scholarly journals Increasing the potency of dendritic cell based vaccines for the treatment of cancer

2021 ◽  
Author(s):  
◽  
Dianne Sika-Paotonu

<p>Tumours can be eradicated by T cells that recognise unique tumour-associated antigens. These T cells are initially stimulated by dendritic cells (DCs) that have acquired antigens from tumour tissue. Vaccination strategies that increase the frequencies of tumour-specific T cells by enhancing the activity of DCs are being evaluated in the clinic as novel cancer therapies. Our hypothesis is that existing DC-based vaccination strategies can be improved by stimulating toll-like receptor (TLR) signalling in the DCs, and also by encouraging interactions with iNKT cells, as these two activities are known to enhance DC function. It was also hypothesised that superior T cell responses could be induced by combining these two activities together. We used the TLR 4 agonist monophosphoryl lipid A (MPL) alone and in combination with other TLR agonists to achieve effective activation of bone marrow-derived DCs (BM-DCs) cultured in-vitro, which was characterised by upregulated expression of maturation markers on the cell surface, and enhanced release of pro-inflammatory cytokines. Some TLR agonist combinations provided significantly enhanced activities in this regard, notably the combination of MPL with either the TLR 2 agonist Pam3Cys, or the TLR 7/8 agonist Resiquimod. Although in-vitro activated BM-DCs were unable to induce stronger antigen-specific CD8+ T cell responses after intravenous injection when compared to BMDCs without TLR stimulation, enhanced CD8+ T cell responses were achieved in-vivo with the co-administration of TLR ligands, implying that TLR stimulation needed to act on cells of the host. Further studies identified the langerin-expressing CD8ɑ+ splenic DC subset in the spleen as recipients of antigen that was transferred from injected cells, and that these recipients were participants in the cross-presentation and T cell priming activities driving the CD8+ T cell response after vaccination. Antigen-loaded BM-DCs carrying the NKT cell ligand ɑ-galactosylceramide (ɑ-GalCer) were found to consistently increase antigen-specific CD8+ T cell responses in-vivo, and also cytotoxic responses as seen in cytotoxic killing assays. Again, langerin-expressing CD8ɑ+ splenic DCs were shown to be involved in this response by acquiring antigen and ɑ-GalCer from the injected vaccine BM-DCs. Finally, it was possible to achieve even greater CD8+ T cell responses in-vivo by injecting BM-DCs carrying antigen and ɑ-GalCer, together with timely co-administration of the TLR agonist. These results suggest a reassessment of the activities of DC-based vaccines to include the important role of “courier” to DCs already resident in the host that can be exploited to improve vaccination outcomes.</p>

2021 ◽  
Author(s):  
◽  
Dianne Sika-Paotonu

<p>Tumours can be eradicated by T cells that recognise unique tumour-associated antigens. These T cells are initially stimulated by dendritic cells (DCs) that have acquired antigens from tumour tissue. Vaccination strategies that increase the frequencies of tumour-specific T cells by enhancing the activity of DCs are being evaluated in the clinic as novel cancer therapies. Our hypothesis is that existing DC-based vaccination strategies can be improved by stimulating toll-like receptor (TLR) signalling in the DCs, and also by encouraging interactions with iNKT cells, as these two activities are known to enhance DC function. It was also hypothesised that superior T cell responses could be induced by combining these two activities together. We used the TLR 4 agonist monophosphoryl lipid A (MPL) alone and in combination with other TLR agonists to achieve effective activation of bone marrow-derived DCs (BM-DCs) cultured in-vitro, which was characterised by upregulated expression of maturation markers on the cell surface, and enhanced release of pro-inflammatory cytokines. Some TLR agonist combinations provided significantly enhanced activities in this regard, notably the combination of MPL with either the TLR 2 agonist Pam3Cys, or the TLR 7/8 agonist Resiquimod. Although in-vitro activated BM-DCs were unable to induce stronger antigen-specific CD8+ T cell responses after intravenous injection when compared to BMDCs without TLR stimulation, enhanced CD8+ T cell responses were achieved in-vivo with the co-administration of TLR ligands, implying that TLR stimulation needed to act on cells of the host. Further studies identified the langerin-expressing CD8ɑ+ splenic DC subset in the spleen as recipients of antigen that was transferred from injected cells, and that these recipients were participants in the cross-presentation and T cell priming activities driving the CD8+ T cell response after vaccination. Antigen-loaded BM-DCs carrying the NKT cell ligand ɑ-galactosylceramide (ɑ-GalCer) were found to consistently increase antigen-specific CD8+ T cell responses in-vivo, and also cytotoxic responses as seen in cytotoxic killing assays. Again, langerin-expressing CD8ɑ+ splenic DCs were shown to be involved in this response by acquiring antigen and ɑ-GalCer from the injected vaccine BM-DCs. Finally, it was possible to achieve even greater CD8+ T cell responses in-vivo by injecting BM-DCs carrying antigen and ɑ-GalCer, together with timely co-administration of the TLR agonist. These results suggest a reassessment of the activities of DC-based vaccines to include the important role of “courier” to DCs already resident in the host that can be exploited to improve vaccination outcomes.</p>


npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Mauro Di Pilato ◽  
Miguel Palomino-Segura ◽  
Ernesto Mejías-Pérez ◽  
Carmen E. Gómez ◽  
Andrea Rubio-Ponce ◽  
...  

AbstractNeutrophils are innate immune cells involved in the elimination of pathogens and can also induce adaptive immune responses. Nα and Nβ neutrophils have been described with distinct in vitro capacity to generate antigen-specific CD8 T-cell responses. However, how these cell types exert their role in vivo and how manipulation of Nβ/Nα ratio influences vaccine-mediated immune responses are not known. In this study, we find that these neutrophil subtypes show distinct migratory and motility patterns and different ability to interact with CD8 T cells in the spleen following vaccinia virus (VACV) infection. Moreover, after analysis of adhesion, inflammatory, and migration markers, we observe that Nβ neutrophils overexpress the α4β1 integrin compared to Nα. Finally, by inhibiting α4β1 integrin, we increase the Nβ/Nα ratio and enhance CD8 T-cell responses to HIV VACV-delivered antigens. These findings provide significant advancements in the comprehension of neutrophil-based control of adaptive immune system and their relevance in vaccine design.


2021 ◽  
Author(s):  
Leonardo Estrada ◽  
Didem Agac Cobanoglu ◽  
Aaron Wise ◽  
Robert Maples ◽  
Murat Can Cobanoglu ◽  
...  

Viral infections drive the expansion and differentiation of responding CD8+ T cells into variegated populations of cytolytic effector and memory cells. While pro-inflammatory cytokines and cell surface immune receptors play a key role in guiding T cell responses to infection, T cells are also markedly influenced by neurotransmitters. Norepinephrine is a key sympathetic neurotransmitter, which acts to suppress CD8 + T cell cytokine secretion and lytic activity by signaling through the beta2-adrenergic receptor (ADRB2). Although ADRB2 signaling is considered generally immunosuppressive, its role in regulating differentiation of effector T cells in response to infection has not been investigated. Using an adoptive transfer approach, we compared the expansion and differentiation of wild type (WT) to Adrb2-/- CD8 + T cells throughout the primary response to vesicular stomatitis virus (VSV) infection in vivo. We measured the dynamic changes in transcriptome profiles of antigen-specific CD8 + T cells as they responded to VSV. Within the first 7 days of infection, WT cells out-paced the expansion of Adrb2-/- cells, which correlated with reduced expression of IL-2 and the IL-2Ralpha; in the absence of ADRB2. RNASeq analysis identified over 300 differentially expressed genes that were both temporally regulated following infection and selectively regulated in WT vs Adrb2-/- cells. These genes contributed to major transcriptional pathways including cytokine receptor activation, signaling in cancer, immune deficiency, and neurotransmitter pathways. By parsing genes within groups that were either induced or repressed over time in response to infection, we identified three main branches of genes that were differentially regulated by the ADRB2. These gene sets were predicted to be regulated by specific transcription factors involved in effector T cell development, such as Tbx21 and Eomes. Collectively, these data demonstrate a significant role for ADRB2 signaling in regulating key transcriptional pathways during CD8 + T cells responses to infection that may dramatically impact their functional capabilities and downstream memory cell development.


