PGE2-EP4 signaling steers cDC2 maturation toward the induction of suppressive T-cell responses.

Dendritic cells (DCs) shape adaptive immunity in response to environmental cues such as cytokines or lipid mediators, including prostaglandin E2 (PGE2). In cancer, tumors are known to establish an enriched PGE2 microenvironment. Tumor-derived PGE2 primes regulatory features across immune cells, including DCs, facilitating tumor progression. PGE2 shapes DC function by providing signaling via its two so-called E-prostanoid receptors (EPs) EP2 and EP4. Although studies with monocyte-derived DCs have shown the importance of PGE2 signaling, the role of PGE2-EP2/EP4 on conventional DCs type 2 (cDC2s), is still poorly defined. In this study, we investigated the function of EP2 and EP4 using specific EP antagonists on human cDC2s. Our results show that EP2 and EP4 exhibit different functions in cDC2s, with EP4 modulating the upregulation of activation markers (CD80, CD86, CD83, MHC class II) and the production of IL-10 and IL-23. Furthermore, PGE2-EP4 boosts CCR type 7-based migration as well as a higher T-cell expansion capacity, characterized by the enrichment of suppressive rather than pro-inflammatory T-cell populations. Our findings are relevant to further understanding the role of EP receptors in cDC2s, underscoring the benefit of targeting the PGE2-EP2/4 axis for therapeutic purposes in diseases such as cancer.

Detection of dendritic cell subsets in the tumor microenvironment by multiplex immunohistochemistry.

Dendritic cells (DCs) are essential in antitumor immunity. In humans, three main DC subsets are defined: two types of conventional DCs (cDC1s and cDC2s) and plasmacytoid DCs (pDCs). To study DC subsets in the tumor microenvironment (TME), it is important to correctly identify them in tumor tissues. Tumor-derived DCs are often analyzed in cell suspensions in which spatial information about DCs which can be important to determine their function within the TME is lost. Therefore, we developed the first standardized and optimized multiplex immunohistochemistry panel, simultaneously detecting cDC1s, cDC2s, and pDCs within their tissue context. We report on this panel's development, validation, and quantitative analysis. A multiplex immunohistochemistry panel consisting of CD1c, CD303, X-C motif chemokine receptor 1, CD14, CD19, a tumor marker, and DAPI was established. The ImmuNet machine learning pipeline was trained for the detection of DC subsets. The performance of ImmuNet was compared with conventional cell phenotyping software. Ultimately, frequencies of DC subsets within several tumors were defined. In conclusion, this panel provides a method to study cDC1s, cDC2s, and pDCs in the spatial context of the TME, which supports unraveling their specific roles in antitumor immunity.

cDC2 plasticity and acquisition of a DC3-like phenotype mediated by IL-6 and PGE2 in a patient-derived colorectal cancer organoids model.

Metastatic colorectal cancer (CRC) is highly resistant to therapy and prone to recur. The tumor-induced local and systemic immunosuppression allows cancer cells to evade immunosurveillance, facilitating their proliferation and dissemination. Dendritic cells (DCs) are required for the detection, processing, and presentation of tumor antigens, and subsequently for the activation of antigen-specific T cells to orchestrate an effective antitumor response. Notably, successful tumors have evolved mechanisms to disrupt and impair DC functions, underlining the key role of tumor-induced DC dysfunction in promoting tumor growth, metastasis initiation, and treatment resistance. Conventional DC type 2 (cDC2) are highly prevalent in tumors and have been shown to present high phenotypic and functional plasticity in response to tumor-released environmental cues. This plasticity reverberates on both the development of antitumor responses and on the efficacy of immunotherapies in cancer patients. Uncovering the processes, mechanisms, and mediators by which CRC shapes and disrupts cDC2 functions is crucial to restoring their full antitumor potential. In this study, we use our recently developed 3D DC-tumor co-culture system to investigate how patient-derived primary and metastatic CRC organoids modulate cDC2 phenotype and function. We first demonstrate that our collagen-based system displays extensive interaction between cDC2 and tumor organoids. Interestingly, we show that tumor-corrupted cDC2 shift toward a CD14+ population with defective expression of maturation markers, an intermediate phenotype positioned between cDC2 and monocytes, and impaired T-cell activating abilities. This phenotype aligns with the newly defined DC3 (CD14+ CD1c+ CD163+) subset. Remarkably, a comparable population was found to be present in tumor lesions and enriched in the peripheral blood of metastatic CRC patients. Moreover, using EP2 and EP4 receptor antagonists and an anti-IL-6 neutralizing antibody, we determined that the observed phenotype shift is partially mediated by PGE2 and IL-6. Importantly, our system holds promise as a platform for testing therapies aimed at preventing or mitigating tumor-induced DC dysfunction. Overall, our study offers novel and relevant insights into cDC2 (dys)function in CRC that hold relevance for the design of therapeutic approaches.

