Assessment of combined vaccination and immune modulation as an anti-tumour therapy

2021 ◽  
Author(s):  
◽  
Emma Victoria Petley
Keyword(s):  
T Cell ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Checkpoint Blockade ◽  
Inkt Cell ◽  
Current Therapy ◽  
Checkpoint Inhibition ◽  
Cell Responses

<p>Glioblastoma multiforme (GBM) is a common and lethal type of brain cancer, with a very poor prognosis. Current therapy consisting of surgical resection, radiation and chemotherapy produces a median survival of only 12-15 months. Therefore, there is a need to develop new therapeutic approaches for the treatment of GBM.  This thesis investigates a new series of synthetic cancer vaccines, conjugating tumour-associated antigens (TAAs) to an isomer of ɑ-Galactosylceramide (ɑ-GalCer), a potent invariant natural killer T (iNKT) cell agonist with documented adjuvant activity. Upon antigen encounter, activated iNKT cells are capable of licensing dendritic cells (DCs) through CD40:CD40L interactions and cytokine production. The licensed DCs subsequently stimulate potent CD8⁺ T cell responses, capable of killing cancerous tissue. Conjugation of ɑ-GalCer to the TAA-derived peptide was achieved via an enzymatically cleavable linker sensitive to cathepsin B activity. This strategy allows co-delivery of the active components, with the rationale that the same DC will be able to co-present both ɑ-GalCer for iNKT cell activation, and peptide to induce an enhanced CD8⁺ T cell responses.  The conjugate vaccines assessed in this thesis were able to induce iNKT cell activation and produce CD8⁺ T cell cytoxicity. However, this did not correlate with in vivo antitumour activity, as the vaccine that incorporated the TAA survivin, produced minimal cytotoxicity but potent anti-tumour responses against an implantable model of glioma.  Enhancing T cell-mediated immune responses has been validated by immune checkpoint inhibition for the treatment of cancer. However, many patients do not respond to the therapy. It is thought that this subset of patients may lack pre-existing T cell responses, which are required for the efficacy of checkpoint inhibition. Therefore, there is considerable interest in whether the use of vaccines that stimulate T cell activation can improve responses to checkpoint blockade and other immune modulating drugs. The survivin vaccine was combined with the immune checkpoint blockade inhibitors ɑ-PD-1, ɑ-CTLA-4 and ɑ-LAG-3, the co-stimulatory agent a-4-1BB, or administered with T regulatory cell (TREG) depletion, to reveal the immunogenicity of the vaccine.  This research revealed that combining the survivin vaccine with the immune checkpoint inhibitor ɑ-CTLA-4 improved overall survival of mice, compared to the vaccine alone. This finding suggests that this combined therapy may be a useful immunotherapeutic strategy for the treatment of GBM.</p>

Assessment of combined vaccination and immune modulation as an anti-tumour therapy

2021 ◽  
Author(s):  
◽  
Emma Victoria Petley
Keyword(s):  
T Cell ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Checkpoint Blockade ◽  
Inkt Cell ◽  
Current Therapy ◽  
Checkpoint Inhibition ◽  
Cell Responses

