Antigen-presenting Dendritic Cells Research Articles

A dual-STING-activating nanosystem expands cancer immunotherapeutic temporal window.

Stimulator of interferon genes (STING) is a promising antitumor target via bridging innate and adaptive immunity, yet the transient nature of immune signal transduction renders small-molecule agonists susceptible to short time effectiveness. Here, we report a dual-STING-activating micelle system (D-SAM) to dynamically program STING kinetics. Mechanistically, the natural ligand cGAMP encapsulated in D-SAM initiates STING signaling, while the pH-sensitive polymeric agonist PC7A disassembled from micelle shell buffers lysosomal protons and retards STING degradation. This prolonged STING activity facilitates dendritic cell (DC) antigen presentation and extends cytotoxic T lymphocyte priming. D-SAM improves efficacy over single soluble or delivered agonists against established, metastatic, and recurring murine tumors. Specific depletion of STING in DCs or blockade of CD8+ Tcell infiltration abrogates therapeutic effects. The feasibility of immune modulation is further validated in resected human patient tissues. This work underscores the temporal rhythm of STING as crucial for mounting a potent and enduring antitumor immune response.

Dendritic cell-intrinsic PTPN22 negatively regulates antitumor immunity and impacts anti-PD-L1 efficacy

BackgroundIndividuals with a loss-of-function single-nucleotide polymorphism in the gene encoding PTPN22 have an increased risk for autoimmune diseases, and patients with cancer with such alleles may respond better to checkpoint...

Cohesin-mediated chromatin remodeling controls the differentiation and function of conventional dendritic cells.

The cohesin protein complex extrudes chromatin loops, stopping at CTCF-bound sites, to organize chromosomes into topologically associated domains, yet the biological implications of this process are poorly understood. We show that cohesin is required for the post-mitotic differentiation and function of antigen-presenting dendritic cells (DCs), particularly for antigen cross-presentation and IL-12 secretion by type 1 conventional DCs (cDC1s) in vivo. The chromatin organization of DCs was shaped by cohesin and the DC-specifying transcription factor IRF8, which controlled chromatin looping and chromosome compartmentalization, respectively. Notably, optimal expression of IRF8 itself required CTCF/cohesin-binding sites demarcating the Irf8 gene. During DC activation, cohesin was required for the induction of a subset of genes with distal enhancers. Accordingly, the deletion of CTCF sites flanking the Il12b gene reduced IL-12 production by cDC1s. Our data reveal an essential role of cohesin-mediated chromatin regulation in cell differentiation and function in vivo, and its bi-directional crosstalk with lineage-specifying transcription factors.

Abstract B064: Antigen-presenting type-I conventional dendritic cells facilitate curative checkpoint blockade immunotherapy in pancreatic cancer

Abstract The link between cancers and inflammation was first made by Rudolph Virchow more than a century ago when cancers were observed at sites with chronic inflammation. The host response to cancer shares many parallels with inflammation and wound healing process.Inflammation and tissue damage associated with pancreatitis can precede or occur concurrently with pancreatic ductal adenocarcinoma (PDAC). We demonstrate that in PDAC coupled with pancreatitis (ptPDAC), antigen-presenting type-I conventional dendritic cells (cDC1s) are specifically activated. Immune checkpoint blockade therapy (iCBT) leads to cytotoxic CD8+ T cell activation and eradication of ptPDAC with restoration of lifespan even upon PDAC re-challenge. Such eradication of ptPDAC was reversed following specific depletion of dendritic cells. Employing PDAC antigen-loaded cDC1s as a vaccine, immunotherapy-resistant PDAC was rendered sensitive to iCBT with a curative outcome. Analysis of the T-cell receptor (TCR) sequences in the tumor infiltrating CD8+ T cells following cDC1 vaccination coupled with iCBT identified unique CDR3 sequences with potential therapeutic significance. Our findings identify a fundamental difference in the immune microenvironment and adaptive immune response in PDAC concurrent with, or without pancreatitis, and provides a rationale for combining cDC1 vaccination with iCBT as a potential treatment option. Citation Format: Krishnan K Mahadevan, Allison M. Dyevoich, Yang Chen, Bingrui Li, Hikaru Sugimoto, Amari Sockwell, Kathleen McAndrews, Huamin Wang, Shabnam Shalapour, Stephanie Watowich, Raghu Kalluri. Antigen-presenting type-I conventional dendritic cells facilitate curative checkpoint blockade immunotherapy in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B064.