Myeloid-derived suppressor cells and tolerogenic dendritic cells are distinctively induced by PI3K and Wnt signaling pathways.

Imbalanced immune responses are a prominent hallmark of cancer and autoimmunity. Myeloid cells can be overly suppressive, inhibiting protective immune responses or inactive not controlling autoreactive immune cells. Understanding the mechanisms that induce suppressive myeloid cells, such as myeloid-derived suppressor cells (MDSCs) and tolerogenic dendritic cells (TolDCs), can facilitate the development of immune-restoring therapeutic approaches. MDSCs are a major barrier for effective cancer immunotherapy by suppressing antitumor immune responses in cancer patients. TolDCs are administered to patients to promote immune tolerance with the intent to control autoimmune disease. Here, we investigated the development and suppressive/tolerogenic activity of human MDSCs and TolDCs to gain insight into signaling pathways that drive immunosuppression in these different myeloid subsets. Moreover, monocyte-derived MDSCs (M-MDSCs) generated in vitro were compared to M-MDSCs isolated from head-and-neck squamous cell carcinoma patients. PI3K-AKT signaling was identified as being crucial for the induction of human M-MDSCs. PI3K inhibition prevented the downregulation of HLA-DR and the upregulation of reactive oxygen species and MerTK. In addition, we show that the suppressive activity of dexamethasone-induced TolDCs is induced by ß-catenin-dependent Wnt signaling. The identification of PI3K-AKT and Wnt signal transduction pathways as respective inducers of the immunomodulatory capacity of M-MDSCs and TolDCs provides opportunities to overcome suppressive myeloid cells in cancer patients and optimize therapeutic application of TolDCs. Lastly, the observed similarities between generated- and patient-derived M-MDSCs support the use of in vitro-generated M-MDSCs as powerful model to investigate the functionality of human MDSCs.

Intratumoral T cell depletion following neoadjuvant chemotherapy in patients with muscle-invasive bladder cancer is associated with poor clinical outcome.

BACKGROUND: Whereas neoadjuvant cisplatin-based chemotherapy (NAC) followed by a radical cystectomy remains the standard treatment for patients with muscle-invasive bladder cancer (MIBC), increasing evidence suggests that checkpoint inhibitors, either alone or in combination with chemotherapy, are effective in the (neo)adjuvant setting. The major aim of this study was to improve our understanding of the immune-modulating effects of NAC in MIBC. METHODS: Tumor tissue of 81 patients was used, including 60 patients treated with NAC and 21 patients undergoing upfront cystectomy. Multiplex immunohistochemistry was performed to assess CD3+, CD3+CD8+, CD3+CD8-FoxP3-, CD3+FoxP3+, and CD20+ cells. Patients were classified into a favorable or unfavorable outcome group based on the development of a recurrence within a year. RESULTS: The density of intratumoral CD3+ T cells decreased following NAC in patients with a recurrence at one year, while it remained stable in patients without a recurrence (median fold change 0.6 [95CI 0.3; 1.0] versus 1.0 [95CI 0.6; 2.2]). This decrease was mainly attributable to a decrease in CD3+CD8-FoxP3- and CD3+FoxP3+ T cells and was not observed in patients with an early recurrence after upfront cystectomy. Additionally, in cystectomy tissue of patients treated with NAC, median CD3+ and CD3+CD8+ T cell densities were significantly lower in patients with versus patients without a recurrence (CD3: 261. cells/mm2 [95CI 22.4; 467.2]; CD8: 189.6 cells/mm2 [95CI 2.0;462.0]). CONCLUSION: T cell density decreases following NAC in MIBC patients with poor clinical outcome. Further research is needed to investigate whether this decrease in T cell density affects the efficacy of subsequent checkpoint inhibitors. PRéCIS: The major aim of this study was to improve our understanding of the immune-modulating effects of NAC in patients with MIBC. We reveal a decline in intratumoral CD3+ T cell density following NAC in patients with an early recurrence.

