Recruitment Of Antigen-presenting Cells Research Articles

Abstract 7144: BR0L075 (SCB01A), a microtubule inhibitor targeting the colchicine binding site, induces immunogenic cell death

Abstract BPR0L075 (also known as SCB01A in phase II clinical trial) is a novel anti-microtubule drug with potent anti-tumor and anti-angiogenic activity in vitro and in vivo. BPR0L075 inhibits tubulin polymerization (microtubule de-stabilizer) by binding to the colchicine-binding site of tubulin. We previously reported that BPR0L075 overcomes paclitaxel (microtubule stabilizer) resistance and induces vascular-disruption in vitro and in vivo. We observed that breast and ovarian cancer cells treated with BPR0L075 in vitro induced key hallmarks of immunogenic cell death (ICD). In both human and murine, ovarian (OVCAR3, ID8) and breast cancer (MDA-MB-231, 4T1) cell lines, treatment with low nanomolar concentration of BPR0L075 significantly decreased the viability of cells evidenced by SRB assay. Using a known ICD inducer mitoxantrone as a positive control, both flow cytometric analysis and immunofluorescence staining assays demonstrated that BPR0L075 treatment led to a time- and dose-dependent translocation of calreticulin, an endoplasmic reticulum chaperone protein, on the plasma membrane of dying cells which sends an “eat me” signal. The BPR0L75 treatment also led to secretion of High Mobility Group Box 1 (HMGB1), a non-histone chromatin-binding nuclear protein, as well as adenosine triphosphate (ATP) from the cell into the extracellular space using ELISA assay. These damage-associated molecular patterns (DAMPs) are known to lead to antigen-presenting cell recruitment, phagocytosis, maturation of dendritic cells, and chemotaxis. The appearance of the ICD biomarkers (calreticulin exposure, HMGB1 and ATP release) supports BPR0L075 as an ICD-inducing antimitotic agent. Further in vivo studies are warranted to delineate the effect of BPR0L075 on immune activation and recruitment of immune cells to the tumor microenvironment. Citation Format: Ayesha Bano, Xinli Liu. BR0L075 (SCB01A), a microtubule inhibitor targeting the colchicine binding site, induces immunogenic cell death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7144.

Adoptive T cell transfer and host antigen-presenting cell recruitment with cryogel scaffolds promotes long-term protection against solid tumors

Although adoptive T cell therapy provides the T cell pool needed for immediate tumor debulking, the infused T cells generally have a narrow repertoire for antigen recognition and limited ability for long-term protection. Here, we present a hydrogel that locally delivers adoptively transferred T cells to the tumor site while recruiting and activating host antigen-presenting cells with GMCSF or FLT3L and CpG, respectively. T cells alone loaded into these localized cell depots provided significantly better control of subcutaneous B16-F10 tumors than T cells delivered through direct peritumoral injection or intravenous infusion. T cell delivery combined with biomaterial-driven accumulation and activation of host immune cells prolonged the activation of the delivered T cells, minimized host T cell exhaustion, and enabled long-term tumor control. These findings highlight how this integrated approach provide both immediate tumor debulking and long-term protection against solid tumors, including against tumor antigen escape.

Abstract 6776: Spatial transcriptomics of response to tepotinib treatment in a patient with NSCLC