Abstract B059: Modulating the immunosuppressive pancreas tumor microenvironment through intratumoral delivery of cytokine-encoding mRNAs

Abstract Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive cancer, with a mere 13% average 5-year survival rate. The hallmark desmoplastic stromal response in PDAC leads to poor vascularization, drug delivery challenges, and impaired cytotoxic immune cell infiltration, contributing to de novo therapy resistance. Our previous research has shown therapeutic induction of cellular senescence with RAS pathway targeting therapies can induce cytokine and chemokine production through the senescence-associated secretory phenotype (SASP) that can effectively activate anti-tumor T cell immunity and responses to anti-PD-1 immune checkpoint blockade. To build on these findings as well as overcome limitations associated with senescence-inducing therapy toxicity and induction of pro-tumorigenic SASP cytokines, here we leveraged mRNA technology to deliver specific SASP cytokines and chemokines we have found to stimulate immune responses directly into the suppressive PDAC TME as an immune oncology platform. We created an in vitro transcription pipeline for mRNA production and multiplexing, and demonstrate we can intratumorally deliver multiple mRNAs simultaneously into the TME of transplanted and autochthonous PDAC mouse models, stimulating the local production of cytokines normally absent in PDAC. We further characterized a novel combination of five cytokines and chemokines that can effectively recruit and activate both innate and adaptive immune responses against PDAC. Through repeated bi-weekly dosing, this mRNA combination also promotes tumor destruction and improves survival outcomes. Considering the recent success of off-the-shelf neoantigen mRNA vaccines in early human PDAC patient trials, we have now developed mRNAs that encode PDAC-specific antigens. By integrating our cytokine mRNA platform with antigen mRNAs, we observe a significant increase in intratumoral antigen-presenting dendritic cell populations and a substantially enhanced T-cell mediated anti- tumor immune response in orthotopic transplant models of PDAC. Overall, this study not only unveils pivotal insights into the cytokines absent in PDAC that are crucial for promoting anti- tumor immunity, but also pioneers an innovative immunotherapy approach. This platform has the potential to be integrated with existing immunotherapy modalities, addressing the longstanding challenge of therapy resistance in PDAC. Citation Format: Chaitanya Naimesh Parikh, Kelly De Marco, Katherine Murphy, Loretah Chibaya, Lin Zhou, Youwei Qiao, Griffin Kane, Li Li, Wen Xue, Marcus Ruscetti. Modulating the immunosuppressive pancreas tumor microenvironment through intratumoral delivery of cytokine-encoding mRNAs [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B059.

A dual-pathway pyroptosis inducer based on Au–Cu2-xSe@ZIF-8 enhances tumor immunotherapy by disrupting the zinc ion homeostasis

