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.

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.

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.

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.

Clinical Trial Evaluating DC/AML Fusion Cell Vaccination Alone and in Conjunction with PD-1 Blockade in AML Patients Who Achieve a Chemotherapy-Induced Remission

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 948-948 ◽  
Author(s):  
Jacalyn Rosenblatt ◽  
Richard M. Stone ◽  
Irit Avivi ◽  
Lynne Uhl ◽  
Donna Neuberg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
Induction Chemotherapy ◽  
Peripheral Blood ◽  
Allogeneic Transplantation ◽  
Leukemia Cells ◽  
Vaccine Site ◽  
Fusion Cell ◽  
The Mean

Abstract Abstract 948 Patients with acute myeloid leukemia (AML) achieve remission following chemotherapy; however, curative outcomes remain elusive due to relapse with chemotherapy-resistant disease. Allogeneic transplantation remains a potentially curative therapy for AML patients, but is associated with significant morbidity and mortality due to the lack of specificity of the alloreactive response. A promising area of investigation is the development of cancer vaccines that educate host immunity to more selectively target leukemia cells, including the stem cell compartment. Our group has developed a cancer vaccine model in which dendritic cells (DCs) are fused to autologous tumor cells, resulting in the presentation of multiple tumor antigens with the capacity to elicit a broad anti-tumor response. A fundamental challenge to developing a more effective tumor vaccine is overcoming the immunosuppressive milieu by which tumor cells evade host immunity. Key elements contributing to tumor-mediated immune suppression are the increased presence of regulatory T cells in patients with malignancy, and upregulation of the PD-1/PDL1 pathway. Tumor expression of PD-L1 promotes T cell tolerance by binding PD-1 on activated T cells and suppressing their capacity to secrete stimulatory cytokines. In addition, the PD-1/PDL-1 pathway has been shown to inhibit T cell-mediated lysis of tumor cells, potentially preventing a clinically meaningful immunologic response to vaccination. We are conducting a clinical trial in which AML patients who are in a first or second complete remission following chemotherapy receive three monthly doses of DC/AML fusion cells alone (Cohort 1) or in conjunction with anti-PD1 antibody, CT-011 (cohort 2). To date, 16 patients (9 males, 7 females; mean age 55 years) have been enrolled to the first cohort. All patients underwent successful tumor collection from either a bone marrow aspirate (N=12), collection of 20 cc of peripheral blood (N=3), or leukapheresis product (N=1) at the time of presentation with newly diagnosed AML (N=15) or first relapsed AML (N=1). The mean yield was 1.45×108 cells, and the mean viability was 90%. Tumor cells were subjected to immunohistochemical analysis to identify antigens unique to the leukemia fusion partner. Those patients achieving complete remission following 1–2 cycles of induction chemotherapy underwent leukapheresis for dendritic cell generation. Adherent peripheral blood mononuclear cells were isolated, cultured in the presence of GM-CSF and IL-4 for 5–7 days, and then exposed to TNFα for 48–72 hours to generate mature DCs. Mean viability of the DC preparation was 92%. DCs strongly expressed the co-stimulatory molecule CD86 (mean 75% expression). One patient died during remission induction chemotherapy and 3 patients were removed from study after induction chemotherapy to undergo allogeneic transplantation. Vaccine was successfully generated in 9 patients at a dose of 5×106 fusions cells, mean fusion efficiency of 30%, and viability of 87%. As a measure of their activity as antigen presenting cells, the capacity of the fusion cell preparation to stimulate allogeneic T cell proliferation ex vivo was quantified. In contrast to the leukemia preparation (mean stimulation index (SI) 3.7), the DC and fusion cell preparation were potent stimulators (mean SI 20.8 and 13.1, respectively). Vaccination with the DC/leukemia fusion vaccine was initiated within 12 weeks from count recovery following their final cycle of chemotherapy. 4 patients have completed vaccinations and are 2, 4, 5 and 6 months following the final vaccine. One patient was taken off study for disease progression one week after receiving his first vaccine. 4 patients experienced grade 1 vaccine site reactions. Biopsy of a vaccine site reaction demonstrated a dense T cell infiltrate. Additional vaccine related adverse events have included grade 1 ankle pain and edema. The remaining patients are undergoing chemotherapy, and when complete, will initiate vaccination. Peripheral blood samples are being collected prior to each vaccination and at 1, 3, and 6 months following completion of vaccination. Immune response targeting leukemia cells, leukemic stem cells, and leukemia associated antigens will be assessed. Levels of circulating regulatory T cells and T cell expression of PD1 will be measured. Time to disease progression will also be determined. Disclosures: Avigan: Curetech: Research Funding.