Abstract Background: While cancer therapies are becoming increasingly more targeted, our understanding of the genomic changes occurring during these treatments is lacking. Moreover, the tumoral heterogeneity and its spatial distribution remain important obstacles in predicting tumor evolution and treatment responses. In recent years, genomic spatial profiling techniques have shed light on this complexity by detecting gene expression changes in heterogenous tumor regions and their microenvironment over the course of treatment. Methods: Tepotinib is a highly selective and potent MET class Ib inhibitor, approved for the treatment of patients with NSCLC with MET exon 14 skipping alterations. To detect genomic changes during neoadjuvant treatment with tepotinib, a GeoMx® digital spatial profiler (DSP; Nanostring Technologies) analysis was conducted in paired baseline and on-treatment patient samples. GeoMx® DSP was performed by selecting regions of interest with nuclear, TTF-1, CD3 and CD33 morphology markers followed by next-generation sequencing (NGS) using the Cancer Transcriptome Atlas RNA panel (>1,800 cancer-related genes). Results: Following a poor response to chemotherapy, neoadjuvant tepotinib treatment was initiated in a 54-year-old female, never-smoker with NSCLC harboring a MET exon 14 alteration. Owing to a good response to tepotinib, surgical resection of the tumor was decided by the tumor board given the downgrading (from IIIB to IA1) and resulting in a major pathological response. This resection allowed spatial transcriptomics to be compared to a baseline biopsy from the same patient. MET signaling inhibition by tepotinib treatment increased immune cell infiltration in the tumor microenvironment compared to the baseline sample. This enhanced tumoral immune cell density was shown by the fluorescent morphology markers and confirmed through spatial deconvolution of the NGS results. It was further characterized by the significantly altered gene expression levels between the two samples. Gene ontology (GO) assessment of the differentially expressed genes revealed GO terms associated with tumorigenesis in the basal sample, such as cell mobility and motility, vascular epithelial growth factor production and cell communication. In turn, the tepotinib-treated tissue mainly exhibited tumor-clearing characteristics, including antigen processing and presentation through major histocompatibility complex classes I & II, T cell-mediated toxicity, and granulocyte and leukocyte activation. Conclusion: This is the first spatial genomic characterization of the effect of tepotinib on the tumor and its microenvironment in a patient with NSCLC over time. Results from this case report highlight the impact of MET inhibition by tepotinib on the tumor immune microenvironment, likely enabling the recruitment of antigen-presenting cells for tumor clearance, while reducing the expression of tumor-promoting genes. Citation Format: Manon A. Simard, Felix Geist, Carlos Cabrera, Santiago Viteri, Joachim Albers, Michael Zuehlsdorf, Niki Karachaliou. Spatial transcriptomics of response to tepotinib treatment in a patient with NSCLC. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6776.

Natural blood plasma-based hydrogels as tumor vaccines delivery systems to enhance biomimetic recruitment of antigen presenting cells for tumor immunotherapy.

Tumor vaccines can inhibit or eliminate tumors by vaccinating hosts with tumor antigens to activate antigen-specific immune responses and have gained wild attention. However, their clinical application efficacy is often comprised due to the low safety and poor efficiency of vaccine adjuvants/carriers. Specifically, the adjuvants/carriers usually could not efficiently recruit antigen presenting cells (APCs) to capture the vaccines or directly damage these cells. Therefore, ideal tumor vaccine adjuvants/carriers should effectively recruit APCs and be friendly to the cells for well keeping their bio-functions. In this work, injectable natural blood plasma hydrogel was used for the first time to encapsulate tumor antigens and adjuvant (Mn2+) for the construction of a personalized tumor vaccine. This kind of natural hydrogel with extremely high bio-safety has great potential to friendly recruit APCs in a biomimetic manner by simulating the natural degradation process of subcutaneous blood stasis. The obtained results show that the natural blood plasma hydrogel-based tumor vaccines could significantly promote the recruitment of APCs, well maintain the immuno-functions of the cells, and finally induce efficient anti-tumor immune responses. Compared with traditional tumor vaccines, this natural blood plasma-based hydrogel provides a new strategy for the development of safe and effective tumor vaccines.

Donor Macrophages Modulate Rejection After Heart Transplantation.

