scholarly journals Modulation of Dendritic Cells by Microbiota Extracellular Vesicles Influences the Cytokine Profile and Exosome Cargo

Nutrients ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 344
Author(s):  
Natalia Diaz-Garrido ◽  
Josefa Badia ◽  
Laura Baldomà
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Immune Responses ◽  
Extracellular Vesicles ◽  
T Cell Activation ◽  
T Cell Responses ◽  
E Coli ◽  
Cell Responses ◽  
Secreted Factors

Gut bacteria release extracellular vesicles (BEVs) as an intercellular communication mechanism that primes the host innate immune system. BEVs from E. coli activate dendritic cells (DCs) and subsequent T-cell responses in a strain-specific manner. The specific immunomodulatory effects were, in part, mediated by differential regulation of miRNAs. This study aimed to deepen understanding of the mechanisms of BEVs to drive specific immune responses by analyzing their impact on DC-secreted cytokines and exosomes. DCs were challenged with BEVs from probiotic and commensal E. coli strains. The ability of DC-secreted factors to activate T-cell responses was assessed by cytokine quantification in indirect DCs/naïve CD4+ T-cells co-cultures on Transwell supports. DC-exosomes were characterized in terms of costimulatory molecules and miRNAs cargo. In the absence of direct cellular contacts, DC-secreted factors triggered secretion of effector cytokines by T-cells with the same trend as direct DC/T-cell co-cultures. The main differences between the strains influenced the production of Th1- and Treg-specific cytokines. Exosomes released by BEV-activated DCs were enriched in surface proteins involved in antigen presentation and T-cell activation, but differed in the content of immune-related miRNA, depending on the origin of the BEVs. These differences were consistent with the derived immune responses.

scholarly journals Vector Order Determines Protection against Pathogenic Simian Immunodeficiency Virus Infection in a Triple-Component Vaccine by Balancing CD4+ and CD8+ T-Cell Responses

2017 ◽  
Vol 91 (23) ◽  
Author(s):  
Ulrike Sauermann ◽  
Antonia Radaelli ◽  
Nicole Stolte-Leeb ◽  
Katharina Raue ◽  
Massimiliano Bissa ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Responses ◽  
Target Cells ◽  
Aids Vaccine ◽  
Cell Responses ◽  
Antibody Titers

ABSTRACT An effective AIDS vaccine should elicit strong humoral and cellular immune responses while maintaining low levels of CD4+ T-cell activation to avoid the generation of target cells for viral infection. The present study investigated two prime-boost regimens, both starting vaccination with single-cycle immunodeficiency virus, followed by two mucosal boosts with either recombinant adenovirus (rAd) or fowlpox virus (rFWPV) expressing SIVmac239 or SIVmac251 gag/pol and env genes, respectively. Finally, vectors were switched and systemically administered to the reciprocal group of animals. Only mucosal rFWPV immunizations followed by systemic rAd boost significantly protected animals against a repeated low-dose intrarectal challenge with pathogenic SIVmac251, resulting in a vaccine efficacy (i.e., risk reduction per exposure) of 68%. Delayed viral acquisition was associated with higher levels of activated CD8+ T cells and Gag-specific gamma interferon (IFN-γ)-secreting CD8+ cells, low virus-specific CD4+ T-cell responses, and low Env antibody titers. In contrast, the systemic rFWPV boost induced strong virus-specific CD4+ T-cell activity. rAd and rFWPV also induced differential patterns of the innate immune responses, thereby possibly shaping the specific immunity. Plasma CXCL10 levels after final immunization correlated directly with virus-specific CD4+ T-cell responses and inversely with the number of exposures to infection. Also, the percentage of activated CD69+ CD8+ T cells correlated with the number of exposures to infection. Differential stimulation of the immune response likely provided the basis for the diverging levels of protection afforded by the vaccine regimen. IMPORTANCE A failed phase II AIDS vaccine trial led to the hypothesis that CD4+ T-cell activation can abrogate any potentially protective effects delivered by vaccination or promote acquisition of the virus because CD4+ T helper cells, required for an effective immune response, also represent the target cells for viral infection. We compared two vaccination protocols that elicited similar levels of Gag-specific immune responses in rhesus macaques. Only the animal group that had a low level of virus-specific CD4+ T cells in combination with high levels of activated CD8+ T cells was significantly protected from infection. Notably, protection was achieved despite the lack of appreciable Env antibody titers. Moreover, we show that both the vector and the route of immunization affected the level of CD4+ T-cell responses. Thus, mucosal immunization with FWPV-based vaccines should be considered a potent prime in prime-boost vaccination protocols.