<p>Glioblastoma multiforme (GBM) is a common and lethal type of brain cancer, with a very poor prognosis. Current therapy consisting of surgical resection, radiation and chemotherapy produces a median survival of only 12-15 months. Therefore, there is a need to develop new therapeutic approaches for the treatment of GBM.  This thesis investigates a new series of synthetic cancer vaccines, conjugating tumour-associated antigens (TAAs) to an isomer of ɑ-Galactosylceramide (ɑ-GalCer), a potent invariant natural killer T (iNKT) cell agonist with documented adjuvant activity. Upon antigen encounter, activated iNKT cells are capable of licensing dendritic cells (DCs) through CD40:CD40L interactions and cytokine production. The licensed DCs subsequently stimulate potent CD8⁺ T cell responses, capable of killing cancerous tissue. Conjugation of ɑ-GalCer to the TAA-derived peptide was achieved via an enzymatically cleavable linker sensitive to cathepsin B activity. This strategy allows co-delivery of the active components, with the rationale that the same DC will be able to co-present both ɑ-GalCer for iNKT cell activation, and peptide to induce an enhanced CD8⁺ T cell responses.  The conjugate vaccines assessed in this thesis were able to induce iNKT cell activation and produce CD8⁺ T cell cytoxicity. However, this did not correlate with in vivo antitumour activity, as the vaccine that incorporated the TAA survivin, produced minimal cytotoxicity but potent anti-tumour responses against an implantable model of glioma.  Enhancing T cell-mediated immune responses has been validated by immune checkpoint inhibition for the treatment of cancer. However, many patients do not respond to the therapy. It is thought that this subset of patients may lack pre-existing T cell responses, which are required for the efficacy of checkpoint inhibition. Therefore, there is considerable interest in whether the use of vaccines that stimulate T cell activation can improve responses to checkpoint blockade and other immune modulating drugs. The survivin vaccine was combined with the immune checkpoint blockade inhibitors ɑ-PD-1, ɑ-CTLA-4 and ɑ-LAG-3, the co-stimulatory agent a-4-1BB, or administered with T regulatory cell (TREG) depletion, to reveal the immunogenicity of the vaccine.  This research revealed that combining the survivin vaccine with the immune checkpoint inhibitor ɑ-CTLA-4 improved overall survival of mice, compared to the vaccine alone. This finding suggests that this combined therapy may be a useful immunotherapeutic strategy for the treatment of GBM.</p>

scholarly journals Monkeypox virus evades antiviral CD4+ and CD8+ T cell responses by suppressing cognate T cell activation

2008 ◽  
Vol 105 (38) ◽  
pp. 14567-14572 ◽  
Author(s):  
E. Hammarlund ◽  
A. Dasgupta ◽  
C. Pinilla ◽  
P. Norori ◽  
K. Fruh ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Monkeypox Virus ◽  
Cell Responses

scholarly journals Mechanisms of induction of CD8⁺ T cell responses by dendritic cells

2021 ◽  
Author(s):  
◽  
Taryn Louise Osmond
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cross Presentation ◽  
Cell Responses ◽  
Circulating Antigen