Author(s):  
Maud Wilhelm ◽  
Amandeep Kaur ◽  
Marion Wernli ◽  
Hans H Hirsch

Abstract Background BK polyomavirus (BKPyV) remains a significant cause of premature kidney transplant failure. In the absence of effective antivirals, current treatments rely on reducing immunosuppression to regain immune control over BKPyV replication. Increasing BKPyV-specific CD8 T cells correlate with clearance of BKPyV DNAemia in kidney transplant patients. We characterized a novel approach for expanding BKPyV-specific CD8 T cells in vitro using 27mer-long synthetic BKPyV peptides, different types of antigen-presenting cells, and CD4 T cells. Methods Langerhans cells and immature or mature monocyte-derived dendritic cells (Mo-DCs) were generated from peripheral blood mononuclear cells of healthy blood donors, pulsed with synthetic peptide pools consisting of 36 overlapping 27mers (27mP) or 180 15mers (15mP). BKPyV-specific CD8 T-cell responses were assessed by cytokine release assays using 15mP or immunodominant 9mers. Results BKPyV-specific CD8 T cells expanded using 27mP and required mature Mo-DCs (P = .0312) and CD4 T cells (P = .0156) for highest responses. The resulting BKPyV-specific CD8 T cells proliferated, secreted multiple cytokines including interferon γ and tumor necrosis factor α, and were functional (CD107a+/PD1–) and cytotoxic. Conclusions Synthetic 27mP permit expanding BKPyV-specific CD8 T-cell responses when pulsing mature Mo-DCs in presence of CD4 T cells, suggesting novel and safe approaches to vaccination and adoptive T-cell therapies for patients before and after kidney transplantation.


2020 ◽  
Vol 217 (12) ◽  
Author(s):  
Isabelle C. Arnold ◽  
Mariela Artola-Boran ◽  
Alessandra Gurtner ◽  
Katrin Bertram ◽  
Michael Bauer ◽  
...  

The depletion of eosinophils represents an efficient strategy to alleviate allergic asthma, but the consequences of prolonged eosinophil deficiency for human health remain poorly understood. We show here that the ablation of eosinophils severely compromises antitumor immunity in syngeneic and genetic models of colorectal cancer (CRC), which can be attributed to defective Th1 and CD8+ T cell responses. The specific loss of GM-CSF signaling or IRF5 expression in the eosinophil compartment phenocopies the loss of the entire lineage. GM-CSF activates IRF5 in vitro and in vivo and can be administered recombinantly to improve tumor immunity. IL-10 counterregulates IRF5 activation by GM-CSF. CRC patients whose tumors are infiltrated by large numbers of eosinophils also exhibit robust CD8 T cell infiltrates and have a better prognosis than patients with eosinophillow tumors. The combined results demonstrate a critical role of eosinophils in tumor control in CRC and introduce the GM-CSF–IRF5 axis as a critical driver of the antitumor activities of this versatile cell type.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A143-A143
Author(s):  
Dharmeshkumar Patel ◽  
Dharmeshkumar Patel ◽  
Angshumala Goswami ◽  
Vitaly Balan ◽  
Zhifen Yang ◽  
...  