T Cell Responses in Patients Vaccinated with Telomerase (hTERT)-mRNA Transfected Dendritic Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 373-373
Author(s):  
Else Marit Inderberg Suso ◽  
Anne-Marie Rasmussen ◽  
Steinar Aamdal ◽  
Svein Dueland ◽  
Gustav Gaudernack ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Immune Responses ◽  
Cancer Patients ◽  
Cd8 T Cells ◽  
Stable Disease ◽  
T Cell Responses ◽  
Htert Mrna ◽  
Cell Responses

Abstract Abstract 373 Two cancer patients were vaccinated with dendritic cells (DC) loaded with telomerase (hTERT) mRNA to investigate the safety, tolerability and immunological response to vaccination prior to the start of a new phase I/II clinical trial. Following written informed consent one primary lung adenocarcinoma with metastasis and one patient with a relapsed pancreatic ductal type of adenocarcinoma, were treated with autologus monocyte-derived DC transfected with mRNA encoding hTERT. The patients first received four weekly injections administered intradermally followed by monthly booster injections. Peripheral blood mononuclear cells (PBMC) at each vaccination time point were tested in vitro with transfected DC and a panel of 24 overlapping hTERT peptides. In addition, hTERT-specific CD8+ T cells were monitored by pentamer staining. The treatment was well tolerated with minor side effects. Immune responses against telomerase-transfected DC and some of the overlapping hTERT peptides were detected in both patients. We also detected hTERT-specific CD8+ T cells in both patients by pentamer staining in post-vaccination samples. The lung cancer patients obtained a stable disease that lasted 18 months while the patient with pancreas cancer who started the DC vaccination in July 2007 following palliative chemotherapy, still is in stable disease by continuously boost vaccination. T-cell responses against telomerase epitopes have also been identified in both non-vaccinated cancer patients and cancer patients previously vaccinated with telomerase peptide. Since patients with these findings often show extraordinary clinical courses of their disease we hypothesize that it exists a high degree of immunogenicity and HLA promiscuity for some telomerase epitopes. In this study we have shown that vaccination with hTERT-mRNA transfected DC is safe and able to induce robust immune responses to several telomerase T-cell epitopes both in CD4+ and CD8+ T cells. This opens up the possibility for a broad clinical application of mRNA hTERT DC vaccines. Furthermore, responding T cells identified in these patients are strong candidates for T-cell receptor cloning and the receptors identified can thereafter be transferred into T cells creating the next generation of immuno-gene therapy with retargeted T cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Interleukin-12p70 Expression by Dendritic Cells of HIV-1-Infected Patients Fails to Stimulategag-Specific Immune Responses

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Ellen Van Gulck ◽  
Nathalie Cools ◽  
Derek Atkinson ◽  
Lotte Bracke ◽  
Katleen Vereecken ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
Hiv Replication ◽  
Cell Responses ◽  
Antigen Presenting ◽  
Hiv 1 ◽  
Unique Capability