<p>Splenic CD8α⁺ dendritic cells (DCs) have been described as key antigen presenting cells for the induction of CD8⁺ T cell responses to circulating antigen. This is through a heightened capacity to acquire and present the antigens via the process of cross-presentation, expression of high levels of the co-stimulatory and adhesion molecules required to stimulate CD8⁺ T cells, and the capacity to release high levels of the cytokines required to drive differentiation of CD8⁺ T cells into cytotoxic T lymphocytes (CTLs). However, recent research has indicated that the splenic CD8α⁺ DC population is more heterogeneous than originally thought. A previous study from my own laboratory suggested that a population of CD8α⁺ DCs that express the c-type lectin langerin primarily possess the heightened functions previously attributed to the total CD8α⁺ population. Therefore, the aim of this thesis research was to explore this subset of DCs in more detail, with specific emphasis on gaining mechanistic insight into their ability to elicit CD8⁺ T cell responses to circulating proteins. In the first section of this thesis, the hypothesis that the splenic langerin⁺ CD8α⁺ DCs were the critical subset involved in the induction of strong systemic CD8⁺ T cell responses to circulating antigen was tested in detail. This was examined using a genetically modified mouse model in which langerin-expressing cells could be easily identified and/or specifically depleted. It was first shown that the induction of CD8⁺ T cell responses to the model antigen ovalbumin was dependent on entry into the spleen in the presence of appropriate stimulation, which in these studies was provided by agonists for the toll-like receptors (TLRs) and/or signals from innate-like lymphocytes called natural killer T (NKT) cells. The primary targets for these signals were shown to be splenic langerin⁺ CD8α⁺ DCs, as CD8⁺ T cell responses were significantly reduced in hosts depleted of these cells within the spleen. Furthermore, agonists for TLRs that were not expressed by langerin⁺ CD8α⁺ DCs failed to enhance T cell responses. The langerin⁺ CD8α⁺ DCs were shown to be located in the marginal zone of the spleen, where they could readily screen the blood for antigens, and their function was critical to the induction of CD8⁺ T cell responses within six hours of antigen delivery. Interestingly, other local langerin-negative antigen presenting cells (APCs) were shown to be capable of cross-presentation, but with significantly reduced capacity to prime CD8⁺ T cell responses. Therefore, in the second section of this thesis the hypothesis that the langerin-negative APCs were capable of contributing to CD8⁺ T cell responses with appropriately timed stimuli was investigated. One of the downstream effects of inducing NKT cell activation at the time of priming was shown to be the “pre-conditioning” of langerin-negative DCs, allowing them to respond strongly to subsequent TLR ligation. Using SiglecH-DTR mice, it was shown that plasmacytoid DCs (which are langerin-negative) were pre-conditioned by NKT cell activation, allowing them to respond more actively to the delayed TLR stimulation by producing significantly enhanced levels of IFN-α. This factor was also potentially responsible for “feeding back” to the CD8α⁺ DCs (including langerin-expressing CD8α⁺ DCs), to enhance their function, as indicated by increases in cytokine production. Significantly, the major langerin-negative DC populations, defined as CD8α⁻ DCs, were pre-conditioned to have an enhanced cytokine release response to subsequent stimulation through TLR7, a receptor not expressed by langerin-positive DCs. This enhanced ability to respond to TLR7 ligation permitted these langerin-negative APCs to contribute to increased CD8⁺ T cell accumulation, with enhanced functional activity. Importantly, the CD8⁺ T cell response induced remained significantly dependent on initial cross-priming by langerin⁺ CD8α⁺ DCs, and it was only through pre-conditioning that langerinnegative APCs could contribute to enhancing the T cell response. In the third section of this thesis, the hypothesis that the CD8⁺ T cell responses generated in the presence of langerin⁺ CD8α⁺ DCs were phenotypically and functionally distinct from those responses generated in their absence was tested. No obvious differences were seen in CD8⁺ T cell homing, memory phenotype, restimulatory capacity, and expression of key molecules involved in metabolic function, survival and cytolytic function. However, in vivo cytotoxic function several weeks after priming was comparable, suggesting that this function was not related to initial burst size, providing some evidence of difference in function between CD8⁺ T cells primed in the presence or absence of langerin⁺ CD8α⁺ DCs. In summary, the splenic langerin⁺ CD8α⁺ DCs are the major subset responsible for cross-priming CD8⁺ T cell responses to circulating antigen, and for interpreting multiple stimulatory signals for enhancing the response. However, effective CD8⁺ T cell responses can be generated in their absence, particularly when antigens are provided in the context of appropriately temporally phased stimuli.</p>

scholarly journals Analysis of Iron and Iron-Interacting Protein Dynamics During T-Cell Activation

2021 ◽  
Vol 12 ◽  
Author(s):  
Megan R. Teh ◽  
Joe N. Frost ◽  
Andrew E. Armitage ◽  
Hal Drakesmith
Keyword(s):  
T Cell ◽  
Iron Deficiency ◽  
T Cell Activation ◽  
Serum Iron ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
High Serum ◽  
Knock Out ◽  
Cell Responses

