Project description:The process of cancer immunosurveillance is a mechanism of tumour suppression that can protect the host from cancer development throughout its lifetime1,2. However, it is unknown whether the effectiveness of cancer immunosurveillance fluctuates over a single day. Here we demonstrate that the initial time of day of tumour engraftment dictates the ensuing tumour size across mouse cancer models. Using immunodeficient mice as well as mice lacking lineage-specific circadian functions, we show that dendritic cells (DCs) and CD8+ T cells exert circadian anti-tumour functions that control melanoma volume. Specifically, we find that rhythmic trafficking of DCs to the tumour draining lymph node governs a circadian response of tumour-antigen-specific CD8+ T cells that is dependent on the circadian expression of the co-stimulatory molecule CD80. As a consequence, cancer immunotherapy is more effective when synchronized with DC functions, shows circadian outcomes in mice and suggests similar effects in humans. These data demonstrate that the circadian rhythms of anti-tumour immune components are not only critical for controlling tumour size but can also be of therapeutic relevance.
Project description:The adaptive immune response is under circadian control, yet, the benefit of this rhythmicity for the organism is unknown. Furthermore, it is not understood why adaptive immune reactions continue to exhibit circadian changes over long periods of time. Using a combination of experimental and mathematical modelling approaches, we show here that dendritic cells (DCs) migrate from the skin to the draining lymph node (LN) in a time-of-day-dependent manner, which provides an enhanced likelihood for functional interactions with T cells. Greater numbers of infiltrating DCs induce rhythmic expression of TNF-α in the draining LN, which enhances ICAM-1 expression in high endothelial venules (HEVs), resulting in lymphocyte infiltration and LN expansion. Icam1 is controlled by binding of the core circadian clock transcription factor BMAL1 to its promoter region, and rhythmic Icam1 expression is lost in mice lacking endothelial cell BMAL1. LN cellularity continues to be different for weeks after the initial time-of-day-dependent challenge, which determines the immune response to vaccinations directed against Hepatitis A virus as well as SARS-CoV-2, as evidenced by rhythmic T cell reactions, germinal center formation and antibody production. Our results provide the mechanistic understanding of the time-of-day dependent development and maintenance of an adaptive immune response, demonstrating its dependency upon the timing of the initial challenge and the interactions of rhythmicity in multiple parameters. This provides a strategy for using time-of-day to optimize vaccination regimes.
Project description:Analyses of gene expression between CD103+ lung DCs, CD24+ lung DCs and CD64+ lung macrophages in Specific pathogen free (SPF) and germ free (GF) mice. Hypothesis tested was that the IgA class switching function of lung DCs is regulated by genes differentially expressed in GF mice compared to SPF mice. Results obtained provide important insights into the mechanisms of IgA induction by lung DCs
Project description:We report that Klebsiella pneumoniae promote Th1 cell induction in colon. To examine the influence of Klebsiella on colonic epithelial cells (ECs) and lamina propria CD11c+ dendritic cells (DCs), we performed RNA seq on them. Germ free mice were orally inoculated with Kp-2H7 or BAA-2552 and total RNA was isolated from colonic ECs and DCs 1 week after inoculation. Furthermore, we examined the involvement of TLRs in induction of Th1 cells using Myd88 KO, Trif KO, Myd88/Trif DKO mice. These deficient germ free mice were orally inoculated with Kp-2H7 and total RNA was isolated from colonic ECs 3 weeks after inoculation.
Project description:Ectopic expression of transcription factors has been used to reprogram differentiated somatic cells toward pluripotency or to directly reprogram them to other somatic cell lineages. This concept has been explored in the context of regenerative medicine. Here, we set out to generate dendritic cells (DCs) capable of presenting antigens from mouse and human fibroblasts. By screening combinations of 18 transcription factors that are expressed in DCs, we have identified PU.1, IRF8, and BATF3 transcription factors as being sufficient to reprogram both mouse and human fibroblasts to induced DCs (iDCs). iDCs acquire a conventional DC type 1–like transcriptional program, with features of interferon-induced maturation. iDCs secrete inflammatory cytokines and have the ability to engulf, process, and present antigens to T cells. Furthermore, we demonstrate that murine iDCs generated here were able to cross-present antigens to CD8+ T cells. Our reprogramming system should facilitate better understanding of DC specification programs and serve as a platform for the development of patient-specific DCs for immunotherapy.
