differentiation of T cells, immature CD83− and mature CD83+ human DCs were used for stimulation of naive, allogeneic CD4+ T cells. Repetitive stimulation with mature DCs resulted in a strong expansion of alloreactive T cells and the exclusive development of T helper type 1 (Th1) cells. In contrast, after repetitive stimulation with immature DCs the alloreactive T cells showed an irreversibly inhibited proliferation that could not be restored by restimulation with mature DCs or peripheral blood mononuclear cells, or by the addition of interleukin (IL)-2. Only stimulation of T cells with mature DCs resulted in an upregulation of CD154, CD69, and CD70, whereas T cells activated with immature DCs showed an early upregulation of the negative regulator cytotoxic T lymphocyte–associated molecule 4 (CTLA-4). These T cells lost their ability to produce interferon γ, IL-2, or IL-4 after several stimulations with immature DCs and differentiated into nonproliferating, IL-10–producing T cells. Furthermore, in coculture experiments these T cells inhibited the antigen-driven proliferation of Th1 cells in a contact- and dose-dependent, but antigen-nonspecific manner. These data show that immature and mature DCs induce different types of T cell responses: inflammatory Th1 cells are induced by mature DCs, and IL-10–producing T cell regulatory 1–like cells by immature DCs.

Generation of Leukemia-Derived Dendritic Cells (DCleu) as a Basis for Specific Immunotherapy in Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2547-2547
Author(s):  
Helga Schmetzer ◽  
Christoph Schmid ◽  
Susanne Kufner ◽  
Renate Pelka-Fleischer ◽  
Tanja Kroell ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cell Response ◽  
T Cell Response ◽  
Aberrant Expression ◽  
Immune Phenotype ◽  
Cytogenetic Aberrations ◽  
Stimulation Of

Abstract The presentation of leukemic antigens can be improved in AML and MDS by in vitro generation of dendritic cells of leukemic origin (DCleu), thereby creating a platform for the generation of leukemia-specific cytotoxic lymphocytes (CTL). To further investigate this approach, we developed a serum-free culture system using MCM-Mimic medium (X-vivo + GM-GSF + IL-4 + FL + IL1β + IL-6 + TNFα + PGE2) for differentiation of malignant myeloid blasts to DCleu. Periperal blood mononuclear cells (PB-MNC) were obtained from 100 AML and 55 MDS-patients. Samples contained a mean of 59%/and 6% of blasts, respectively. After 14 days, cultures contained on average 34% (AML) and 20%(MDS) DC. DC yields were best in monocytic subtypes (AML M4, M5 and CMML). Cytogenetic aberrations of the leukemia had no influence. The leukemic origin of cultured DC was demonstrated using a acombined FISH/immune phenotyping assay (FISH/IPA): In cells showing a characteristic DC morphology and immune phenotype, FISH was used to detect specific cytogenetic aberrations identified in the leukemic population at time of diagnosis. Alternativly, DCleu were identified by detecting coexpression of DC markers and a leukemia-specific immune phenotype (as defined by aberrant expression of lineage markers or a characteristic CD34+/CD117+ phenotype in MDS). However, in most cases not all leukemic blasts in a given sample could be differentiated, since on average 47% of clonal cells did not acquire a DC-like immunophenotype. Vice versa, not all DC identified at the end of the culture period were DCleu. The capacity of DCleu to elicit a specific T-cell response was demonstrated by upregulation of contact-molecules, responsible for DC/T-cell contact, by DC-activated T-cell proliferation and by the capacity of DC-activated T-cells to specifically lyse naive blasts. In 6%/31% of AML/MDS-cases, <10% DC could be generated. Therefore, other DC-culture-assays were compared with respect to DC harvest, to identify the best method for DC-generation in each individual patient. Compared to `MCM-Mimic`, harvest of DC could be improved by `CA-Ionophore-media`(A23187 + Il4) in 4 of 7 cases, whereas in 3 cases, MCM led to higher DC-yields. In conclusion, DCleu can be generated in the majority of patients with AML and MDS. To optimize DC harvest for in vitro and in vivo use, different culture assays should be compared in each individual case. DCleu are able to elicit a specific T-cell response in vitro. Nevertheless, cultures containing DCleu also contain relevant numbers of undifferentiated blasts and DC of non-leukemic origin. These cells may represent an obstacle for the clinical use of DCleu, since they may cause specific anergy or unspecific stimulation of effector T-cells. Improvement of culture conditions for generation of DCleu, and methods to separate DCleu before stimulation of effector cells will be required, before clinical trials are feasible.