Leukemic blasts fail to differentiate into mature antigen presenting cells, and may hinder dendritic cell maturation in vitro and in vivo

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 10556-10556
Author(s):  
J. Rosenblatt ◽  
R. Stone ◽  
C. Lenahan ◽  
Z. Wu ◽  
B. Vasir ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Tumor Vaccine ◽  
Leukemia Cells ◽  
Phenotypic Characteristics ◽  
Gm Csf ◽  
Maturation In Vitro ◽  
Dc Maturation

10556 Background: Dendritic cells (DC) play a key role in the development of tumor specific immune responses. Dendritic cells differentiated from leukemic blasts (LDC) are being explored as a tumor vaccine in AML. We examined the phenotypic and functional characteristics of LDC, the phenotypic characteristics of native DC in AML patients, and the effect of leukemic blasts on the phenotype of DC generated from normal donors. Methods: Leukemia blasts were isolated from peripheral blood of 24 patients with AML. LDC were generated by culturing blasts in the presence of GM-CSF, IL-4 and TNFa for 7 days. The phenotype of circulating DC1 (CD11C+/lin-) and DC2 (CD123+/ lin-) in AML patients was assessed by multichannel FACS analysis. To assess the effect of blasts on DC maturation, adherent mononuclear cells were isolated from normal donors, combined with leukemia cells in a 10:1 ratio, and cultured with GM-CSF, IL-4, and TNFa. Results: LDC demonstrate only modest expression of the costimulatory molecules CD80 and CD86 (mean expression 10% and 32%) and poorly express the maturation marker CD83 (mean expression 4%). Interferon gamma production by autologous T cells was not higher after stimulation with LDC than with blasts. LDC stimlation resulted in a 2 fold increase in both CD4+/CD25+/CD69+ (activated) and CD4+/CD25+/FOXP3+ (regulatory) T cells. Given the inability of leukemia progenitors to differentiate into phenotypically mature DC, we assessed whether leukemia cells directly inhibit differentiation of DC from normal progenitors. Expression of costimulatory molecules was decreased in DC differentiated in the presence of blasts. Mean expression of CD80, CD83, and CD86 was 16%, 2%, 83% and 49%, 10%, 99% for DCs generated in the presence or absence blasts respectively. Phenotypic characteristics of native DC in patients with AML were examined. In 3 experiments, a predominance of DC2 was seen (ratio DC2/DC1 5), and both DC1 and DC2 poorly expressed CD83 (mean expression 9% DC1, 0.9% DC2). Conclusions: LDC have phenotypic and functional deficiencies, limiting their efficacy as a tumor vaccine. Contact with leukemic blasts may inhibit DC maturation in vitro and in vivo, which may contribute to the lack of effective antitumor immunity in AML patients. No significant financial relationships to disclose.

Tumor-derived activated cells: preliminary laboratory and clinical results.

1989 ◽  
Vol 35 (8) ◽  
pp. 1576-1580 ◽  
Author(s):  
R K Oldham ◽  
J R Maleckar ◽  
C S Friddell ◽  
W M Lewko ◽  
W H West ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
Peripheral Blood ◽  
Tumor Antigens ◽  
Interleukin 2 ◽  
Limiting Factors ◽  
Limiting Factor ◽  
Clinical Effects ◽  
Lymphokine Activated Killer Cells

Abstract It is well known that T lymphocytes can mediate significant anti-tumor responses. A limiting factor has always been the ability to expand T cells, whether from the peripheral blood, spleen, or tumor. The recent availability of recombinant interleukin-2 (r-IL2) has demonstrated the feasibility of expanding T cells and the clinical efficacy of these cells as anti-tumor effectors in murine models. Concomitantly, researchers discovered that lymphokine-activated killer cells--peripheral blood cells functionally distinct from T cells--could be cultured, expanded, and re-infused in patients, with significant clinical effects. For many years, the infiltrating lymphocytes have been recognized in tumor biopsies and known to be cytolytically active. Major limiting factors were the ability to culture large numbers of these infiltrating cells and the limited understanding of the tumor antigens involved for T-cell stimulation. Restimulation by antigen (tumor cells) appears to provide the ongoing antigen stimulation needed to maintain selective killing of tumor cells. By defining various factors in the medium that support and enhance T-cell growth and activation, the components are becoming available to develop a broad attack on advanced cancer by using this laboratory-based technology of stimulation and expansion of tumor-derived activated cells.