Cellular rejection after heart transplantation imparts significant morbidity and mortality. Current immunosuppressive strategies are imperfect, target recipient T cells, and have adverse effects. The innate immune response plays an essential role in the recruitment and activation of T cells. Targeting the donor innate immune response would represent the earliest interventional opportunity within the immune response cascade. There is limited knowledge about donor immune cell types and functions in the setting of cardiac transplantation, and no current therapeutics exist for targeting these cell populations. Using genetic lineage tracing, cell ablation, and conditional gene deletion, we examined donor mononuclear phagocyte diversity and macrophage function during acute cellular rejection of transplanted hearts in mice. We performed single-cell RNA sequencing on donor and recipient macrophages and monocytes at multiple time points after transplantation. On the basis of our imaging and single-cell RNA sequencing data, we evaluated the functional relevance of donor CCR2+ (C-C chemokine receptor 2) and CCR2- macrophages using selective cell ablation strategies in donor grafts before transplant. Last, we performed functional validation that donor macrophages signal through MYD88 (myeloid differentiation primary response protein 88) to facilitate cellular rejection. Donor macrophages persisted in the rejecting transplanted heart and coexisted with recipient monocyte-derived macrophages. Single-cell RNA sequencing identified donor CCR2+ and CCR2- macrophage populations and revealed remarkable diversity among recipient monocytes, macrophages, and dendritic cells. Temporal analysis demonstrated that donor CCR2+ and CCR2- macrophages were transcriptionally distinct, underwent significant morphologic changes, and displayed unique activation signatures after transplantation. Although selective depletion of donor CCR2- macrophages reduced allograft survival, depletion of donor CCR2+ macrophages prolonged allograft survival. Pathway analysis revealed that donor CCR2+ macrophages are activated through MYD88/nuclear factor kappa light chain enhancer of activated B cells signaling. Deletion of MYD88 in donor macrophages resulted in reduced antigen-presenting cell recruitment, reduced ability of antigen-presenting cells to present antigen to T cells, decreased emergence of allograft-reactive T cells, and extended allograft survival. Distinct populations of donor and recipient macrophages coexist within the transplanted heart. Donor CCR2+ macrophages are key mediators of allograft rejection, and deletion of MYD88 signaling in donor macrophages is sufficient to suppress rejection and extend allograft survival. This highlights the therapeutic potential of donor heart-based interventions.

Impaired Antitumor Immune Response in MYCN-amplified Neuroblastoma Is Associated with Lack of CCL2 Secretion and Poor Dendritic Cell Recruitment.

In MYCN-nonamplified neuroblastoma, CCL2 produced by neuroblastoma cells induces the recruitment of antigen-presenting cells (DCs and monocytes/macrophages), allowing infiltration by T cells, in link with CCL19 and CCL22 production, hence favoring immune responses.

Spatially Restricted T-cell Activation in Inflamed Tissues

Abstract Pathogen control requires T-cells to locate and make direct contact with antigen-presenting cells (APCs) for peripheral reactivation and delivery of effector molecules. The signals that orchestrate T-cell-APC interactions are poorly understood in inflamed peripheral tissues. Using intravital imaging (IVI), we have found that Th1 cell entry into the inflamed dermis is nucleated by perivascular CXCL10+ cellular clusters enriched for APCs. Th1 cells form more stable interactions with APCs within these clusters compared to outer regions. CXCL10+ clusters are amplified in a IFNγ-dependent manner, where CD4+ T-cell IFNγ release increases APC recruitment and CXCL10 expression. We hypothesize that these chemokine clusters serve as CXCL10 Peripheral Activation (PAC-10) niches, where Th1 cells achieve early peripheral activation away from the pathogen modulated milieu. We seek to determine the relationship between these spatially restricted PAC-10 niches, infection foci, and pathogen clearance. Using a combination of IVI, flow cytometry, and transcriptomics we characterized niche specific Th1 cells and niche cellular composition to determine if PAC-10 niches modulate Th1 cells for pathogen control. Initial studies reveal that niche specific Th1 cells have increased CD69 and IFNγ expression compared to non-niche counterparts. PAC-10 niches appear to have a spatially distinct innate cell population, likely with enhanced ability to support Th1 activation. Future studies will characterize the functional status of niche specific Th1 cells and evaluate the necessity of PAC-10 niches for pathogen control. These studies will inform therapeutic strategies to boost T-cell activation in infection or hinder activation in autoimmunity. Supported by NIH NIAID P01 AI02851 NIH NIAID R01 AI070826