A variety of immune-based therapies has been developed in order to boost or induce protective CD8+T cell responses in order to control HIV replication. Since dendritic cells (DCs) are professional antigen-presenting cells (APCs) with the unique capability to stimulate naïve T cells into effector T cells, their use for the induction of HIV-specific immune responses has been studied intensively. In the present study we investigated whether modulation of the activation state of DCs electroporated with consensus codon-optimized HxB2gagmRNA enhances their capacity to induce HIVgag-specific T cell responses. To this end, mature DCs were (i) co-electroporated with mRNA encoding interleukin (IL)-12p70 mRNA, or (ii) activated with a cytokine cocktail consisting of R848 and interferon (IFN)-γ. Our results confirm the ability of HxB2gag-expressing DCs to expand functional HIV-specific CD8+T cells. However, although most of the patients had detectablegag-specific CD8+T cell responses, no significant differences in the level of expansion of functional CD8+T cells could be demonstrated when comparing conventional or immune-modulated DCs expressing IL-12p70. This result which goes against expectation may lead to a re-evaluation of the need for IL-12 expression by DCs in order to improve T-cell responses in HIV-1-infected individuals.

scholarly journals Immunization with host-type CD8α+ dendritic cells reduces experimental acute GVHD in an IL-10–dependent manner

Blood ◽  
2010 ◽  
Vol 115 (3) ◽  
pp. 724-735 ◽  
Author(s):  
Tomomi Toubai ◽  
Chelsea Malter ◽  
Isao Tawara ◽  
Chen Liu ◽  
Evelyn Nieves ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
Class Ii ◽  
Cell Responses ◽  
Histocompatibility Complex

Abstract Little is known about the role of active immunization in suppressing undesirable immune responses. Because CD8α+ dendritic cells (DCs) suppress certain immune responses, we tested the hypothesis that immunization of donors with host-derived CD8α+ DCs will reduce host-specific donor T-cell responses. BALB/c T cells from the animals that were immunized with B6 CD8α+ DCs demonstrated, in vitro and in vivo, significantly reduced proliferation and secretion of inflammatory cytokines but showed enhanced secretion of interleukin-10 (IL-10). The responses against third-party and model antigens were preserved demonstrating antigen specificity. The in vivo relevance was further demonstrated by the reduction on graft-versus-host disease (GVHD) in both a major histocompatibility complex–mismatched clinically relevant BALB/c → B6 model and major histocompatibility complex–matched, minor-mismatched C3H.SW → B6 model of GVHD. Immunization of the donors that were deficient in IL-10 (IL-10−/−) or with CD8α+ DCs from B6 class II (class II−/−) failed to reduce T-cell responses, demonstrating (1) a critical role for secretion of IL-10 by donor T cells and (2) a direct contact between the T cells and the CD8α+ DCs. Together, these data may represent a novel strategy for reducing GVHD and suggest a broad counterintuitive role for vaccination strategies in mitigating undesirable immune responses in an antigen-specific manner.

scholarly journals Modulation of Naive CD4+ T-Cell Responses to an Airway Antigen during Pulmonary Mycobacterial Infection

2007 ◽  
Vol 75 (5) ◽  
pp. 2260-2268 ◽  
Author(s):  
Mursalin M. Anis ◽  
Scott A. Fulton ◽  
Scott M. Reba ◽  
Clifford V. Harding ◽  
W. Henry Boom
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Responses ◽  
Mycobacterial Infection ◽  
Antigen Challenge ◽  
Cell Responses

ABSTRACT During pulmonary mycobacterial infection, there is increased trafficking of dendritic cells from the lungs to the draining lymph nodes. We hypothesized that ongoing mycobacterial infection would modulate recruitment and activation of antigen-specific naive CD4+ T cells after airway antigen challenge. BALB/c mice were infected by aerosol with Mycobacterium bovis BCG. At peak bacterial burden in the lungs (4 to 6 weeks postinfection), carboxy-fluorescein diacetate succinimidyl ester-labeled naive ovalbumin-specific DO11.10 T cells were adoptively transferred into infected and uninfected mice. Recipient mice were challenged intranasally with soluble ovalbumin (OVA), and OVA-specific T-cell responses were measured in the lungs, draining mediastinal lymph nodes (MLN), and spleens. OVA challenge resulted in increased activation and proliferation of OVA-specific T cells in the draining MLN of both infected and uninfected mice. However, only BCG-infected mice had prominent OVA-specific T-cell activation, proliferation, and Th1 differentiation in the lungs. BCG infection caused greater distribution of airway OVA to pulmonary dendritic cells and enhanced presentation of OVA peptide by lung CD11c+ cells. Together, these data suggest that an existing pulmonary mycobacterial infection alters the phenotype of lung dendritic cells so that they can activate antigen-specific naive CD4+ T cells in the lungs in response to airway antigen challenge.