Induction of Potentially Protective HIV-Specific T-Cell Responses In Vitro by Gag mRNA-Electroporated Dendritic Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1261-1261
Author(s):  
Zwi N. Berneman ◽  
Ellen R. Van Gulck ◽  
Leo Heyndrickx ◽  
Peter Ponsaerts ◽  
Viggo F.I. Van Tendeloo ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cell Count ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
T Cell Responses ◽  
Ifn Gamma ◽  
Cell Responses ◽  
Hiv 1

Abstract Human immunodeficiency virus type 1 (HIV-1) infection is characterized by dysfunction of HIV-1-specific T-lymphocytes. In order to suppress the virus and delay evolution to AIDS, antigen-loaded antigen-presenting cells, including dendritic cells (DC) might be useful to boost and broaden HIV-1-specific T-cell responses. Monocyte-derived DC from 15 untreated (“naive”) and 15 highly active anti-retroviral therapy (HAART)-treated HIV-1-infected patients were electroporated with codon-optimized (“humanized”) mRNA encoding consensus HxB-2 (hHxB-2) Gag protein. These DC were co-cultured for 1 week with autologous peripheral blood leucocytes (PBL). Potential expansion of specific T-cells was measured by comparing ELISPOT responses of PBL before and after co-culture, using a pool of overlapping peptides, spanning the HxB-2 Gag. Expansion of specific PBL after co-culture was noted for T cells producing interferon (IFN)-gamma, interleukin (IL)-2 and perforin (Wilcoxon signed rank test p<0.05, except for IL-2 in naive patients). From all HIV-1-seropositive persons tested, 12 HAART-treated and 12 naive patients match in absolute number of CD4+ T-cells. A comparison of the increase of the response between day 0 and after 1 week of stimulation between those two groups showed that the response was higher in HAART-treated subjects for IFN-gamma and IL-2 but not for perforin in comparison to untreated subjects. Examining purified CD4+ and CD8+ T-cells after co-culture revealed that HxB-2 Gag peptides induced IFN-gamma in both subsets, that IL-2 was only secreted by CD4+ T-cells and that perforin was dominantly secreted by CD8+ T-cells. Remarkably, the perforin response in the treatment-naive persons was negatively correlated with the peripheral blood absolute CD4+ and CD8+ T-cell count (respectively R=0.618, p=0.014; and R=0.529, p=0.043). Furthermore, the nadir absolute CD4+ T-cell count in HAART-treated subjects was positively correlated with the IL-2 response (R=0.521, p=0.046) and negatively correlated with the perforin response (R=0.588, p=0.021). In conclusion, DC from HAART-treated and therapy-naive subjects, electroporated with hHxB-2 gag mRNA have the capacity to induce secondary T-cell responses. In an earlier study (Van Gulck ER et al. Blood2006;107:1818–1827), we already demonstrated ex vivo that CD4+ and CD8+ T-cells from non-treated HIV-1-infected subjects can be directly triggered by DC electroporated with autologous proviral-derived gag mRNA. Taken together, our results open the perspective for a DC immunotherapy for HIV disease.

scholarly journals Inducing Tumor Immunity through the Selective Engagement of Activating Fcγ Receptors on Dendritic Cells

2002 ◽  
Vol 195 (12) ◽  
pp. 1653-1659 ◽  
Author(s):  
Alexis M. Kalergis ◽  
Jeffrey V. Ravetch
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Protective Immunity ◽  
Cell Activation ◽  
Tumor Antigens ◽  
Ex Vivo ◽  
Tumor Vaccines ◽  
Antigen Capture

Induction of tumor-specific immunity requires that dendritic cells (DCs) efficiently capture and present tumor antigens to result in the expansion and activation of tumor-specific cytotoxic T cells. The transition from antigen capture to T cell stimulation requires a maturation signal; in its absence tolerance, rather than immunity may develop. While immune complexes (ICs) are able to enhance antigen capture, they can be poor at inducing DC maturation, naive T cell activation and protective immunity. We now demonstrate that interfering with the inhibitory signal delivered by FcγRIIB on DCs converts ICs to potent maturation agents and results in T cell activation. Applying this approach to immunization with DCs pulsed ex-vivo with ICs, we have generated antigen-specific CD8+ T cells in vivo and achieved efficient protective immunity in a murine melanoma model. These data imply that ICs may normally function to maintain tolerance through the binding to inhibitory FcγRs on DCs, but they can be converted to potent immunogenic stimuli by selective engagement of activating FcγRs. This mechanism suggests a novel approach to the development of tumor vaccines.