Transduction of Malignant Plasma Cells with Three Costimulatory Molecules (TRICOM) Elicits Myeloma-Specific Immune Response in Vitro – a Promising Strategy for Immunotherapy

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1908-1908
Author(s):  
Katarina Luptakova ◽  
Heidi Mills ◽  
Jacalyn Rosenblatt ◽  
Dina Stroopinsky ◽  
Turner Kufe ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Plasma Cells ◽  
Costimulatory Molecules ◽  
Cell Populations ◽  
Autologous Tumor

Abstract Abstract 1908 Introduction: Tumor vaccines hold promise as a means of eliciting anti-myeloma immunity and controlling disease that may be resistant to chemotherapy and biologic therapy. We have developed a whole cell tumor vaccine, whereby patient derived plasma cells are transduced with an attenuated vaccinia vector that contains transgenes for the costimulatory molecules B7.1 (CD80), ICAM-1 (CD54), and LFA-3 (CD58), designated TRIad of COstimulatory Molecules (TRICOM). In this manner, a broad array of tumor antigens, including those which may be specific to a given patient, are presented in the context of costimulatory molecules that have been shown to be synergistic in the stimulation of the effector T-cells. In the present study, we evaluated the phenotype and functional characteristics of TRICOM transduced primary myeloma cells. Methods and results: Plasma cells were isolated from bone marrow aspirates obtained from patients with multiple myeloma following Ficoll density centrifugation. Bone marrow derived mononuclear cells were infected with a replication-defective poxviral vector, the modified vaccinia Ankara strain (MVA), encoding TRICOM, or a control empty MVA vector. The expression of costimulatory molecules was assessed using flow cytometric analysis 3 hrs following viral infection. Viral transduction using the TRICOM vector at the dose of 20 MOI (multiplicity of infection) increased the mean percentage of CD38+ cells expressing CD80, CD54 and CD58 from a minimal baseline level (below 5%) to 70%, 56% and 47%, respectively (n=4). Transduction with control MVA vector did not augment expression of costimulatory molecules on plasma cells (mean percent expression of CD80, CD54 and CD58 of 2.6%, 2.7% and 3.8%, respectively, n=4). Of note, compared to CD38+ plasma cells, the CD38 negative fraction of bone marrow derived mononuclear cells demonstrated a significantly lower TRICOM transduction efficiency (mean percent expression of CD80, CD54 and CD58 of 16%, 17% and 16%, respectively, n=4, p<0.05 compared to CD38+ plasma cells). The ability of MVA-TRICOM transduced plasma cells to stimulate autologous T cell populations in vitro was assessed. Patient derived T-cells were purified from the non-adherent portion of PBMC by magnetic bead separation. MVA-TRICOM or empty MVA vector infected plasma cells were irradiated with 20Gy and co-cultured with autologous T cells at a 10:1 ratio of effector cells to vaccine for 7 days. MVA-TRICOM transduced plasma cells potently stimulated activated T cell responses, as assessed by the percentage of CD4+/CD25+/CD69+ T-cells (mean 7.8% of activated T-cells with TRICOM vaccine vs. 2.7% with control vaccine, n=3, p<0.05). In contrast, vaccine stimulation did not result in regulatory T-cell expansion, assessed as the percentage of cells co-expressing CD4,CD25 and FoxP3 (2.4% vs. 2.3%, for TRICOM and control vaccine, respectively, n=3). In concert with these findings, vaccine stimulation resulted in a polarization towards Th1 cytokine secretion, with 7.9% of CD4+ T-cells expressing intracellular IFN-γ after stimulation with TRICOM vaccine as compared to 5.4% after stimulation with the control vaccine (n=3, p<0.05). To further assess the expansion of tumor specific T cell populations, the ability of vaccine stimulated T cells to kill autologous tumor was assessed in a cell-based fluorogenic cytotoxicity assay. MVA-TRICOM transduced plasma cells potently stimulate the expansion of myeloma specific CTLs with the capacity to lyse autologous tumor targets. Mean CTL lysis was 20% and 8% for vaccine stimulated and unstimulated T cells respectively (n=2). Conclusions: Malignant plasma cells transduced with MVA-TRICOM strongly express costimulatory molecules, and potently stimulate activated, tumor reactive T cell populations. This preclinical data serves as a platform for developing a phase 1 clinical trial evaluating the use of MVA-TRICOM transduced autologous plasma cells in patients with multiple myeloma. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Effector T Cells Boost Regulatory T Cell Expansion by IL-2, TNF, OX40, and Plasmacytoid Dendritic Cells Depending on the Immune Context

2014 ◽  
Vol 194 (3) ◽  
pp. 999-1010 ◽  
Author(s):  
Audrey Baeyens ◽  
David Saadoun ◽  
Fabienne Billiard ◽  
Angéline Rouers ◽  
Sylvie Grégoire ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Regulatory T Cell ◽  
Cell Expansion ◽  
Plasmacytoid Dendritic Cells ◽  
Effector T Cells ◽  
T Cell Expansion
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