NGAL Is Necessary for Antigen-Presenting Cells Recruitment and Proteinuria in the Mouse Kidney with Ureteral Obstruction

NGAL Is Necessary for Antigen-Presenting Cells Recruitment and Proteinuria in the Mouse Kidney with Ureteral Obstruction

Abstract P219: Losartan Prevents The Recruitment Of Renal M1-like Macrophages And Dendritic Cells In Medulla Of Angiotensin Ii Hypertensive Mice

Immune cells play a major role in the development and progression of hypertension. Previous studies have shown that antigen presenting cells (APCs), such as macrophages (Mø) and dendritic cells (DCs) are particularly abundant in kidney. However, the relevance of these renal APCs on hypertension and whether their distribution change during the anti-hypertensive treatment remain unknow. We evaluated whether losartan (Los) treatment changes the abundance of APCs in the renal cortex and medulla in Angiotensin (Ang) II-infused mice.Male C57BL/6 mice (8-12wo) were treated with AngII (490ng/Kg/min), AngII+Los (20mg/Kg/day) or Vehicle for 14 days (n=4-6). Systolic blood pressure (SBP) was measured by the tail cuff method, and renal cortex/medulla were isolated for the measurements of: APCs (MHC-II + :CD11c + ), DCs (APCs:F4/80 - :CD64 - /CD103 + for type-1 DCs, or APCs:F4/80 - :CD64 - :CD11b + for type-2 DCs), and M1-like Mø (APCs:F4/80 - :CD64 + :CD11b + ), by flow cytometry.Los treatment prevented the increased SBP (AngII+Los=118.8±6.4 mmHg vs. AngII=158.0±21.1 mmHg; p<0.001), and the APCs recruitment in renal cortex (AngII+Los=23.2±2.7 vs. AngII=36.0±5.9%; p<0.01) and in renal medulla (Veh=16.3±7.7; AngII=26.3±4,7; AngII+Los=14.9±3.3%; p<0.05) induced by AngII. In addition, we observed an increase of DC2 and M1-like Mø recruitments in renal medulla of AngII mice (DC2 Veh =29.0±5.0 vs. DC2 AngII =45.5±7.3%; p<0.05; M1 Veh =44.8±7.5 vs. M1 AngII =58.3±5.3%; p<0.05), which were prevented by Los treatment (DC2 AngII+Los =27.1±6.8%; p<0.05; M1 AngII+Los =47.0±3.5%; p<0.05). Interestingly, we did not observe differences between groups on M1-like Mø, and DC2 populations in renal cortex. However, Los treatment prevented the increase of DC1 on renal cortex (Veh=2.1±1.4; AngII=5.2±2.4; AngII+Los=2.1±0.8%; p<0.05), without differences between groups at medullar level.Our results show that Los treatment has a differential effect on the APCs populations in renal cortex and medulla, suggesting that renal APCs have different participations on hypertension according their microenvironment.Supported by Fondecyt #1201251 and #3201016

Abstract 1502: Pre-conditioning modifies the tumor microenvironment to enhance solid tumor CAR T cell efficacy and endogenous immunity

Abstract Chimeric antigen receptor (CAR) T cell therapy has led to impressive clinical responses in patients with hematological malignancies; however, its utility in patients with solid tumors has been limited. While CAR T cells for the treatment of advanced prostate cancer are being clinically evaluated and are anticipated to show bioactivity, their safety and the impact of the immunosuppressive tumor microenvironment (TME) have not been faithfully explored preclinically. Using a novel human prostate stem cell antigen knock-in (hPSCA-KI) immunocompetent mouse model and syngeneic murine PSCA CAR T cells, we performed analyses of normal and tumor tissues by flow cytometry, immunohistochemistry, and/or RNA sequencing. We further assessed the beneficial impact of cyclophosphamide (Cy) pre-conditioning on modifications to the immunosuppressive TME and impact on PSCA-CAR T cell safety and efficacy. We observed an in vivo requirement of Cy pre-conditioning in uncovering the efficacy of PSCA-CAR T cells in prostate and pancreas cancer models, with no observed toxicities in normal tissues with endogenous PSCA expression. This combination also dampened the immunosuppressive TME, generated pro-inflammatory myeloid and T cell signatures in tumors, and enhanced the recruitment of antigen-presenting cells, and endogenous as well as adoptively-transferred CAR T cells, resulting in long-term anti-tumor immunity. Citation Format: John P. Murad, Dileshni Tilakawardane, Anthony K. Park, Kelly T. Kennewick, Lupita S. Lopez, Hee J. Lee, Brenna J. Gittins, Wen-Chung Chang, Chau P. Tran, Catalina Martinez, Anna M. Wu, Robert E. Reiter, Tanya B. Dorff, Stephen J. Forman, Saul J. Priceman. Pre-conditioning modifies the tumor microenvironment to enhance solid tumor CAR T cell efficacy and endogenous immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1502.