Project description:Scarcity of dendritic cells (DCs) impact lung and pancreatic tumor immune status despite limited clinical benefits from autologous tumor lysate-pulsed DC vaccination. To tackle this issue, we developed a DC-based immunotherapy utilizing cationic nanoparticles (cNPs) loaded with tumor or organoid lysate encapsulated within DC-derived microvesicles (cNPcancer cell@MVDC). Remarkably, cNPcancer cell@MVDC treatment converted immune cold tumors into a hot microenvironment, leading to increased migratory DC population, reduced tumor growth and improved survival in orthotopic animal models compared to mature DC treatment. In vivo tracking experiments demonstrated superior accumulation of cNPcancer cell@MVDC in tumors and draining lymph nodes (dLNs) compared to mature DCs, promoting DC migration to dLNs and activating CD8+ T cells. Clinically, the accurate prediction of tumor immune status, immunotherapy response and patient prognosis relies on migratory DC infiltration rather than CD8+ T cells. Mechanistically, tumor lysate pulsed-cNPs enriched mitochondrial DNA, which exhibited a stronger binding affinity with cGAS compared to nuclear DNA, resulting in enhanced cGAS-STING-mediated DC activation. This immunotherapy elicits durable anti-tumor immune responses, even in immune-deserted tumor environments.
Project description:Dendritic cells (DCs) are the professional antigen-presenting cells of the immune system. As such they are currently used in clinical vaccination protocols in cancer patients. We evaluate the ability of mature DCs pulsed with carcinoembryonic antigen (CEA)-peptide (arm A) or electroporated with CEA-mRNA (arm B) to induce CEA-specific T cell responses in patients with resectable liver metastases from colorectal cancer. To evaluate immune responses, CEA-specific T cell reactivity is monitored in peripheral blood, resected abdominal lymph nodes, tumor tissue and biopsies of vaccination sites and post-treatment DTH skin tests. Patients are vaccinated intradermally and intravenously with CEA-peptide pulsed mature DCs three times prior to resection of liver metastases. In 2007 a side-study has been added (arm C), in which patients with stage III or high-risk stage II colorectal cancer that are amenable for standard adjuvant oxaliplatin/capecitabine therapy are vaccinated with CEApeptide-pulsed DCs. Also in this group, safety and immune responses in peripheral blood and the DTH-skin test are the primary endpoints. Results are compared with the results obtained in arm A.
Project description:Upon activation by the ligands Gas6 and Protein S, Tyro3/Axl/Mer (TAM) receptor tyrosine kinases promote phagocytic clearance of apoptotic cells and downregulate immune responses initiated by Toll-like receptors and type I interferons (IFNs). Many enveloped viruses display the phospholipid phosphatidylserine on their membranes, through which they bind Gas6 and Protein S and engage TAM receptors. We find that ligand-coated viruses activate TAM receptors on dendritic cells (DCs), dampen type I IFN signaling, and thereby evade host immunity and promote infection. Upon virus challenge, TAM-deficient DCs display type I IFN responses that are elevated in comparison to wild-type cells. As a consequence, TAM-deficient DCs are relatively resistant to infection by flaviviruses and pseudotyped retroviruses, but infection can be restored with neutralizing type I IFN antibodies. Correspondingly, a TAM kinase inhibitor antagonizes the infection of wild-type DCs. Thus, TAM receptors are engaged by viruses in order to attenuate type I IFN signaling and represent potential therapeutic targets.
Project description:The ability of dendritic cells (DCs) to activate immunity is linked to their maturation status. In prior studies we have shown that selective antibody-mediated blockade of inhibitory FcgRIIB receptor on human DCs in the presence of activating immunoglobulin (Ig) ligands leads to DC maturation and enhanced immunity to antibody-coated tumor cells. Here we show that Fcg receptor (FcgR) mediated activation of human monocytes and monocyte-derived DCs is associated with a distinct gene expression pattern, including several inflammation associated chemokines as well as type 1 interferon (IFN) response genes including the activation of signal transducer and activator of transcription 1 (STAT1). Experiment Overall Design: To further characterize FcgR mediated enhancement of DC function, we analyzed the gene expression profiles (GEP) of pure populations of monocyte-derived DCs from healthy donors (n=5) using Affymetrix Human Genome U133 Plus2.0 microarrays. Immature DCs cultured in 1% plasma were treated for 24 hours with either anti-FcgRIIB or isotype control antibody. To test whether FcgR mediated DC maturation was distinct from other maturation stimuli, we also compared DCs matured using the inflammatory cytokine cocktail (TNF-a, IL-1b, IL-6 and PGE2) commonly utilized in DC immunotherapy trials. In addition, we also treated Cd14+ monocytes (n=3) with anti-FcgRIIB antibody or isotype control. In order to better characterize the interferon responsive genes in DCs, we treated immature DCs (n=3) with 1000 U/ml of IFN-a2b.