The regulation of intracellular ionic homeostasis to trigger antigen-specific immune responses has attracted extensive interest in tumor therapy. In this study, we developed a dual-pathway nanoreactor, Au-Cu2-xSe@ZIF-8@P18 NPs (ACS-Z-P NPs), which targets danger-associated molecular patterns (DAMPs) and releases Zn2+ and reactive oxygen species (ROS) within the tumor microenvironment (TME). Zn2+ released from the metal–organic frameworks (MOFs) was deposited in the cytoplasm, leading to aberrant transcription levels of intracellular zinc-regulated proteins and DNA damage, thereby inducing pyroptosis and immunogenic cell death (ICD) dependent on caspase1/gasdermin D (GSDMD) pathway. Furthermore, upon laser irradiation, ACS-Z-P NPs could break through the limitations of inherent defects of immunosuppression in TME, enhance ROS generation through a Fenton-like reaction cascade, which subsequently triggered the activation of inflammatory vesicles and the release of damage-associated molecular patterns (DAMPs). This cascade effect led to the amplification of pyroptosis and immunogenic cell death (ICD), thereby remodeling the immunosuppressed TME. Consequently, this process improved dendritic cell (DC) antigen presentation and augmented anti-tumor T-cell responses, effectively initiating antigen-specific immune responses and further enhancing pyroptosis and ICD. This study explores the therapeutic properties of these mechanisms in detail. Statement of significanceThe synthesized Au-Cu2-xSe@ZIF-8@P18 nanoparticles (ACS-Z-Ps) can effectively enhance the bodyʼs immune response by regulating zinc ion levels within cells. This regulation leads to abnormal levels of zinc-regulated protein transcription and DNA damage, which induces cellular pyroptosis. As a result, antigen presentation to dendritic cells (DCs) is improved, and anti-tumor T-cell responses are enhanced.The ACS-Z-P NPs overcome the limitations of ROS deficiency and immunosuppression in the tumor microenvironment by using H2O2 in the tumor microenvironment through a Fenton-like reaction. This leads to an increased production of ROS and O2, remodeling of the immunosuppressed tumor microenvironment, and enhanced induction of cell pyroptosis and immunogenic cell death.ACS-Z-P NPs targeted B16 cells using the photosensitizer P18 in combination with PDT treatment. This approach significantly inhibited the proliferation of B16 cells and effectively inhibited tumor growth.

Glucosylated Nanovaccines for Dendritic Cell-Targeted Antigen Delivery and Amplified Cancer Immunotherapy.

Engineering nanovaccines capable of targeting dendritic cells (DCs) is desperately required to maximize antigen cross-presentation to effector immune cells, elicit strong immune responses, and avoid adverse reactions. Here, we showed that glucose transporter 1 (Glut-1) on DCs is a reliable target for delivering antigens to DCs, and thus, a versatile antigen delivery strategy using glucosylated nanovaccines was developed for DC-targeted antigen delivery and tumor immunotherapy. The developed glucosylated ovalbumin-loaded nanovaccines highly accumulated in lymph nodes and efficiently engaged with Glut-1 on DCs to accelerate intracellular antigen delivery and promote DC maturation and antigen presentation, which elicited potent antitumor immunity to prevent and inhibit ovalbumin-expressing melanoma. Moreover, immunotherapeutic experiments in DC- and macrophage-depleted animal models confirmed that the glucosylated nanovaccines functioned mainly through DCs. In addition, the neoantigen-delivering glucosylated nanovaccines were further engineered to elicit tumor-specific immune responses against MC38 tumors. This study offers a DC-targeted antigen delivery strategy for cancer immunotherapy.

Reconstitution of the Multiple Myeloma Microenvironment Following Lymphodepletion with BCMA CAR-T Therapy.

The purpose of this study was to investigate the remodeling of the multiple myeloma microenvironment after B-cell maturation antigen (BCMA)-targeted chimeric antigen receptor T (CAR-T) cell therapy. We performed single-cell RNA sequencing on paired bone marrow specimens (n = 14) from seven patients with multiple myeloma before (i.e., baseline, "day -4") and after (i.e., "day 28") lymphodepleted BCMA CAR-T cell therapy. Our analysis revealed heterogeneity in gene expression profiles among multiple myeloma cells, even those harboring the same cytogenetic abnormalities. The best overall responses of patients over the 15-month follow-up are positively correlated with the abundance and targeted cytotoxic activity of CD8+ effector CAR-T cells on day 28 after CAR-T cell infusion. Additionally, favorable responses are associated with attenuated immunosuppression mediated by regulatory T cells, enhanced CD8+ effector T-cell cytotoxic activity, and elevated type 1 conventional dendritic cell (DC) antigen presentation ability. DC re-clustering inferred intramedullary-originated type 3 conventional DCs with extramedullary migration. Cell-cell communication network analysis indicated that BCMA CAR-T therapy mitigates BAFF/GALECTIN/MK pathway-mediated immunosuppression and activates MIF pathway-mediated anti-multiple myeloma immunity. Our study sheds light on multiple myeloma microenvironment dynamics after BCMA CAR-T therapy, offering clues for predicting treatment responsivity.