Activation of influenza virus–specific CD4+ and CD8+ T cells: a new role for plasmacytoid dendritic cells in adaptive immunity

Blood ◽  
2003 ◽  
Vol 101 (9) ◽  
pp. 3520-3526 ◽  
Author(s):  
Jean-François Fonteneau ◽  
Michel Gilliet ◽  
Marie Larsson ◽  
Ida Dasilva ◽  
Christian Münz ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Influenza Virus ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
Cell Responses ◽  
Adaptive Immune

Plasmacytoid dendritic cells (pDCs) contribute to innate antiviral immune responses by producing type I interferons (IFNs) upon exposure to enveloped viruses. However, their role in adaptive immune responses, such as the initiation of antiviral T-cell responses, is not known. In this study, we examined interactions between blood pDCs and influenza virus with special attention to the capacity of pDCs to activate influenza-specific T cells. pDCs were compared with CD11c+ DCs, the most potent antigen-presenting cells (APCs), for their capacity to activate T-cell responses. We found that like CD11c+ DCs, pDCs mature following exposure to influenza virus, express CCR7, and produce proinflammatory chemokines, but differ in that they produce type I IFN and are resistant to the cytopathic effect of the infection. After influenza virus exposure, both DC types exhibited an equivalent efficiency to expand anti–influenza virus cytotoxic T lymphocytes (CTLs) and T helper 1 (TH1) CD4+ T cells. Our results pinpoint a new role of pDCs in the induction of antiviral T-cell responses and suggest that these DCs play a prominent role in the adaptive immune response against viruses.

scholarly journals 326 SARS-CoV-2 specific T-cells in TIL from patients with epithelial cancer

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A352-A352
Author(s):  
Pedro Noronha ◽  
Georgia Paraschoudi ◽  
Eric Sousa ◽  
Jéssica Kamiki ◽  
Patrícia António ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
T Cell Responses ◽  
T Cell Epitopes ◽  
Ifn Gamma ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Cellular Immune