A phase 2 study of talimogene laherparepvec, nivolumab, and trabectedin (TNT) in advanced sarcoma.

11567 Background: Combination trabectidin (T) and nivolumab (N) has been shown to be a safe and effective therapy in soft tissue sarcoma (STS). Intratumoral injection of talimogene laherparepvec (TVEC) has a local oncolytic effect, and increases immune response via enhanced recruitment of antigen presenting cells, and thereby cytotoxic immune response. This study aims to determine if the addition of TVEC to combination trabectedin and nivolumab is effective and safe in advanced sarcoma. Methods: Eligible patients include patients ≥ 18 years of age with locally advanced unresectable or metastatic STS, measurable disease by RECIST v1.1, and at least one accessible tumor for TVEC intratumoral injection. N (3 mg/kg i.v. q 2 weeks), T (1.2 mg/m2 i.v. q 3 weeks) and TVEC (1x10e8 PFU/ml q 2 weeks depending on tumor size) were administered. A test dose of TVEC (1x10e6 PFU/ml) was initially given, followed three weeks later by full dose TVEC. Primary endpoint: Progression-free survival (PFS); Secondary endpoints: (1) Best overall response during treatment period, (2) PFS rate at 6 and 9 months, (3) Overall survival (OS) rate at 6, 9, and 12 months, (4) Incidence of conversion from unresectable to resectable tumor, and (5) Incidence of treatment-related adverse events. Interim. Results: There were 36 evaluable subjects under the Modified Intention-to-Treat (MITT) population, having completed the first cycle of TNT and a CT or MRI scan at the 6-week follow-up period. The most common histological subtypes include leiomyosarcoma (9), liposarcoma (5), spindle cell sarcoma (3), pleomorphic sarcoma (2), Ewing’s sarcoma (2), and other (5). Median number of prior lines of therapy was 4 (range 1-8). Best Overall Response by RECIST v1.1 = 3 PR, 27 SD, 5 PD. One patient, with previously unresectable disease was taken for resection and was found to have 100% necrosis on surgical pathology. Disease control rate (CR+PR+SD) was 86.1%. The median PFS was 5.5 (range: 1-18) months; 6-month PFS rate: 62.1%. Median PFS on therapy immediately preceding this trial was 2.0 months (range = 1-14 months). There were 47 evaluable subjects for OS analysis under the Intention-to-Treat (ITT) population having received at least one dose of T and N. The median OS was 9.0 (range 0-20) months; 6-month OS rate: 73%. Safety analysis: There were 47 evaluable subjects under the ITT population. 28% of these patients experienced ³1 SAE. The most common grade 3/4 TRAEs include anemia (12), increased ALT (8), fatigue (4), thrombocytopenia (4), neutropenia (4). There were no grade 3/4 TVEC injection site reactions. 22% of patients in the MITT cohort remain on study. Conclusions: These results suggest that combination therapy with TNT appears to be as effective as standard therapy, with no new safety signals seen. Furthermore, median PFS exceeded that of the immediately preceding lines of therapy in this heavily pre-treated cohort. As data matures, further data will be reported. Clinical trial information: NCT03886311.