Endoplasmic reticulum-targeted iridium(III) photosensitizer induces pyroptosis for augmented tumor immunotherapy

An ideal tumor treatment strategy involves therapeutic approaches that can enhance the immunogenicity of the tumor microenvironment while simultaneously eliminating the primary tumor. A cholic acid-modified iridium(III) (Ir3) photosensitizer, targeted to the endoplasmic reticulum (ER), has been reported to exhibit potent type I and type II photodynamic therapeutic effects against triple-negative breast cancer (MDA-MB-231). This photosensitizer induces pyroptotic cell death mediated by gasdermin E (GSDME) through photodynamic means and enhances tumor immunotherapy. Mechanistic studies have revealed that complex Ir3 induces characteristics of damage-related molecular patterns (DAMPs) in MDA-MB-231 breast cancer cells under light conditions. These include cell-surface calreticulin (CRT) eversion, extracellular high mobility group box 1 (HMGB1) and ATP release, accompanied by ER stress and increased reactive oxygen species (ROS). Consequently, complex Ir3 promotes dendritic cell maturation and antigen presentation under light conditions, fully activates T cell-dependent immune response in vivo, and ultimately eliminates distant tumors while destroying primary tumors. In conclusion, immune regulation and targeted intervention mediated by metal complexes represent a new and promising approach to tumor therapy. This provides an effective strategy for the development of combined targeted therapy and immunotherapy.

Pickering emulsion-guided monomeric delivery of monophosphoryl lipid A for enhanced vaccination

Immunological adjuvants are vaccine components that enhance long-lasting adaptive immune responses to weakly immunogenic antigens. Monophosphoryl lipid A (MPLA) is a potent and safe vaccine adjuvant that initiates an early innate immune response by binding to the Toll-like receptor 4 (TLR4). Importantly, the binding and recognition process is highly dependent on the monomeric state of MPLA. However, current vaccine delivery systems often prioritize improving the loading efficiency of MPLA, while neglecting the need to maintain its monomeric form for optimal immune activation. Here, we introduce a Pickering emulsion-guided MPLA monomeric delivery system (PMMS), which embed MPLA into the oil-water interface to achieve the monomeric loading of MPLA. During interactions with antigen-presenting cells, PMMS functions as a chaperone for MPLA, facilitating efficient recognition by TLR4 regardless of the presence of lipopolysaccharide-binding proteins. At the injection site, PMMS efficiently elicited local immune responses, subsequently promoting the migration of antigen-internalized dendritic cells to the lymph nodes. Within the draining lymph nodes, PMMS enhanced antigen presentation and maturation of dendritic cells. In C57BL/6 mice models, PMMS vaccination provoked potent antigen-specific CD8+ T cell-based immune responses. Additionally, PMMS demonstrated strong anti-tumor effects against E.G7-OVA lymphoma. These data indicate that PMMS provides a straightforward and efficient strategy for delivering monomeric MPLA to achieve robust cellular immune responses and effective cancer immunotherapy.

The active form of vitamin D (calcitriol) promotes CXCR5 expression during follicular helper T cell differentiation.