Recent findings have shown that iron is a powerful regulator of immune responses, which is of broad importance because iron deficiency is highly prevalent worldwide. However, the underlying reasons of why iron is needed by lymphocytes remain unclear. Using a combination of mathematical modelling, bioinformatic analysis and experimental work, we studied how iron influences T-cells. We identified iron-interacting proteins in CD4+ and CD8+ T-cell proteomes that were differentially expressed during activation, suggesting that pathways enriched with such proteins, including histone demethylation, may be impaired by iron deficiency. Consistent with this, iron-starved Th17 cells showed elevated expression of the repressive histone mark H3K27me3 and displayed reduced RORγt and IL-17a, highlighting a previously unappreciated role for iron in T-cell differentiation. Quantitatively, we estimated T-cell iron content and calculated that T-cell iron demand rapidly and substantially increases after activation. We modelled that these increased requirements will not be met during clinically defined iron deficiency, indicating that normalizing serum iron may benefit adaptive immunity. Conversely, modelling predicted that excess serum iron would not enhance CD8+ T-cell responses, which we confirmed by immunising inducible hepcidin knock-out mice that have very high serum iron concentrations. Therefore, iron deficiency impairs multiple aspects of T-cell responses, while iron overload likely has milder effects.

scholarly journals Targeting of antigens to B cells augments antigen-specific T-cell responses and breaks immune tolerance to tumor-associated antigen MUC1

Blood ◽  
2008 ◽  
Vol 112 (7) ◽  
pp. 2817-2825 ◽  
Author(s):  
Chuanlin Ding ◽  
Li Wang ◽  
Jose Marroquin ◽  
Jun Yan
Keyword(s):  
T Cell ◽  
B Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Vaccine Development ◽  
High Titer ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses

Abstract B cells are antibody (Ab)–secreting cells as well as potent antigen (Ag)–presenting cells that prime T-cell activation, which evokes great interest in their use for vaccine development. Here, we targeted ovalbumin (OVA) to B cells via CD19 and found that a single low dose of anti–CD19-OVA conjugates, but not isotype mAb-OVA, stimulated augmented CD4 and CD8 T-cell proliferation and expansion. Administration of TLR9 agonist CpG could significantly enhance long-term T-cell survival. Similar results were obtained when the tumor-associated Ag MUC1 was delivered to B cells. MUC1 transgenic (Tg) mice were previously found to lack effective T-cell help and produce low-titer of anti-MUC1 Abs after vaccination. Targeting MUC1 to B cells elicited high titer of anti-MUC1 Abs with different isotypes, predominantly IgG2a and IgG2b, in MUC1 Tg mice. The isotype switching of anti-MUC1 Ab was CD4 dependent. In addition, IFN-γ–producing CD8 T cells and in vivo cytolytic activity were significantly increased in these mice. The mice also showed significant resistance to MUC1+ lymphoma cell challenge both in the prophylactic and therapeutic settings. We conclude that Ags targeting to B cells stimulate CD4 and CD8 T-cell responses as well as Th-dependent humoral immune responses.

scholarly journals IMMU-09. COMBINATION IMMUNE TREATMENT OF A HIGHLY AGGRESSIVE ORTHOTOPIC MURINE GLIOBLASTOMA WITH CHECKPOINT BLOCKADE AND MULTI-VALENT NEOANTIGEN VACCINATION

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi120-vi121
Author(s):  
Connor Liu ◽  
Maximilian Schaettler ◽  
Jay Bowman-Kirigin ◽  
Dale Kobayashi ◽  
Chris Miller ◽  
...  
Keyword(s):  
T Cell ◽  
Specific Antigen ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Checkpoint Blockade ◽  
Immune Recognition ◽  
Cell Responses ◽  
Recent Success ◽  
Whole Exome ◽  
Survival Studies