scholarly journals AB0018 ACCUMULATION OF FUNCTIONALLY MATURE CD1C+ DENDRITIC CELLS CONTRIBUTES TO SYNOVIAL INFLAMMATION IN INFLAMMATORY ARTHRITIS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1043.2-1043
Author(s):  
M. Canavan ◽  
V. Marzaioli ◽  
V. Bhargava ◽  
S. Nagpal ◽  
P. Gallagher ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Synovial Fluid ◽  
Research And Development ◽  
Rna Sequencing ◽  
Synovial Tissue ◽  
Peripheral Blood ◽  
Synovial Inflammation ◽  
Research Support

Background:Myeloid Dendritic Cells (DC) are potent antigen presenting cells that can be subdivided into CD141 and CD1c+ DC. We have previously reported an unacknowledged role for CD141+DC in the IA synovium. However, the identification and function of CD1c+ DC in the IA synovium has yet to be fully elucidated.Objectives:To investigate if CD1c+DC reside in the IA synovium and ascertain if they represent a unique population, distinct from peripheral CD1c+DC and if they contribute to synovial inflammation.Methods:Synovial tissue (ST) biopsies and synovial fluid mononuclear cells (SFMC) were obtained via arthroscopy and healthy control (HC) ST was obtained during ACL surgery. Synovial tissue single cells suspensions were generated following enzymatic and mechanical digestion. Single cell analysis of synovial tissue cell suspensions, along with PBMC and SFMC was performed by multicolour flow cytometry. CD1c+DC were sorted from IA synovial fluid and peripheral blood and bulk RNA sequencing was performed. CD1c+DC functionality and maturation was assessed using OVA DQ phagocytosis assays, multiplex ELISA and DC: T cell cocultures.Results:Within the circulation the frequency of CD1c+DC are significantly decreased in IA peripheral blood compared to HC (p<0.01) in addition to expressing significantly higher levels of the maturation markers CD80 (p<0.01) and CD40 (p=0.08). IA peripheral blood DC also express significantly higher levels of CXCR3 (p<0.01) and CCR7 (p<0.05) compared to HC - suggestive of DC migration from the periphery to the synovium. Following RNA-seq analysis, IPA and differentially expressed gene (DEG) analysis revealed an enrichment in genes involved in DC maturation, TLR signalling and chemokine signalling in IA peripheral blood compared to HC. In support of the hypothesis that DC migrate and accumulate in the IA synovium, CD1c+ DC were identified in IA ST and were significantly enriched compared to IA peripheral blood (p<0.01). IA ST CD1c+DC express significantly higher levels of the activation marker CD80 compared to IA peripheral blood (p<0.05) or HC ST (p<0.05). Upon examination of IA synovial fluid, we report similar findings to ST, whereby CD1c+DC are enriched in synovial fluid compared to PB (p<0.001). Moreover, RNA sequencing and PCA analysis of synovial versus blood CD1c+DC revealed distinct transcriptional variation between both sites. Functionally, synovial CD1c+DC express higher levels of the maturation markers CD80, CD83, CD40, PD-L1 and BTLA (all p<0.05) and have distinct coexpression of these maturation markers which is unique to the synovium. Synovial CD1c+DC are less phagocytic compared to peripheral blood DC, have decreased production of MMP1 and MMP9 and importantly are still capable of additional activation in-vitro. Finally, synovial CD1c+DC induce the proinflammatory cytokines TNFα, GMCSF, IL-17a and IFNγ from CD4+ T-cells in allogeneic DC: T cells cocultures.Conclusion:Mature circulatory CD1c+DC migrate and accumulate in the IA synovium. Synovial DC are present in the IA synovium in a mature state, have distinct tissue specific characteristics and can induce proinflammatory CD4+T cell responses.Acknowledgements:We would like to thank all the patients who contributed to this studyDisclosure of Interests:Mary Canavan: None declared, Viviana Marzaioli: None declared, Vipul Bhargava Employee of: Janssen Research and Development, Sunil Nagpal Employee of: Janssen Research and Development, Phil Gallagher: None declared, Conor Hurson: None declared, Ronan Mullan: None declared, Douglas Veale Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, MSD, UCB, Consultant of: Abbvie, Janssen, Novartis, Pfizer, MSD, UCB, Grant/research support from: Pfizer, Janssen, AbbVie, UCB, Ursula Fearon Speakers bureau: Abbvie, Grant/research support from: Pfizer, Janssen, Abbvie, UCB

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