GM-CSF in the generation of dendritic cells from human blood monocyte precursors: Recent advances

Oncolytic Activity of Sindbis Virus with the Help of GM-CSF in Hepatocellular Carcinoma

Hepatocellular carcinoma is a refractory tumor with poor prognosis and high mortality. Many oncolytic viruses are currently being investigated for the treatment of hepatocellular carcinoma. Based on previous studies, we constructed a recombinant GM-CSF-carrying Sindbis virus, named SINV-GM-CSF, which contains a mutation (G to S) at amino acid 285 in the nsp1 protein of the viral vector. The potential of this mutated vector for liver cancer therapy was verified at the cellular level and in vivo, respectively, and the changes in the tumor microenvironment after treatment were also described. The results showed that the Sindbis virus could effectively infect hepatocellular carcinoma cell lines and induce cell death. Furthermore, the addition of GM-CSF enhanced the tumor-killing effect of the Sindbis virus and increased the number of immune cells in the intra-tumor microenvironment during the treatment. In particular, SINV-GM-CSF was able to efficiently kill tumors in a mouse tumor model of hepatocellular carcinoma by regulating the elevation of M1-type macrophages (which have a tumor-resistant ability) and the decrease in M2-type macrophages (which have a tumor-promoting capacity). Overall, SINV-GM-CSF is an attractive vector platform with clinical potential for use as a safe and effective oncolytic virus.

Recognition of granulocyte-macrophage colony-stimulating factor by specific S100 proteins

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic myelopoietic growth factor and proinflammatory cytokine, clinically used for multiple indications and serving as a promising target for treatment of many disorders, including cancer, multiple sclerosis, rheumatoid arthritis, psoriasis, asthma, COVID-19. We have previously shown that dimeric Ca2+-bound forms of S100A6 and S100P proteins, members of the multifunctional S100 protein family, are specific to GM-CSF. To probe selectivity of these interactions, the affinity of recombinant human GM-CSF to dimeric Ca2+-loaded forms of 18 recombinant human S100 proteins was studied by surface plasmon resonance spectroscopy. Of them, only S100A4 protein specifically binds to GM-CSF with equilibrium dissociation constant, Kd, values of 0.3-2 μM, as confirmed by intrinsic fluorescence and chemical crosslinking data. Calcium removal prevents S100A4 binding to GM-CSF, whereas monomerization of S100A4/A6/P proteins disrupts S100A4/A6 interaction with GM-CSF and induces a slight decrease in S100P affinity for GM-CSF. Structural modelling indicates the presence in the GM-CSF molecule of a conserved S100A4/A6/P-binding site, consisting of the residues from its termini, helices I and III, some of which are involved in the interaction with GM-CSF receptors. The predicted involvement of the 'hinge' region and F89 residue of S100P in GM-CSF recognition was confirmed by mutagenesis. Examination of S100A4/A6/P ability to affect GM-CSF signaling showed that S100A4/A6 inhibit GM-CSF-induced suppression of viability of monocytic THP-1 cells. The ability of the S100 proteins to modulate GM-CSF activity is relevant to progression of various neoplasms and other diseases, according to bioinformatics analysis. The direct regulation of GM-CSF signaling by extracellular forms of the S100 proteins should be taken into account in the clinical use of GM-CSF and development of the therapeutic interventions targeting GM-CSF or its receptors.

T-Lymphocytes Activated by Dendritic Cells Loaded by Tumor-Derived Vesicles Decrease Viability of Melanoma Cells In Vitro

Immunotherapy represents an innovative approach to cancer treatment, based on activating the body's own immune system to combat tumor cells. Among various immunotherapy strategies, dendritic cell vaccines hold a special place due to their ability to activate T-lymphocytes, key players in cellular immunity, and direct them to tumor cells. In this study, the influence of dendritic cells processed with tumor-derived vesicles on the viability of melanoma cells in vitro was investigated. Dendritic cells were loaded with tumor-derived vesicles, after which they were used to activate T-cells. The study demonstrated that such modified T-cells exhibit high activity against melanoma cells, leading to a decrease in their viability. Our analysis highlights the potential efficacy of this approach in developing immunotherapy against melanoma. These results provide new prospects for further research and the development of antitumor strategies based on the mechanisms of T-lymphocyte activation using tumor-derived vesicles.