Follicular helper T (Tfh) cells promote B cell differentiation and antibody production in the B cell follicles of secondary lymphoid organs. Tfh cells express their signature transcription factor BCL6, interleukin (IL)-21, and surface molecules including inducible T cell costimulator, programmed cell death-1 (PD-1), and the chemokine receptor CXCR5. Migration of Tfh cells to B cell follicles largely depends on the CXCR5 expression induced by interactions with antigen-presenting dendritic cells in the T cell area. How Tfh cells acquire sufficient levels of CXCR5 expression, however, has remained unclear. Using our in vitro culture system to generate CXCR5low Tfh-like cells from naïve CD4+ T cells with IL-6 in the absence of other cell types, we found that the active form of vitamin D, calcitriol, markedly enhanced CXCR5 expression after the release from persistent T cell receptor (TCR) stimulation. CH-223191, an aryl hydrocarbon receptor antagonist, further enhanced CXCR5 expression. IL-12 but not IL-4, in place of IL-6, also supported calcitriol to enhance CXCR5 expression even before the release from TCR stimulation, whereas the cell viability sharply decreased after the release. The Tfh-like cells generated with IL-6 and calcitriol exhibited chemotaxis towards CXCL13, expressed IL-21, and helped B cells to produce IgG antibodies in vitro more efficiently than Tfh-like cells generated without added calcitriol. Calcitriol injections into antigen-primed mice increased the proportion of CXCR5+PD-1+CD4+ cells in their lymphoid organs, and enhanced T cell entry into B-cell follicles. These results suggest that calcitriol promotes CXCR5 expression in developing Tfh cells and regulates their functional differentiation.

Lactococcus lactis subsp. cremoris YRC3780 modifies function of mesenteric lymph node dendritic cells to modulate the balance of T cell differentiation inducing regulatory T cells.

The intestinal immune system plays a pivotal role in the induction of immune responses against food. In the case of T cell response, dendritic cells (DCs) are especially important. However, the regulation of immune responses to food by intestinal DCs has been poorly described. In this study, we analyzed the effect of Lactococcus lactis subsp. cremoris YRC3780, a lactic acid bacterial strain isolated from kefir, a traditional fermented milk product, on the immune responses induced by antigen presentation by intestinal DCs to T cells as well as the mechanism of action of these immunomodulatory effects. It has been shown that L. cremoris YRC3780 ameliorates the symptoms of pollinosis in both animal and human studies. CD11c+ cells from mesenteric lymph nodes (MLNs) of BALB/c mice were cultured as MLN DCs with L. cremoris YRC3780 and expression of genes inducing regulatory T cells (Tregs) was examined by qPCR. In addition, MLN DCs were cocultured with CD4+ T cells from DO11.10 transgenic mice expressing an ovalbumin (OVA)-specific TCR and the OVA antigen peptide and L. cremoris YRC3780. Induction of Tregs was examined by flow cytometry, gene expression was analyzed by DNA microarray and qPCR, and the production of cytokines was measured by ELISA. MLN DCs from TLR2-deficient mice and components of L. cremoris YRC3780 were used to examine the recognition of YRC3780 by MLN DCs. L. cremoris YRC3780 enhanced the expression of genes involved in Treg induction in MLN DCs and induced Foxp3+CD4+T cells in an MLN DC and CD4+ T-cell co-culture system. The effect on MLN DCs was likely mediated by receptors other than TLR2. Together with microarray analyses of CD4+ T cell gene expression and cytokine ELISA, it was demonstrated that L. cremoris YRC3780 promoted the induction of Th1 and Tregs, and regulated the balance of Th1/Th2 and Treg/Th17 cells involving multiple genes via the antigen-presentation of MLN DCs. Our findings provide insights into the modulation of intestinal immune responses mediated by DCs and the antiallergic effects of lactic acid bacteria.

Diverse roles of dendritic cell and regulatory T cell crosstalk in controlling health and disease.