CCL19 variants mediate chemotactic response via CCR7 in grass carp Ctenopharyngodon idella

CC chemokine ligand 19 (CCL19) plays a key role in the regulation of immune responses including homeostasis, inflammation, and immune tolerance. In this study, two variants of CCL19 homologues (CCL19a2 and CCL19b) and CCR7 were investigated in grass carp Ctenopharyngodon idella. The three genes were widely expressed in immune tissues and could be modulated by stimulation with LPS, PHA and poly(I:C), and infection with Flavobacterium columnare and grass carp reovirus. In an in vitro chemotaxis assay, the recombinant CCL19a2 and CCL19b were active to promote the migration of HEK293 T cells expressing CCR7 and leucocytes isolated from the gills, head kidney and spleen. Moreover, their chemotactive effects were validated in vivo. We found that the cells recruited by CCL19a2 and CCl19b are mainly monocytes/macrophages expressing high levels of IL-1β, IFN-γ, colony stimulating factor 1 receptor (CSF1R) and MHC II. Our work suggests that CCL19a2 and CCl19b are involved in recruitment of antigen presenting cells in fish.

In Situ Vaccination as a Strategy to Modulate the Immune Microenvironment of Hepatocellular Carcinoma.

Hepatocellular Carcinoma (HCC) is a highly prevalent malignancy that develops in patients with chronic liver diseases and dysregulated systemic and hepatic immunity. The tumor microenvironment (TME) contains tumor-associated macrophages (TAM), cancer-associated fibroblasts (CAF), regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC) and is central to mediating immune evasion and resistance to therapy. The interplay between these cells types often leads to insufficient antigen presentation, preventing effective anti-tumor immune responses. In situ vaccines harness the tumor as the source of antigens and implement sequential immunomodulation to generate systemic and lasting antitumor immunity. Thus, in situ vaccines hold the promise to induce a switch from an immunosuppressive environment where HCC cells evade antigen presentation and suppress T cell responses towards an immunostimulatory environment enriched for activated cytotoxic cells. Pivotal steps of in situ vaccination include the induction of immunogenic cell death of tumor cells, a recruitment of antigen-presenting cells with a focus on dendritic cells, their loading and maturation and a subsequent cross-priming of CD8+ T cells to ensure cytotoxic activity against tumor cells. Several in situ vaccine approaches have been suggested, with vaccine regimens including oncolytic viruses, Flt3L, GM-CSF and TLR agonists. Moreover, combinations with checkpoint inhibitors have been suggested in HCC and other tumor entities. This review will give an overview of various in situ vaccine strategies for HCC, highlighting the potentials and pitfalls of in situ vaccines to treat liver cancer.

T cell infiltration on local CpG-B delivery in early-stage melanoma is predominantly related to CLEC9A+CD141+ cDC1 and CD14+ antigen-presenting cell recruitment

BackgroundWe previously reported CpG-B injection at the primary tumor excision site prior to re-excision and sentinel node biopsy to result in immune activation of the sentinel lymph node (SLN), increased...

Pre-conditioning modifies the TME to enhance solid tumor CAR T cell efficacy and endogenous protective immunity

Chimeric antigen receptor (CAR) T cell therapy has led to impressive clinical responses in patients with hematological malignancies; however, its effectiveness in patients with solid tumors has been limited. While CAR T cells for the treatment of advanced prostate and pancreas cancer, including those targeting prostate stem cell antigen (PSCA), are being clinically evaluated and are anticipated to show bioactivity, their safety and the impact of the immunosuppressive tumor microenvironment (TME) have not been faithfully explored preclinically. Using a novel human PSCA knockin (hPSCA-KI) immunocompetent mouse model, we evaluated the safety and therapeutic efficacy of PSCA-CAR T cells. We demonstrated that cyclophosphamide (Cy) pre-conditioning significantly modified the immunosuppressive TME and was required to uncover the efficacy of PSCA-CAR T cells in metastatic prostate and pancreas cancer models, with no observed toxicities in normal tissues with endogenous expression of PSCA. This combination dampened the immunosuppressive TME, generated pro-inflammatory myeloid and T cell signatures in tumors, and enhanced the recruitment of antigen-presenting cells, as well as endogenous and adoptively transferred T cells, resulting in long-term anti-tumor immunity.