Abstract Recent success using immunotherapies to treat a growing range of cancer types has reinvigorated efforts to identify effective immune-based treatments for glioblastoma (GBM). However, the limited clinical benefit observed in GBM patients treated with checkpoint blockade immunotherapy (CBI) has indicated a need for more rigorous approaches to augment host-immune recognition and killing of GBM. Of the myriad barriers to effective brain tumor immunotherapy, one potentially critical consideration is that a more systematic approach to tumor-specific antigen identification and targeting is necessary to potently stimulate and direct T cells to treat GBM. Therefore, in this study we set out to identify endogenous tumor neoantigens in the anti-PD-L1 resistant murine glioblastoma, CT2A, and assess the efficacy of neoantigen vaccination in combination with anti-PD-L1 treatment. In order to identify candidate CT2A neoantigens, we employed DNA whole exome sequencing, RNA sequencing, and in silico neoantigen prediction analyses. High-affinity H-2Kb and H-2Db candidate CT2A neoantigens were screened for immunogenicity by IFN-γ ELISPOT assays. Of the 30 top-ranking neoantigen candidates, 13 demonstrated immunogenic CD8+ T cell responses in the spleens of mice vaccinated with mutant peptides. Assessing for endogenous reactivity, we identified neoantigen specific CD8+ T cell responses in the intracranial TIL and draining lymph nodes to two H2-Kb restricted, Epb4H471L and Pomgnt1R497L, and one H2-Db restricted neoantigen, Plin2G332R. Survival studies showed that therapeutic neoantigen vaccination with Epb4H471L, Pomgnt1R497L, and Plin2G332R, in combination with anti-PD-L1 checkpoint blockade was superior to either neoantigen vaccination or anti-PD-L1 therapy alone. Thus, by applying a cancer immunogenomics approach to identify endogenous neoantigen reactivity in an aggressive and treatment resistant murine glioblastoma, we provide a preclinical framework to investigate the effects of multi-modality immunotherapeutic interventions in anti-glioma immunity.

scholarly journals Liposomal Nanovaccine Containing α-Galactosylceramide and Ganglioside GM3 Stimulates Robust CD8+ T Cell Responses via CD169+ Macrophages and cDC1

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 56
Author(s):  
Joanna Grabowska ◽  
Dorian A. Stolk ◽  
Maarten K. Nijen Twilhaar ◽  
Martino Ambrosini ◽  
Gert Storm ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Type I ◽  
Ganglioside Gm3 ◽  
Cell Responses ◽  
Anti Cancer

Successful anti-cancer vaccines aim to prime and reinvigorate cytotoxic T cells and should therefore comprise a potent antigen and adjuvant. Antigen targeting to splenic CD169+ macrophages was shown to induce robust CD8+ T cell responses via antigen transfer to cDC1. Interestingly, CD169+ macrophages can also activate type I natural killer T-cells (NKT). NKT activation via ligands such as α-galactosylceramide (αGC) serve as natural adjuvants through dendritic cell activation. Here, we incorporated ganglioside GM3 and αGC in ovalbumin (OVA) protein-containing liposomes to achieve both CD169+ targeting and superior DC activation. The systemic delivery of GM3-αGC-OVA liposomes resulted in specific uptake by splenic CD169+ macrophages, stimulated strong IFNγ production by NKT and NK cells and coincided with the maturation of cDC1 and significant IL-12 production. Strikingly, superior induction of OVA-specific CD8+ T cells was detected after immunization with GM3-αGC-OVA liposomes. CD8+ T cell activation, but not B cell activation, was dependent on CD169+ macrophages and cDC1, while activation of NKT and NK cells were partially mediated by cDC1. In summary, GM3-αGC antigen-containing liposomes are a potent vaccination platform that promotes the interaction between different immune cell populations, resulting in strong adaptive immunity and therefore emerge as a promising anti-cancer vaccination strategy.

scholarly journals A262 DIFFERENTIAL PHENOTYPES AND LOCALIZATION OF CD8+ T CELL RESPONSES TO ACUTE AND CHRONIC ENTERIC VIRAL INFECTION

2020 ◽  
Vol 3 (Supplement_1) ◽  
pp. 139-140
Author(s):  
B K Hardman ◽  
L C Osborne
Keyword(s):  
T Cells ◽  
T Cell ◽  
Viral Infection ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Post Infection ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses

Abstract Background Human Norovirus infection is the most common viral cause of gastroenteritis globally and the second most reported viral infection in Canada after the common cold. Most infections are acute, symptomatic, and rapidly cleared but some cases persist asymptomatically or induce post-infectious irritable bowel syndrome. Despite the global burden of these infections, no vaccine to prevent disease exists nor is the mechanism for persistence understood. MNV-CW3 and MNV-CR6 are murine noroviruses which demonstrate distinct biological behaviors that correlate with differential quantity and quality of antiviral CD8+ T cell responses. MNV-CW3 causes acute systemic infections initiated in the small intestine and cleared by day 8 due to a robust antiviral CD8+ T cell response. In contrast, MNV-CR6 causes chronic infections localized to the colonic intestinal epithelium and induces fewer antiviral CD8+ T cells with reduced effector molecule expression. Aims This research interrogates the mechanisms underlying strain-specific differential antiviral CD8+ T cell responses. Methods At days 3, 4, 5 and 8 post-infection, the phenotype and quantity of adoptively transferred MNV specific CD8+ T cells in the spleen, mesenteric lymph node (MLN), and the small and large intestine are analyzed by flow cytometry. Concurrently, immunofluorescent microscopy is used to determine whether CD8+ T cells are broadly disseminated throughout the intestines or localize in acute clusters of antiviral response. Combining these complementary techniques provides novel insight into mechanisms governing intestinal antiviral T cell responses. Results Activated MNV-specific CD8 T cells first accumulate in the MLN following oral infection with both MNV-CW3 and CR6, suggesting this is the site of immune activation. Supporting this hypothesis, preliminary data indicates that preventing T cell egress from activation sites by treatment with the S1PR1 agonist FTY720 leads to an enrichment of activated CD8+ T cells in the MLN following CW3 infection. Notably, the earliest stages of CD8+ T cell activation to CR6 infection is delayed compared to that elicited by CW3. Furthermore, at the peak of CD8+ T cell expansion (day 8 post-infection), CR6-elicited CD8+ T cells preferentially develop into short-lived effector populations rather than memory precursor populations. Conclusions These data reveal previously unknown differences in early events in CD8+ T cell activation following infection with two highly related viral strains that correlate with long-lasting effects on T cell differentiation and function. We are currently investigating the hypothesis that MNV-CW3 and CR6 may induce activation of distinct populations of, or pathways in, APC populations that would drive these differences. These results may have broad impacts on our understanding of how non-latent, chronic viral infections persist within a host. Funding Agencies CIHR

scholarly journals Neoantigen Dendritic Cell Vaccination Combined with Anti-CD38 and CpG Elicits Anti-Tumor Immunity against the Immune Checkpoint Therapy-Resistant Murine Lung Cancer Cell Line LLC1

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5508
Author(s):  
Changbo Sun ◽  
Koji Nagaoka ◽  
Yukari Kobayashi ◽  
Hidewaki Nakagawa ◽  
Kazuhiro Kakimi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Regulatory T Cells ◽  
Cell Line ◽  
Immune Checkpoint ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Pulsed Dc

An important factor associated with primary resistance to immune-checkpoint therapies (ICT) is a “cold” tumor microenvironment (TME), characterized by the absence of T cell infiltration and a non-inflammatory milieu. Whole-exome and RNA sequencing to predict neoantigen expression was performed on the LLC1 cell line which forms “cold” tumors in mice. Dendritic cell (DC)-based vaccination strategies were developed using candidate neoantigen long peptides (LPs). A total of 2536 missense mutations were identified in LLC1 and of 132 candidate neoantigen short peptides, 25 were found to induce CD8+ T cell responses. However, they failed to inhibit LLC1 growth when incorporated into a cancer vaccine. In contrast, DCs pulsed with LPs induced CD4+ and CD8+ T cell responses and one of them, designated L82, delayed LLC1 growth in vivo. By RNA-Seq, CD38 was highly expressed by LLC1 tumor cells and, therefore, anti-CD38 antibody treatment was combined with L82-pulsed DC vaccination. This combination effectively suppressed tumor growth via a mechanism relying on decreased regulatory T cells in the tumor. This study demonstrated that an appropriate vaccination strategy combining neoantigen peptide-pulsed DC with anti-CD38 antibody can render an ICT-resistant “cold” tumor susceptible to immune rejection via a mechanism involving neutralization of regulatory T cells.

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