Tailored PGE2 Immunomodulation of moDCs by Nano-Encapsulated EP2/EP4 Antagonists.

Prostaglandin E2 (PGE2) is an important maturation mediator for dendritic cells (DCs). However, increased PGE2 levels in the tumor exert immunosuppressive effects on DCs by signaling through two E-Prostanoid (EP) receptors: EP2 and EP4. Blocking EP-receptor signaling of PGE2 with antagonists is currently being investigated for clinical applications to enhance anti-tumor immunity. In this study, we investigated a new delivery approach by encapsulating EP2/EP4 antagonists in polymeric nanoparticles. The nanoparticles were characterized for size, antagonist loading, and release. The efficacy of the encapsulated antagonists to block PGE2 signaling was analyzed using monocyte-derived DCs (moDCs). The obtained nanoparticles were sized between 210 and 260 nm. The encapsulation efficacy of the EP2/EP4 antagonists was 20% and 17%, respectively, and was further increased with the co-encapsulation of both antagonists. The treatment of moDCs with co-encapsulation EP2/EP4 antagonists prevented PGE2-induced co-stimulatory marker expression. Even though both antagonists showed a burst release within 15 min at 37 °C, the nanoparticles executed the immunomodulatory effects on moDCs. In summary, we demonstrate the functionality of EP2/EP4 antagonist-loaded nanoparticles to overcome PGE2 modulation of moDCs.

Metabolomic and lipidomic signatures associated with activation of human cDC1 (BDCA3+ /CD141+ ) dendritic cells.

Dendritic cells (DCs) bridge the connection between innate and adaptive immunity. DCs present antigens to T cells and stimulate potent cytotoxic T-cell responses. Metabolic reprogramming is critical for DC development and activation; however, metabolic adaptations and regulation in DC subsets remains largely uncharacterized. Here, we mapped metabolomic and lipidomic signatures associated with the activation phenotype of human conventional DC type 1, a DC subset specialized in cross-presentation and therefore of major importance for the stimulation of CD8+ T cells. Our metabolomics and lipidomic analyses showed that Toll-like receptor (TLR) stimulation altered glycerolipids and amino acids in cDC1. Poly I:C or pRNA stimulation reduced triglycerides and cholesterol esters, as well as various amino acids. Moreover, TLR stimulation reduced expression of glycolysis-regulating genes and did not induce glycolysis. Conversely, cDC1 exhibited increased mitochondrial content and oxidative phosphorylation (OXPHOS) upon TLR3 or TLR7/8 stimulation. Our findings highlight the metabolic adaptations required for cDC1 maturation.

Human type 1 and type 2 conventional dendritic cells express indoleamine 2,3-dioxygenase 1 with functional effects on T cell priming.

Dendritic cells (DCs) are key regulators of the immune system that shape T cell responses. Regulation of T cell induction by DCs may occur via the intracellular enzyme indoleamine 2,3-dioxygenase 1 (IDO), which catalyzes conversion of the essential amino acid tryptophan into kynurenine. Here, we examined the role of IDO in human peripheral blood plasmacytoid DCs (pDCs), and type 1 and type 2 conventional DCs (cDC1s and cDC2s). Our data demonstrate that under homeostatic conditions, IDO is selectively expressed by cDC1s. IFN-γ or TLR ligation further increases IDO expression in cDC1s and induces modest expression of the enzyme in cDC2s, but not pDCs. IDO expressed by conventional DCs is functionally active as measured by kynurenine production. Furthermore, IDO activity in TLR-stimulated cDC1s and cDC2s inhibits T cell proliferation in settings were DC-T cell cell-cell contact does not play a role. Selective inhibition of IDO1 with epacadostat, an inhibitor currently tested in clinical trials, rescued T cell proliferation without affecting DC maturation status or their ability to cross-present soluble antigen. Our findings provide new insights into the functional specialization of human blood DC subsets and suggest a possible synergistic enhancement of therapeutic efficacy by combining DC-based cancer vaccines with IDO inhibition.

PD-L1 in gestational trophoblastic disease: an antibody evaluation.