NK Cell Interaction With Platelets and Myeloid Cells in the Tumor Milieu.

Natural killer (NK) cells recognize and kill tumor cells via germ-line encoded receptors and polarized degranulation of cytotoxic molecules, respectively. As such, NK cells help to inhibit the development of cancers. The activating receptor NKG2D induces NK cell-mediated killing of metastasizing tumor cells by recognition of the stress-induced ligands MICA, MICB, and ULBP1-6. However, platelets enable escape from this immune surveillance mechanism by obstructing the interactions between NK cells and tumor cells or by cleaving the stress-induced ligands. It is also being increasingly appreciated that NK cells play additional roles in cancer immunity, including chemokine-mediated recruitment of antigen presenting cells in the tumor microenvironment that is followed by generation of adaptive immunity. However, the NK cell interplays with dendritic cells, and macrophages are extremely complex and involve molecular interactions via NKG2D and cytokine receptors. Specifically, NKG2D-mediated chronic interaction between NK cells and tumor-infiltrating macrophages causes immune suppression by differentiating NK cells toward a dysfunctional state. Here we discuss the underlying mechanisms of NK cell control by platelets and myeloid cells with focus on NKG2D and its ligands, and provide a timely perspective on how to harness these pathways with novel immunotherapeutic approaches.

Immunostimulatory nanoparticle incorporating two immune agonists for the treatment of pancreatic tumors

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant disease, where even surgical resection and aggressive chemotherapy produce dismal outcomes. Immunotherapy is a promising alternative to conventional treatments, possessing the ability to elicit T cell-mediated killing of tumor cells and prevent disease recurrence. Immunotherapeutic approaches thus far have seen limited success in PDAC due to a poorly immunogenic and exceedingly immunosuppressive tumor microenvironment, which is enriched with dysfunctional and immunosuppressed antigen-presenting cells (APCs). We developed a highly potent immunostimulatory nanoparticle (immuno-NP) to activate and expand APCs in the tumor and induce local secretion of interferon β (IFNβ), which is a pro-inflammatory cytokine that plays a major role in APC recruitment. The effectiveness of the immuno-NP stems from its dual cargo of two synergistic immune modulators consisting of an agonist of the stimulator of interferon genes (STING) pathway and an agonist of the Toll-like receptor 4 (TLR4) pathway. We show the functional synergy of the dual-agonist cargo can be tweaked by adjusting the ratio of the two agonists loaded in the immuno-NP, leading to an increase in IFNβ production (11-fold) compared to any single agonist immuno-NP variant. Using the orthotopic murine Panc02 model of PDAC, we show that systemic administration allowed immuno-NPs to deposit into the perivascular regions of the tumor, which coincided with the APC-rich tumor areas leading to predominant uptake of immuno-NPs by APCs. The immuno-NPs were effectively taken up by a significant portion of dendritic cells in the tumor (>56%). This led to a significant expansion of APCs, resulting in an 11.5-fold increase of dendritic cells and infiltration of lymphocytes throughout the pancreatic tumor compared to untreated animals.

Microbiome-induced antigen-presenting cell recruitment coordinates skin and lung allergic inflammation