BackgroundThe application of CRISPR-Cas9 for personalized medicine is potentially revolutionary for the treatment of several diseases including cancer. However, the bacterial origin of the Cas9 protein raises concerns about immunogenicity. Recent ELISA-based assays detected antibodies against Cas9 from Streptococcus pyogenes (SpCas9) and Staphylococcus aureus (SaCas9) in 5–10% of sera from 343 normal healthy individuals.1,2 SpCas9-specific memory CD8 T cell responses were not demonstrated in those individuals. To date, there are no conclusive studies assessing whether CRISPR-Cas9-modified CAR-T could raise CD8 T cell-mediated immunogenicity in humans. Refuge CAR-T cell platform employs an inducible, non-gene editing, nuclease deactivated Cas9 (dCas9) to modulate gene expression in response to external stimuli such as antigen-dependent CAR signaling to suppress PD-1 expression.MethodsIn the present study, we analyzed two putative HLA-A*02:01 and two HLA-B*07:02-associated SpCas9 T cell epitopes. The candidate epitopes were derived from a prediction algorithm that incorporates T cell receptor contact residue hydrophobicity and HLA binding affinity. We engaged in-vitro sensitization (IVS) assay to identify immunogenic potential of dCas9 peptides.ResultsAutologous IVS assay of T cells in two healthy donor PBMCs identified CD8-T cell responses after two rounds of stimulation against only one HLA-A*02:01-associated Cas9 peptide (sequence NLIALSLGL) P1– while the other candidate epitopes did not elicit any response. Dextramer analysis demonstrated that 15% of CD8+ T cells were specific for P1 and ~11% of CD8+ cells produced INFG upon challenge with P1-loaded T2 cells.ConclusionsOur in-vitro sensitization assay was able to demonstrate that dCas9 epitope P1 is immunogenic and may elicit adaptive immune response against gene edited CAR-T cells. Endogenous processing and presentation of P1 and other putative epitopes by Refuge CAR-T cells are currently being analyzed.AcknowledgementsRefuge Biotechnologies Inc. Menlo Park, California, 94025Trial RegistrationN/AEthics ApprovalN/AConsentN/AReferencesSimhadri VL, McGill J, McMahon S, Wang J, Jiang H, Sauna ZE. Prevalence of Pre-existing Antibodies to CRISPR-Associated Nuclease Cas9 in the USA Population. Mol Ther Methods Clin Dev 2018;10:105–112. Published 2018 Jun 15. doi:10.1016/j.omtm.2018.06.006Ferdosi SR, Ewaisha R, Moghadam F, et al. Multifunctional CRISPR-Cas9 with engineered immunosilenced human T cell epitopes. Nat Commun2019;10(1):1842. Published 2019 Apr 23. doi:10.1038/s41467-019-09693-x


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 318-318 ◽  
Author(s):  
Lequn Li ◽  
Hui Wang ◽  
Vassiliki A. Boussiotis

Abstract Cell cycle re-entry of quiescent T lymphocytes is required for generation of productive T cell responses. Cyclin-dependent kinases (cdk), particularly cdk2, have an essential role in cell cycle re-entry. Cdk2 promotes phosphorylation of Rb and related pocket proteins thereby reversing their ability to sequester E2F transcription factors. Besides Rb, cdk2 phosphorylates Smad2 and Smad3. Smad3 inhibits cell cycle progression from G1 to S phase, and impaired phosphorylation on the cdk-mediated sites renders it more effective in executing this function. In contrast, cdk-mediated phosphorylation of Smad3 reduces Smad3 transcriptional activity and antiproliferative function. Recently, we determined that induction of T cell tolerance resulted in impaired cdk2 activity, leading to reduced levels of Smad3 phosphorylation on cdk-specific sites and increased Smad3 antiproliferative function due to upregulation of p15. We hypothesized that pharmacologic inhibition of cdk2 during antigen-mediated T cell stimulation might provide an effective strategy to control T cell expansion and induce tolerance. (R)-roscovitine (CYC202) is a potent inhibitor of cdk2-cyclin E, which in higher concentrations also inhibits other cdk-cyclin complexes including cdk7, cdk9 and cdk5. It is currently in clinical trials as anticancer drug and recently was shown to induce long-lasting arrest of murine polycystic kidney disease. We examined the effect of roscovitine on T cell responses in vitro and in vivo. We stimulated C57BL/6 T cells with anti-CD3-plus-anti-CD28 mAbs, DO11.10 TCR-transgenic T cells with OVA peptide or C57BL/6 T cells with MHC disparate Balb/c splenocytes. Addition of roscovitine in these cultures resulted in blockade of cell proliferation without induction of apoptosis. Biochemical analysis revealed that roscovitine prevented phosphorylation of cdk2, downregulation of p27, phosphorylation of Rb and synthesis of cyclin A, suggesting an effective G1/S cell cycle block. To determine whether roscovitine could also inhibit clonal expansion of activated T cells in vivo, we employed a mouse model of GvHD. Recipient (C57BL/6 x DBA/2) F1 mice were lethally irradiated and were subsequently infused with bone marrow cells and splenocytes, as source of allogeneic T cells, from parental C57BL/6 donors. Roscovitine or vehicle-control was given at the time of allogeneic BMT and on a trice-weekly basis thereafter for a total of three weeks. Administration of roscovitine protected against acute GvHD resulting in a median survival of 49 days in the roscovitine-treated group compared to 24 days in the control group (p=0.005), and significantly less weight loss. Importantly, roscovitine treatment had no adverse effects on engraftment, resulting in full donor chimerism in the treated mice. To examine whether tolerance had been induced by in vivo treatment with roscovitine, we examined in vitro rechallenge responses. While control C57BL/6 T cells exhibited robust responses when stimulated with (C57BL/6 x DBA/2) F1 splenocytes, responses of T cells isolated from roscovitine-treated recipients against (C57BL/6 x DBA/2) F1 splenocytes were abrogated. These results indicate that roscovitine has direct effects on preventing TCR-mediated clonal expansion in vitro and in vivo and may provide a novel therapeutic approach for control of GvHD.