Dendritic cells (DCs) are specialized antigen-presenting cells for lymphocytes, including regulatory T (Treg) cells, a subset of CD4+ T cells expressing CD25 and Foxp3, a transcription factor. Treg cells maintain immunological self-tolerance in mice and humans, and suppress autoimmunity and other various immune responses such as tumor immunity, transplant rejection, allergy, responses to microbes, and inflammation. Treg cell proliferation is controlled by antigen-presenting DCs. On the other hand, Treg cells suppress the function of DCs by restraining DC maturation. Therefore, the interaction between DCs and Treg cells, DC-Treg crosstalk, could contribute to controlling health and disease. We recently found that unique DC-Treg crosstalk plays a role in several conditions. First, Treg cells are expanded in ultraviolet-B (UVB)-exposed skin by interacting with DCs, and the UVB-expanded Treg cells have a healing function. Second, manipulating DC-Treg crosstalk can induce effective acquired immune responses against SARS-CoV2 antigens without adjuvants. Third, Treg cells with a special feature interact with DCs in the tumor microenvironment of human head and neck squamous cell cancer, which may contribute to the prognosis. Understanding the underlying mechanisms of DC-Treg crosstalk may provide a novel strategy to control health and disease.

CD147 regulates the formation and function of immune synapses

CD147 is a T cell activation-associated molecule which is closely involved in the formation of the immune synapse (IS). However, the precise role of CD147 in T cell activation and IS formation remains unclear. In the present study, we demonstrated that CD147 translocated to the IS upon T cell activation and was primarily distributed in the peripheral super molecular cluster (p-SMAC). The knock down of CD147 expression in T cells, but not in B cells, impaired IS formation. CD147 participated in IS formation between T cells and different types of antigen-presenting cells (APCs), including macrophages and dendritic cells. Ligation of CD147 with its monoclonal antibody (mAb) HAb18 effectively inhibited T cell activation and IL-2 secretion. CD98, a critical molecule interacting with CD147, was distributed in IS in a CD147-dependent way. Phosphorylation levels of T cell receptor (TCR) related molecules, like ZAP-70, ERK, and cJun, were down-regulated by CD147 ligation, which is crucial for the interaction of CD147 and TCR signaling transduction. CD147 is indispensable for the formation of immune synapses and plays an important role in the regulation of its function.

Autophagy‐Inducing MoO3‐x Nanowires Boost Photothermal‐Triggered Cancer Immunotherapy

AbstractAutophagy could play suppressing role in cancer therapy by facilitating release of tumor antigens from dying cells and inducing immunogenic cell death (ICD). Therefore, discovery and rational design of more effective inducers of cytotoxic autophagy is expected to develop new strategies for finding innovative drugs for precise and successful cancer treatment. Herein, we develop MoO3‐x nanowires (MoO3‐x NWs) with high oxygen vacancy and strong photothermal responsivity to ablate tumors through hyperthermia, thus promote the induction of cytotoxic autophagy and severe ICD. As expected, the combination of MoO3‐x NWs and photothermal therapy (PTT) effectively induces autophagy to promote the release of tumor antigens from the ablated cells, and induces the maturation and antigen presentation of dendritic cells (DCs), subsequently activates cytotoxic T lymphocytes (CTLs)‐mediated adaptive immunity. Furthermore, the combination treatment of MoO3‐x NWs with immune checkpoint blockade of PD‐1 could promote the tumor‐associated macrophages (TAMs) polarization into tumor‐killing M1 macrophages, inhibit infiltration of Treg cells at tumor sites, and alleviate immunosuppression in the tumor microenvironment, finally intensify the anti‐tumor activity in vivo. This study provides a strategy and preliminary elucidation of the mechanism of using MoO3‐x nanowires with high oxygen vacancy to induce autophagy and thus enhance photothermal immunotherapy.

Autophagy-Inducing MoO3-x Nanowires Boost Photothermal-Triggered Cancer Immunotherapy.