INTRODUCTION: Treatment with antibodies directed against programed-cell death ligand 1 (PD-L1) is a novel therapy for patients with gestational trophoblastic disease. Assessment of PD-L1 expression in tumor tissue is commonly used to identify patients who might benefit from anti-PD-L1 treatment. Multiple antibodies are available to detect PD-L1-expressing cells, and percentages of PD-L1-expressing cells in samples of patients with gestational trophoblastic disease indicated by these antibodies differ substantially. This raises the question which PD-L1 antibody best reflects PD-L1 expression to select patients for treatment. MATERIAL AND METHODS: Seven commercially available antibodies for PD-L1 staining (E1L3N, 73-10, 22C3, CAL10, SP142, 28-8, SP263) were validated on Chinese hamster ovarian (CHO) cells transfected with PD-L1, PD-L2, wildtype CHO cells and tonsil tissue. Next, four complete hydatidiform moles and four choriocarcinomas were stained. Samples were independently assessed by two pathologists. RESULTS: All seven antibodies showed membranous staining in the PD-L1-transfected CHO cells. E1L3N and 22C3 scored the highest percentages of PD-L1-positive cells (70%-90% and 60%-70%, respectively). E1L3N stained the cytoplasm of non-transfected CHO cells and was excluded from analysis. The remaining six antibodies predominantly stained syncytiotrophoblast cells of both complete hydatidiform moles and choriocarcinomas. The percentage of PD-L1-stained trophoblast cells and staining intensity varied substantially per used PD-L1 antibody and between complete hydatidiform moles and choriocarcinomas. Agreement between pathologists was best with 22C3 (intraclass correlation coefficient 0.94-0.96). CONCLUSIONS: Based on staining results of the CHO cells, gestational trophoblastic disease samples and intraclass correlation coefficient, 22C3 seems the most suitable for adequate detection of PD-L1-expressing trophoblast cells. All antibodies detected PD-L1-expressing cells in the gestational trophoblastic disease samples, though with great variability, hampering comparison of results between studies in this rare disease and emphasizing the need for uniformity in detecting PD-L1-expressing cells.

Immunomodulatory aged neutrophils are augmented in blood and skin of psoriasis patients.

BACKGROUND: Neutrophil accumulation in the skin is a hallmark of psoriasis. Novel insights on neutrophil phenotypic and functional heterogeneity raise the question to what extent these cells contribute to the sustained inflammatory skin reaction. OBJECTIVE: We sought to examine the phenotype and functional properties of neutrophils in blood and skin of patients with psoriasis, and the effect of TNF-α and p40(IL-12/IL-23) antibody therapy on circulating neutrophils. METHODS: Thirty-two patients with psoriasis were enrolled in an observational study performed in 2 university hospitals. We evaluated neutrophil phenotype and function using in vitro (co)culture stimulation assays, flow cytometry, multiplex immunohistochemistry, and multispectral imaging of patient-derived blood and skin samples. RESULTS: Cluster of differentiation (CD)10pos and CD10neg neutrophils were increased in peripheral blood of patients with psoriasis. In CD10neg neutrophils, different maturation stages were observed, including a subset resembling aged neutrophils that was 3 times more abundant than in healthy individuals. These aged neutrophils displayed suboptimal canonical neutrophil functions and induced IL-17 and IFN-γ production by T cells in vitro, mediated by neutrophil extracellular trap formation. Also, mature and aged neutrophils were present in psoriatic skin and were found in the vicinity of T cells. Upon antibody therapy, numbers of these cells in circulation decreased. CONCLUSIONS: Patients with psoriasis reveal a unique neutrophil profile in circulation, and 2 distinct neutrophil subsets are present in psoriatic skin. Targeted biological treatment may aid in the containment of sustained neutrophil-mediated inflammation.

Autologous monocyte-derived DC vaccination combined with cisplatin in stage III and IV melanoma patients: a prospective, randomized phase 2 trial.