Allergic skin inflammation often presents in early childhood; however, little is known about the events leading to its initiation and whether it is transient or long-term in nature. We sought to determine the immunologic rules that govern skin inflammation in early life. Neonatal and adult mice were epicutaneously sensitized with allergen followed by airway allergen challenge. Epicutaneous application of labeled allergen allowed for determination of antigen uptake and processing by antigen-presenting cells. RNAseq and microbiome analysis was performed on skin from neonatal and adult specific pathogen-free and germ-free mice. A mixed TH2/TH17 inflammatory response in the skin and the lungs of adult mice was observed following sensitization and challenge. Comparatively, neonatal mice did not develop overt skin inflammation, but exhibited systemic release of IL-17a and a TH2-dominated lung response. Mechanical skin barrier disruption was not sufficient to drive allergic skin inflammation, although it did promote systemic immune priming. Skin of neonatal mice and adult germ-free mice was seeded with low numbers of antigen-presenting cells and impaired chemokine and alarmin production. Enhanced chemokine and alarmin production, and seeding of the skin with antigen-presenting cells capable of instructing recruited cells to elicit their effector function, was, at least in part, dependent on formation of the microbiome, and consequently contributed to the development of overt skin disease. These data shed light on the principles that underlie allergic inflammation in different tissues and highlight a window of opportunity that might exist for early-life prevention of allergic diseases.

Chemerin: A Potential Regulator of Inflammation and Metabolism for Chronic Obstructive Pulmonary Disease and Pulmonary Rehabilitation.

Chronic obstructive pulmonary disease (COPD) features chronic inflammatory reactions of both intra- and extrapulmonary nature. Moreover, COPD is associated with abnormal glucose and lipid metabolism in patients, which influences the prognosis and chronicity of this disease. Abnormal glucose and lipid metabolism are also closely related to inflammation processes. Further insights into the interactions of inflammation and glucose and lipid metabolism might therefore inspire novel therapeutic interventions to promote lung rehabilitation. Chemerin, as a recently discovered adipokine, has been shown to play a role in inflammatory response and glucose and lipid metabolism in many diseases (including COPD). Chemerin recruits inflammatory cells to sites of inflammation during the early stages of COPD, leading to endothelial barrier dysfunction, early vascular remodeling, and angiogenesis. Moreover, it supports the recruitment of antigen-presenting cells that guide immune cells as part of the body's inflammatory responses. Chemerin also regulates metabolism via activation of its cognate receptors. Glucose homeostasis is affected via effects on insulin secretion and sensitivity, and lipid metabolism is changed by increased transformation of preadipocytes to mature adipocytes through chemerin-binding receptors. Controlling chemerin signaling may be a promising approach to improve various aspects of COPD-related dysfunction. Importantly, several studies indicate that chemerin expression in vivo is influenced by exercise. Although available evidence is still limited, therapeutic alterations of chemerin activity may be a promising target of therapeutic approaches aimed at the rehabilitation of COPD patients based on exercises. In conclusion, chemerin plays an essential role in COPD, especially in the inflammatory responses and metabolism, and has a potential to become a target for, and a biomarker of, curative mechanisms underlying exercise-mediated lung rehabilitation.

Plant-derived protein bodies as delivery vehicles for recombinant proteins into mammalian cells.

The encapsulation of biopharmaceuticals into micro‐ or nanoparticles is a strategy frequently used to prevent degradation or to achieve the slow release of therapeutics and vaccines. Protein bodies (PBs), which occur naturally as storage organelles in seeds, can be used as such carrier vehicles. The fusion of the N‐terminal sequence of the maize storage protein, γ‐zein, to other proteins is sufficient to induce the formation of PBs, which can be used to bioencapsulate recombinant proteins directly in the plant production host. In addition, the immunostimulatory effects of zein have been reported, which are advantageous for vaccine delivery. However, little is known about the interaction between zein PBs and mammalian cells. To better understand this interaction, fluorescent PBs, resulting from the fusion of the N‐terminal portion of zein to a green fluorescent protein, was produced in Nicotiana benthamiana leaves, recovered by a filtration‐based downstream procedure, and used to investigate their internalization efficiency into mammalian cells. We show that fluorescent PBs were efficiently internalized into intestinal epithelial cells and antigen‐presenting cells (APCs) at a higher rate than polystyrene beads of comparable size. Furthermore, we observed that PBs stimulated cytokine secretion by epithelial cells, a characteristic that may confer vaccine adjuvant activities through the recruitment of APCs. Taken together, these results support the use of zein fusion proteins in developing novel approaches for drug delivery based on controlled protein packaging into plant PBs.