BackgroundSARS-CoV-2 primarily infects the upper and lower airway system, yet also endothelial cells and multiple tissues/organ systems. Anti-SARS-CoV-2 directed cellular immune responses may be deleterious or may confer immune protection – more research is needed in order to link epitope-specific T-cell responses with clinically relevant endpoints.1 Analysis of epitope reactivity in blood from healthy individuals showed pre-existing (CD4+) reactivity most likely due to previous exposure to the common old coronavirus species HCoV-OC43, HCoV-229E, - NL63 or HKU1, or – not mutually exclusive - cross-reactive T-cell responses that would recognize SARS-CoV-2, yet also other non-SARS-CoV-2 targets.2,3 Detailed single cell analysis in PBMCs from patients with COVID-19 showed strong T-cell activation and expansion of TCR gamma – delta T-cells in patients with fast recovery or mild clinical symptoms.4 Previous studies examining antigen-specific T-cell responses in tumor-infiltrating T-cells (TIL) showed that EBV or CMV-specific cellular immune responses in TIL from patients with melanoma or pancreatic cancer. Such virus -specific T-cells may represent ‘bystander’ T-cell activation, yet they may also impact on the quality and quantity of anti-tumor directed immune responses. We tested therefore TIL expanded from 5 patients with gastrointestinal cancer, who underwent elective tumor surgery during the COVID-19 pandemic for recognition of a comprehensive panel of SARS-CoV-2 T-cell epitopes and compared the reactivity, defined by IFN-gamma production to TIL reactivity in TIL harvested from patients in 2018, prior to the pandemic.MethodsA set of 187 individual T-cell epitopes were tested for TIL recognition using 100IU IL-2 and 100 IU IL-15. Different peptide epitopes were selected: i) all epitopes were not shared with the 4 common old coronavirus species, ii) some peptides were unique for SARS-CoV-2, and iii) others were shared with SARS-CoV-1. Antigen targets were either 15 mers or 9mers for MHC class II or class I epitopes, respectively, derived from the nucleocapsid, membrane, spike protein, ORF8 or the ORF3a. The amount of IFN-gamma production was reported as pg/10e4 cells/epitope/5 days. Controls included CMV and EBV peptides.ResultsWe detected strong IFN-gamma production directed against antigenic ‘hotspots’ including the ORF3a, epitopes from the SARS-CoV-2 nucleocapsid and spike protein with a range of 12 up to 30 targets being recognized/TIL.ConclusionsSARS-CoV-2 epitope recognition, defined by IFN production, can be readily detected in TIL from patients who underwent surgery during the pandemic, which is not the case for TIL harvested prior to the circulating SARS-CoV-2. This suggests a broader exposure of individuals to SARS-CoV-2 and shows that SARS-CoV-2 responses may shape the quality and quantity of anti-cancer directed cellular immune responses in patients with solid epithelial malignancies.AcknowledgementsWe thank the Surgery, Pathology and Vivarium Units of Champalimaud Clinical Center (N. Figueiredo, A. Brandl, A. Beltran, M. Castillo, C. Silva ).Ethics ApprovalThis study was approved by the Champalimaud Foundation Ethics Committee.ConsentAll donors provided written consent and the study was approved by the local ethics committee. The study is in compliance with the Declaration of Helsinki.ReferencesGrifoni, A., Weiskopf, D., Ramirez, S. I., Mateus, J., Dan, J. M., Moderbacher, C. R., Rawlings, S. A., Sutherland, A., Premkumar, L., Jadi, R. S., Marrama, D., de Silva, A. M., Frazier, A., Carlin, A. F., Greenbaum, J. A., Peters, B., Krammer, F., Smith, D. M., Crotty, S., & Sette, A. ( 2020). Targets of T Cell Responses to SARS-CoV-2 Coronavirus in Humans with COVID-19 Disease and Unexposed Individuals. Cell, 181(7), 1489–1501.e15. https://doi.org/10.1016/j.cell.2020.05.015Mateus, J., Grifoni, A., Tarke, A., Sidney, J., Ramirez, S. I., Dan, J. M., Burger, Z. C., Rawlings, S. A., Smith, D. M., Phillips, E., Mallal, S., Lammers, M., Rubiro, P., Quiambao, L., Sutherland, A., Yu, E. D., da Silva Antunes, R., Greenbaum, J., Frazier, A., … Weiskopf, D. ( 2020). Selective and cross-reactive SARS-CoV-2 T cell epitopes in unexposed humans. Science, eabd3871. https://doi.org/10.1126/science.abd3871Le Bert, N., Tan, A. T., Kunasegaran, K., Tham, C. Y. L., Hafezi, M., Chia, A., Chng, M. H. Y., Lin, M., Tan, N., Linster, M., Chia, W. N., Chen, M. I.-C., Wang, L.-F., Ooi, E. E., Kalimuddin, S., Tambyah, P. A., Low, J. G.-H., Tan, Y.-J., & Bertoletti, A. ( 2020). SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls. Nature, 584(7821), 457–462. https://doi.org/10.1038/s41586-020-2550-zZhang, J., Wang, X., Xing, X. et al. Single-cell landscape of immunological responses in patients with COVID-19. Nat Immunol 2020;21:1107–1118. https://doi.org/10.1038/s41590-020-0762-x