BACKGROUND: Autologous dendritic cell (DC) vaccines can induce tumor-specific T cells, but their effect can be counteracted by immunosuppressive mechanisms. Cisplatin has shown immunomodulatory effects in vivo which may enhance efficacy of DC vaccination. METHODS: This is a prospective, randomized, open-label phase 2 study (NCT02285413) including stage III and IV melanoma patients receiving 3 biweekly vaccinations of gp100 and tyrosinase mRNA-loaded monocyte-derived DCs with or without cisplatin. Primary objectives were to study immunogenicity and feasibility, and secondary objectives were to assess toxicity and survival. RESULTS: Twenty-two stage III and 32 stage IV melanoma patients were analyzed. Antigen-specific CD8+ T cells were found in 44% versus 67% and functional T cell responses in 28% versus 19% of skin-test infiltrating lymphocytes in patients receiving DC vaccination with and without cisplatin, respectively. Four patients stopped cisplatin because of toxicity and continued DC monotherapy. No therapy-related grade 3 or 4 adverse events occurred due to DC monotherapy. During combination therapy, one therapy-related grade 3 adverse event, decompensated heart failure due to fluid overload, occurred. The clinical outcome parameters did not clearly suggest significant differences. CONCLUSIONS: Combination of DC vaccination and cisplatin in melanoma patients is feasible and safe, but does not seem to result in more tumor-specific T cell responses or improved clinical outcome, when compared to DC vaccination monotherapy.

What does cell therapy manufacturing cost? A framework and methodology to facilitate academic and other small-scale cell therapy manufacturing costings.

BACKGROUND AIMS: Recent technical and clinical advances with cell-based therapies (CBTs) hold great promise in the treatment of patients with rare diseases and those with high unmet medical need. Currently the majority of CBTs are developed and manufactured in specialized academic facilities. Due to small scale, unique characteristics and specific supply chain, CBT manufacturing is considered costly compared to more conventional medicinal products. As a result, biomedical researchers and clinicians are increasingly faced with cost considerations in CBT development. The objective of this research was to develop a costing framework and methodology for academic and other small-scale facilities that manufacture cell-based therapies. METHODS: We conducted an international multi-center costing study in four facilities in Europe using eight CBTs as case studies. This study includes costs from cell or tissue procurement to release of final product for clinical use. First, via interviews with research scientists, clinicians, biomedical scientists, pharmacists and technicians, we designed a high-level costing framework. Next, we developed a more detailed uniform methodology to allocate cost items. Costs were divided into steps (tissue procurement, manufacturing and fill-finish). The steps were each subdivided into cost categories (materials, equipment, personnel and facility), and each category was broken down into facility running (fixed) costs and operational (variable) costs. The methodology was tested via the case studies and validated in developer interviews. Costs are expressed in 2018 euros (€). RESULTS: The framework and methodology were applicable across facilities and proved sensitive to differences in product and facility characteristics. Case study cost estimates ranged between €23 033 and €190 799 Euros per batch, with batch yield varying between 1 and 88 doses. The cost estimations revealed hidden costs to developers and provided insights into cost drivers to help design manufacturing best practices. CONCLUSIONS: This framework and methodology provide step-by-step guidance to estimate manufacturing costs specifically for cell-based therapies manufactured in academic and other small-scale enterprises. The framework and methodology can be used to inform and plan cost-conscious strategies for CBTs.

Eight-Color Multiplex Immunohistochemistry for Simultaneous Detection of Multiple Immune Checkpoint Molecules within the Tumor Microenvironment.

Therapies targeting immune checkpoint molecules CTLA-4 and PD-1/PD-L1 have advanced the field of cancer immunotherapy. New mAbs targeting different immune checkpoint molecules, such as TIM3, CD27, and OX40, are being developed and tested in clinical trials. To make educated decisions and design new combination treatment strategies, it is vital to learn more about coexpression of both inhibitory and stimulatory immune checkpoints on individual cells within the tumor microenvironment. Recent advances in multiple immunolabeling and multispectral imaging have enabled simultaneous analysis of more than three markers within a single formalin-fixed paraffin-embedded tissue section, with accurate cell discrimination and spatial information. However, multiplex immunohistochemistry with a maximized number of markers presents multiple difficulties. These include the primary Ab concentrations and order within the multiplex panel, which are of major importance for the staining result. In this article, we report on the development, optimization, and application of an eight-color multiplex immunohistochemistry panel, consisting of PD-1, PD-L1, OX40, CD27, TIM3, CD3, a tumor marker, and DAPI. This multiplex panel allows for simultaneous quantification of five different immune checkpoint molecules on individual cells within different tumor types. This analysis revealed major differences in the immune checkpoint expression patterns across tumor types and individual tumor samples. This method could ultimately, by characterizing the tumor microenvironment of patients who have been treated with different immune checkpoint modulators, form the rationale for the design of immune checkpoint-based immunotherapy in the future.