2009 ◽  
Vol 37 (2) ◽  
pp. 256-265 ◽  
Author(s):  
Cara K. Fraser ◽  
Stephen J. Blake ◽  
Kerrilyn R. Diener ◽  
A. Bruce Lyons ◽  
Michael P. Brown ◽  
...  

2004 ◽  
Vol 72 (12) ◽  
pp. 7240-7246 ◽  
Author(s):  
Marion Pepper ◽  
Florence Dzierszinski ◽  
Amy Crawford ◽  
Christopher A. Hunter ◽  
David Roos

ABSTRACT The study of the immune response to Toxoplasma gondii has provided numerous insights into the role of T cells in resistance to intracellular infections. However, the complexity of this eukaryote pathogen has made it difficult to characterize immunodominant epitopes that would allow the identification of T cells with a known specificity for parasite antigens. As a consequence, analysis of T-cell responses to T. gondii has been based on characterization of the percentage of T cells that express an activated phenotype during infection and on the ability of these cells to produce cytokines in response to complex mixtures of parasite antigens. In order to study specific CD4+ T cells responses to T. gondii, recombinant parasites that express a truncated ovalbumin (OVA) protein, in either a cytosolic or a secreted form, were engineered. In vitro and in vivo studies reveal that transgenic parasites expressing secreted OVA are able to stimulate T-cell receptor-transgenic OVA-specific CD4+ T cells to proliferate, express an activated phenotype, and produce gamma interferon (IFN-γ). Furthermore, the adoptive transfer of OVA-specific T cells into IFN-γ−/− mice provided enhanced protection against infection with the OVA-transgenic (but not parental) parasites. Together, these studies establish the utility of this transgenic system to study CD4+-T-cell responses during toxoplasmosis.


2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi93-vi93
Author(s):  
Matthias Gromeier ◽  
Mubeen Mosaheb ◽  
Elena Dobrikova ◽  
Michael Brown ◽  
Darell Bigner ◽  
...  

Abstract Options for the immunotherapy of diffuse intrinsic pontine glioma (DIPG), due to its anatomical location and inherent therapy resistance, are limited. The histone 3.3(K27M) mutation in ~80% of such tumors offers a unique opportunity for immunotherapy intervention, as it defines a high affinity, HLA-A2-restricted tumor neoantigen that spontaneously elicits CD8+ T cell responses in DIPG patients. Immunizing against the H3.3(K27M) signature in the clinic has been challenging, as conventional approaches (i.e. peptide-conjugates administered with adjuvants) lack the costimulatory signals known to drive CD8+ effector T cell responses. Therefore, we built on a viral vector approach for engaging innate immune responses to virus infection specifically in antigen presenting cells. Viruses naturally engage innate immunity, induce antigen presentation, and mediate CD8 T cell priming against foreign antigens. Polioviruses can provide a context optimal for generating antigen-specific CD8 T cells, as they have natural tropism for dendritic cells, preeminent inducers of CD8 T cell immunity; elicit Th1-promoting inflammation; and lack interference with innate or adaptive immunity. However, notorious genetic instability and underlying neuropathogenicity has hampered poliovirus-based vector applications. We devised a strategy based on the polio:rhinovirus chimera PVSRIPO, devoid of viral neuropathogenicity after intracerebral inoculation in human subjects, for stable expression of exogenous antigens. PVSRIPO vectors infect, activate, and induce epitope presentation in DCs in vitro; recruit and activate DCs with Th1-dominant cytokine profiles at the injection site in vivo. They efficiently prime tumor antigen-specific CD8 T cells in vivo, induce CD8 T cell migration to the tumor site, delay tumor growth and enhance survival in syngeneic rodent tumor models. We are preparing a prototype PVSRIPO-derived vector delivering the H3.3(K27M) signature for clinical investigation.


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