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.

scholarly journals 413 GEN-009, a personalized neoantigen vaccine, elicits robust immune responses in individuals with advanced or metastatic solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A438-A438
Author(s):  
Mara Shainheit ◽  
Devin Champagne ◽  
Gabriella Santone ◽  
Syukri Shukor ◽  
Ece Bicak ◽  
...  
Keyword(s):  
Clinical Trial ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Solid Tumors ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Checkpoint Blockade ◽  
T Cell Subsets ◽  
Cell Responses

BackgroundATLASTM is a cell-based bioassay that utilizes a cancer patient‘s own monocyte-derived dendritic cells and CD4+ and CD8+ T cells to screen their mutanome and identify neoantigens that elicit robust anti-tumor T cell responses, as well as, deleterious InhibigensTM.1 GEN-009, a personalized vaccine comprised of 4–20 ATLAS-identified neoantigens combined with Hiltonol®, harnesses the power of neoantigen-specific T cells to treat individuals with solid tumors. The safety and efficacy of GEN-009 is being assessed in a phase 1/2a clinical trial (NCT03633110).MethodsA cohort of 15 adults with solid tumors were enrolled in the study. During the screening period, patients received standard of care PD-1-based immunotherapies appropriate for their tumor type. Subsequently, patients were immunized with GEN-009 with additional doses administered at 3, 6, 12, and 24 weeks. Peripheral blood mononuclear cells (PBMCs) were collected at baseline, pre-vaccination (D1), as well as 29, 50, 92, and 176 days post first dose. Vaccine-induced immunogenicity and persistence were assessed by quantifying neoantigen-specific T cell responses in ex vivo and in vitro stimulation dual-analyte fluorospot assays. Polyfunctionality of neoantigen-specific T cells was evaluated by intracellular cytokine staining. Additionally, potential correlations between the ATLAS-identified profile and vaccine-induced immunogenicity were assessed.ResultsGEN-009 augmented T cell responses in 100% of evaluated patients, attributable to vaccine and not checkpoint blockade. Furthermore, neoantigen-induced secretion of IFNγ and/or TNFα by PBMCs, CD4+, and CD8+ T cells was observed in all patients. Responses were primarily from polyfunctional TEM cells and detectable in both CD4+ and CD8+ T cell subsets. Some patients had evidence of epitope spreading. Unique response patterns were observed for each patient with no apparent relationship between tumor types and time to emergence, magnitude or persistence of response. Ex vivo vaccine-induced immune responses were observed as early as 1 month, and in some cases, persisted for 176 days. Clinical efficacy possibly attributable to GEN-009 was observed in several patients, but no correlation has yet been identified with neoantigen number or magnitude of immune response.ConclusionsATLAS empirically identifies stimulatory neoantigens using the patient‘s own immune cells. GEN-009, which is comprised of personalized, ATLAS-identified neoantigens, elicits early, long-lasting and polyfunctional neoantigen-specific CD4+ and CD8+ T cell responses in individuals with advanced cancer. Several patients achieved clinical responses that were possibly attributable to vaccine; efforts are underway to explore T cell correlates of protection. These data support that GEN-009, in combination with checkpoint blockade, represents a unique approach to treat solid tumors.AcknowledgementsWe are grateful to the patients and their families who consented to participate in the GEN-009-101 clinical trial.Trial RegistrationNCT03633110Ethics ApprovalThis study was approved by Western Institutional Review Board, approval number 1-1078861-1. All subjects contributing samples provided signed individual informed consent.ReferenceDeVault V, Starobinets H, Adhikari S, Singh S, Rinaldi S, Classon B, Flechtner J, Lam H. Inhibigens, personal neoantigens that drive suppressive T cell responses, abrogate protection of therapeutic anti-tumor vaccines. J. Immunol 2020; 204(1 Supplement):91.15.

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