Multicore Liquid Perfluorocarbon-Loaded Multimodal Nanoparticles for Stable Ultrasound and 19F MRI Applied to In Vivo Cell Tracking.

Ultrasound is the most commonly used clinical imaging modality. However, in applications requiring cell-labeling, the large size and short active lifetime of ultrasound contrast agents limit their longitudinal use. Here, 100 nm radius, clinically applicable, polymeric nanoparticles containing a liquid perfluorocarbon, which enhance ultrasound contrast during repeated ultrasound imaging over the course of at least 48 h, are described. The perfluorocarbon enables monitoring the nanoparticles with quantitative 19F magnetic resonance imaging, making these particles effective multimodal imaging agents. Unlike typical core-shell perfluorocarbon-based ultrasound contrast agents, these nanoparticles have an atypical fractal internal structure. The nonvaporizing highly hydrophobic perfluorocarbon forms multiple cores within the polymeric matrix and is, surprisingly, hydrated with water, as determined from small-angle neutron scattering and nuclear magnetic resonance spectroscopy. Finally, the nanoparticles are used to image therapeutic dendritic cells with ultrasound in vivo, as well as with 19F MRI and fluorescence imaging, demonstrating their potential for long-term in vivo multimodal imaging.

Early Recurrence in Completely Resected IIIB and IIIC Melanoma Warrants Restaging Prior to Adjuvant Therapy.

PURPOSE: To evaluate the results of restaging completely resected stage IIIB/C melanoma prior to start of adjuvant therapy. PATIENTS AND METHODS: One hundred twenty patients with stage IIIB or IIIC (AJCC 2009) melanoma who underwent complete surgical resection were screened for inclusion in our trial investigating adjuvant dendritic cell therapy (NCT02993315). All patients underwent imaging to exclude local relapse or metastasis before entering the trial. The frequency of recurrent disease within 12 weeks after resection and the method of detection were investigated. RESULTS: Sixty-nine (58%) stage IIIB and 51 (43%) stage IIIC melanoma patients were screened. Median age was 54 (range 27-79) years. Twenty-two (18%) of 120 patients with completely resected stage IIIB/C melanoma had evidence of early recurrent disease, despite exclusion thereof by prior imaging. Median interval between resection and detection of relapse was 7.4 (range 4.3-10.7) weeks. Recurrence was asymptomatic in 17 (77%) patients, but metastasis was noticed by the patient or physician in 5 (23%). Eight patients with local relapse received local treatment with curative intent, and one was treated with systemic therapy. The remaining patients had distant metastasis, 1 of whom underwent resection of a solitary liver metastasis while 12 patients received systemic treatment. CONCLUSIONS: Patients with completely resected stage IIIB/C melanoma have high risk of early recurrence before start of adjuvant therapy. Restaging should be considered for high-risk melanoma patients before start of adjuvant therapy.

Naturally produced type I IFNs enhance human myeloid dendritic cell maturation and IL-12p70 production and mediate elevated effector functions in innate and adaptive immune cells.

There has recently been a paradigm shift in the field of dendritic cell (DC)-based immunotherapy, where several clinical studies have confirmed the feasibility and advantageousness of using directly isolated human blood-derived DCs over in vitro differentiated subsets. There are two major DC subsets found in blood; plasmacytoid DCs (pDCs) and myeloid DCs (mDCs), and both have been tested clinically. CD1c+ mDCs are highly efficient antigen-presenting cells that have the ability to secrete IL-12p70, while pDCs are professional IFN-α-secreting cells that are shown to induce innate immune responses in melanoma patients. Hence, combining mDCs and pDCs poses as an attractive, multi-functional vaccine approach. However, type I IFNs have been reported to inhibit IL-12p70 production and mDC-induced T-cell activation. In this study, we investigate the effect of IFN-α on mDC maturation and function. We demonstrate that both recombinant IFN-α and activated pDCs strongly enhance mDC maturation and increase IL-12p70 production. Co-cultured mDCs and pDCs additionally have beneficial effect on NK and NKT-cell activation and also enhances IFN-γ production by allogeneic T cells. In contrast, the presence of type I IFNs reduces the proliferative T-cell response. The mere presence of a small fraction of activated pDCs is sufficient for these effects and the required ratio between the subsets is non-stringent. Taken together, these results support the usage of mDCs and pDCs combined into one immunotherapeutic vaccine with broad immunostimulatory features.