Autophagy could play suppressing role in cancer therapy by facilitating release of tumor antigens from dying cells and inducing immunogenic cell death (ICD). Therefore, discovery and rational design of more effective inducers of cytotoxic autophagy is expected to develop new strategies for finding innovative drugs for precise and successful cancer treatment. Herein, we develop MoO3-x nanowires (MoO3-x NWs) with high oxygen vacancy and strong photothermal responsivity to ablate tumors through hyperthermia, thus promote the induction of cytotoxic autophagy and severe ICD. As expected, the combination of MoO3-x NWs and photothermal therapy (PTT) effectively induces autophagy to promote the release of tumor antigens from the ablated cells, and induces the maturation and antigen presentation of dendritic cells (DCs), subsequently activates cytotoxic T lymphocytes (CTLs)-mediated adaptive immunity. Furthermore, the combination treatment of MoO3-x NWs with immune checkpoint blockade of PD-1 could promote the tumor-associated macrophages (TAMs) polarization into tumor-killing M1 macrophages, inhibit infiltration of Treg cells at tumor sites, and alleviate immunosuppression in the tumor microenvironment, finally intensify the anti-tumor activity in vivo. This study provides a strategy and preliminary elucidation of the mechanism of using MoO3-x nanowires with high oxygen vacancy to induce autophagy and thus enhance photothermal immunotherapy.

Enhanced abscopal anti-tumor response via a triple combination of thermal ablation, IL-21, and PD-1 inhibition therapy

Despite the success of immune checkpoint inhibitors (ICIs) in treating solid tumors, lots of patients remain unresponsive to this therapy. Microwave ablation (MWA) stimulates systemic adaptive immunity against tumor cells by releasing tumor antigens. Additionally, IL-21 has demonstrated importance in stimulating T-cell effector function. The combination of these three therapies—MWA, IL-21, and anti-PD-1 monoclonal antibodies (mAbs)—has yet to be explored in the context of cancer treatment.In this study, we explored the impact of thermal ablation on IL-21R expression in tumor-infiltrating lymphocytes (TILs). Subsequently, we assessed alterations in the tumor microenvironment (TME) and peripheral lymphoid organs. Additionally, we conducted a thorough examination of tumor-infiltrating CD45+ immune cells across various treatment groups using single-cell RNA sequencing (scRNA-seq). Moreover, we determined the potential anti-tumor effects of the triple combination involving MWA, IL-21, and anti-PD-1 mAbs.Our findings revealed that MWA upregulated the expression of IL-21R on various immune cells in the untreated tumors. The combination of MWA with IL-21 exhibited a robust abscopal anti-tumor effect, enhancing the effector function of CD8+ T cells and facilitating dendritic cells' maturation and antigen presentation in the untreated tumor. Notably, the observed abscopal anti-tumor effect resulting from the combination is contingent upon T-cell recirculation, indicating the reliance of systemic adaptive immunity for this treatment regimen. Additionally, the combination of MWA, IL-21, and PD-1 mAbs demonstrated profound abscopal anti-tumor efficacy. Our findings provide support for further clinical investigation into a triple combination therapy involving MWA, IL-21, and ICIs for the treatment of metastatic cancer.

Membrane-fused and mannose-targeted vesicles as immunoenhanced biomimetic nanovaccines for prevention and therapeutics of melanoma

Melanoma is a tumor sensitive to immune response and its immunotherapy has been a research hotspot in recent years. By fusion of melanoma cell membranes and bacterial exosomes through sequential extrusion, we herein design a three-in-one multi-antigenic nanovaccine, namely TBM, to rapidly target immune system. TBM can induce RAW264.7 macrophage cells to differentiate into M1 type cells to release cytotoxic cytokines. It can also promote the maturation and antigen presentation of bone marrow-derived dendritic cells, thus activating spleen T cells to kill B16F10 melanoma cells in vitro. TBM can significantly inhibit the growth and metastasis of melanoma in vivo, and prolong the lifetime of mice, suggesting the preventive effects of vaccines. Further, we integrate cell membranes from mouse melanoma tissues into a novel personalized therapeutic vaccine, namely autologous TBM (ATBM). ATBM combined with Anti PD1 can activate anti-tumor immune response and increase the survival rate of melanoma allografted mice, as supported by eukaryotic reference mRNA-Seq transcriptome sequencing. Generally, this study demonstrates the preventive and therapeutic effects of biomimetic nanovaccines against melanoma, which may be extended to design personalized tumor vaccines for all tumors with immunogenicity, showing great clinical perspectives.