Interferon Gamma-Induced Protein (IP-10) as Potential Biomarker for Cancer-Related-Fatigue: Results from a 6-month Randomized Controlled Trial.

We examined if serum concentrations Interferon gamma-induced protein (IP-10) is a potential clinical biomarker for cancer-related-fatigue (CRF). Fatigue scores and IP-10 concentrations were measured from curatively treated fatigued cancer patients randomized to either cognitive behavioral therapy (CBT, n = 26) or waiting-list (WL, n = 13). No correlation was found between baseline IP-10 level and fatigue severity and no significant differences in IP-10 serum levels were observed between fatigued and matched non-fatigued patients (n = 22). Relative changes in IP-10 concentrations from baseline to six-month follow-up were not significantly different between the CBT and WL conditions. In this study, IP-10 showed low potential as clinical CRF biomarker. TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov (NCT01096641).

Different Lipid Regulation in Ovarian Cancer: Inhibition of the Immune System.

Lipid metabolism is altered in several cancer settings leading to different ratios of intermediates. Ovarian cancer is the most lethal gynecological malignancy. Cancer cells disperse in the abdominal space and ascites occurs. T cells obtained from ascites are unable to proliferate after an antigenic stimulus. The proliferation of ascites-derived T cells can be restored after culturing the cells for ten days in normal culture medium. No pathway aberrancies were detected. The acellular fraction of ascites can inhibit the proliferation of autologous as well as allogeneic peripheral blood lymphocytes, indicating the presence of soluble factors that interfere with T cell functionality. Therefore, we analyzed 109 lipid mediators and found differentially regulated lipids in suppressive ascitic fluid compared to normal abdominal fluid. Our study indicates the presence of lipid intermediates in ascites of ovarian cancer patients, which coincidences with T cell dysfunctionality. Since the immune system in the abdominal cavity is compromised, this may explain the high seeding efficiency of disseminated tumor cells. Further research is needed to fully understand the correlation between the various lipids and T cell proliferation, which could lead to new treatment options.

Multispectral imaging for highly accurate analysis of tumour-infiltrating lymphocytes in primary melanoma.

AIMS: The quality and quantity of the infiltration of immune cells into tumour tissues have substantial impacts on patients' clinical outcomes, and are associated with response to immunotherapy. Therefore, the precise analysis of tumour-infiltrating lymphocytes (TILs) is becoming an important additional pathological biomarker. Analysis of TILs is usually performed semiquantitatively by pathologists on haematoxylin and eosin-stained or immunostained tissue sections. However, automated quantification outperforms semiquantitative approaches, and is becoming the standard. Owing to the presence of melanin pigment, this approach is seriously hampered in melanoma, because the spectrum of melanin lies close to that of commonly used immunohistochemical stains. Aim of this study is to overcome the technical issues due to the presence of melanin for an automated and accurate quantification of TILs in melanoma. METHODS AND RESULTS: Here, we successfully applied a novel multispectral imaging (MSI) technique to enumerate T cells in human primary melanomas. This microscopy technique combines imaging with spectroscopy to obtain both quantitative expression data and the tissue distributions of different cellular markers. We demonstrate that MSI allows complete and accurate analysis of TILs, successfully avoiding the blurring of images by melanin pigments, in whole tissue slide primary melanoma lesions, which could otherwise not be accurately detected by conventional digital image methodologies. CONCLUSIONS: Our study highlights the potential of MSI for accurate assessment of immune cell infiltrates, including those in notoriously difficult tissues, such as pigmented melanomas. Quantification of tumour infiltration by different immune cell types is crucial in the search for new biomarkers to predict patient responses to immunotherapies. Our findings show that this innovative microscopy technique is an important extension of the armamentarium of pathologists.

Tumoricidal activity of human dendritic cells.

Dendritic cells (DCs) are a family of professional antigen-presenting cells (APCs) that are able to initiate innate and adaptive immune responses against pathogens and tumor cells. The DC family is heterogeneous and is classically divided into two main subsets, each with its unique phenotypic and functional characteristics: myeloid DCs (mDCs) and plasmacytoid DCs (pDCs). Recent results have provided intriguing evidence that both DC subsets can also function as direct cytotoxic effector cells; in particular, against cancer cells. In this review, we delve into this understudied function of human DCs and discuss why these so-called killer DCs might become important tools in future cancer immunotherapies.