The Improved Antigen Uptake and Presentation of Dendritic Cells Using Cell-Penetrating D-octaarginine-Linked PNVA-co-AA as a Novel Dendritic Cell-Based Vaccine.

Cancer immunotherapy using antigen-pulsed dendritic cells can induce strong cellular immune responses by priming cytotoxic T lymphocytes. In this study, we pulsed tumor cell lysates with VP-R8, a cell-penetrating D-octaarginine-linked co-polymer of N-vinylacetamide and acrylic acid (PNVA-co-AA), into the DC2.4 murine dendritic cell line to improve antigen uptake and then determined the anti-tumor effect in tumor-bearing mice. DC2.4 cells were pulsed with the cell lysate of EL4, a murine lymphoma cell line, and VP-R8 to generate the DC2.4 vaccine. For the in vivo study, DC2.4 cells pulsed with EL4 lysate and VP-R8 were subcutaneously injected into the inguinal lymph node to investigate the anti-tumor effect against EL4 and EL4-specific T cell immune responses. VP-R8 significantly improved antigen uptake into DC2.4 compared to conventional keyhole limpet hemocyanin (p < 0.05). The expression of MHC class I, MHC class II, and CD86 in DC2.4 cells significantly increased after pulsing tumor lysates with VP-R8 compared to other treatments (p < 0.05). The intra-lymph node injection of DC2.4 pulsed with both VP-R8 and EL4 lysate significantly decreased tumor growth compared to DC2.4 pulsed with KLH and lysates (p < 0.05) and induced tumor-infiltrating CD8T cells. The DC2.4 vaccine also remarkably increased the population of IFN-gamma-producing T cells and CTL activity against EL4 cells. In conclusion, we demonstrated that VP-R8 markedly enhances the efficiency of dendritic cell-based vaccines in priming robust anti-tumor immunity, suggesting its potential as a beneficial additive for dendritic cell-based immunotherapy.

Differences in IDO1+ dendritic cells and soluble CTLA-4 are associated with differential clinical responses to methotrexate treatment in rheumatoid arthritis.

Antigen-presenting dendritic cells (DCs) and monocytes play an essential role in rheumatoid arthritis (RA) pathogenesis, however, their tolerogenic potential remains unclear. Herein, the tolerogenic profiles of DCs are characterized in treatment-naïve RA patients to determine their role to inflammatory arthritis management. Thirty-six treatment-naïve RA patients were enrolled, of which 62% were non-responders to methotrexate (MTX) monotherapy based on disease activity score (DAS) after 6-months of therapy. DC and monocyte subset frequencies, activation (CD40, CD86, CD209 expression), and tolerogenic profile (intracellular indoleamine-2,3-dioxygenase [IDO1] and cytotoxic T lymphocyte antigen 4 [CTLA-4] expression) were examined in the baseline peripheral blood by multicolor flow-cytometry. Soluble CTLA-4 (sCTLA-4) levels in plasma were measured. DC subsets were decreased in RA compared to healthy controls (HC), and the frequency of conventional DCs (cDC) inversely correlated with inflammatory markers and improvement in disease activity. CD141+ cDC1s were the major IDO1-expressing cells. IDO1+cDC1s were reduced in RA patients compared to HC. The baseline frequency of IDO1+cDC1s inversely correlated with improvement in disease activity. CTLA-4 expression in CD1c+ cDC2s and monocytes was lower in RA patients compared to HC. Moreover, MTX-responders had a significantly lower frequency of IDO1+cDC1 cells and higher level of sCTLA-4 in the plasma compared to MTX non-responders. There was a strong predictive association of low IDO1+cDC1 cells, low sCTLA-4 and non-response to MTX. Our findings reveal altered DC and monocytes immunophenotypes that are associated with RA pathology and treatment response. The frequencies of tolerogenic IDO1+cDC1s and the low level of sCTLA-4 are strongly associated with MTX non-responsiveness and therapeutic outcome. These results suggest that investigation of the association IDO1+cDC1 and sCTLA-4 with response to treatment may be more generalizable to other autoimmune diseases.