Allogeneic haematopoietic cell transplants as dynamical systems: influence of early-term immune milieu on long-term T-cell recovery

Objectives

Immune recovery following haematopoietic cell transplantation (HCT) functions as a dynamical system. Reducing the duration of intense immune suppression and augmenting antigen presentation has the potential to optimise T-cell reconstitution, potentially influencing long-term outcomes.

Methods

Based on donor-derived T-cell recovery, 26 patients were adaptively randomised between mycophenolate mofetil (MMF) administered for 30-day post-transplant with filgrastim for cytokine support (MMF30 arm, N = 11), or MMF given for 15 days with sargramostim (MMF15 arm, N = 15). All patients underwent in vivo T-cell depletion with 5.1 mg kg^-1 antithymocyte globulin (administered over 3 days, Day -9 through to Day -7) and received reduced intensity 450 cGy total body irradiation (3 fractions on Day -1 and Day 0). Patients underwent HLA-matched related and unrelated donor haematopoietic cell transplantation (HCT).

Results

Clinical outcomes were equivalent between the two groups. The MMF15 arm demonstrated superior T-cell, as well as T-cell subset recovery and a trend towards superior T-cell receptor (TCR) diversity in the first month with this difference persisting through the first year. T-cell repertoire recovery was more rapid and sustained, as well as more diverse in the MMF15 arm.

Conclusion

The long-term superior immune recovery in the MMF15 arm, administered GMCSF, is consistent with a disproportionate impact of early interventions in HCT. Modifying the 'immune-milieu' following allogeneic HCT is feasible and may influence long-term T-cell recovery.

Negative correlation between circulating integrin α4+ group 3 innate lymphoid cells and the severity of type 2 diabetes

BACKGROUND

Impaired intestinal barrier and immune dysfunction promote the development of type 2 diabetes (T2D). Group 3 innate lymphoid cells (ILC3s), which are enriched in the intestinal lamina propria, are key for intestinal barrier integrity. However, there is a paucity of data on circulating ILC3s in patients with T2D.

PURPOSE

To examine the characteristics of ILC3s in patients with T2D and identify the relationship between ILC3s and clinical indicators of T2D.

METHODS

Fifty-nine patients with T2D and thirty controls were enrolled in this retrospective study. Peripheral blood mononuclear cells were isolated and analyzed by flow cytometry and plasma cytokine levels were measured by enzyme-linked immunosorbent assays.

RESULTS

The proportion of circulating ILC3s in the T2D group was significantly lower than that in controls and showed a negative correlation with fasting glucose and glycated hemoglobin and a positive correlation with granulocyte-macrophage colony-stimulating factor (GM-CSF). Similarly, the proportion of circulating integrin α4⁺ ILC3s was also significantly lower in the T2D group and showed a negative correlation with fasting glucose and glycated hemoglobin and a positive correlation with GM-CSF. Moreover, the level of circulating integrin α4⁺ ILC3s showed a positive correlation with the proportion of circulating dendritic cells (DCs), which was also decreased in patients with T2D and positively associated with GM-CSF.

CONCLUSION

ILC3s, especially integrin α4⁺ ILC3s, were decreased in patients with T2D and showed a negative correlation with disease severity. These cell subsets may delay the progression of T2D by promoting DC differentiation via the secretion of GM-CSF.

1,25(OH)2D3 Differently Modulates the Secretory Activity of IFN-DC and IL4-DC: A Study in Cells from Healthy Donors and MS Patients

Immune mechanisms play an essential role in driving multiple sclerosis (MS) and altered trafficking and/or activation of dendritic cells (DC) were observed in the central nervous system and cerebrospinal fluid of MS patients. Interferon β (IFNβ) has been used as a first-line therapy in MS for almost three decades and vitamin D deficiency is a recognized environmental risk factor for MS. Both IFNβ and vitamin D modulate DC functions. Here, we studied the response to 1,25-dihydoxyvitamin D3 (1,25(OH)₂D3) of DC obtained with IFNβ/GM-CSF (IFN-DC) compared to classically derived IL4-DC, in three donor groups: MS patients free of therapy, MS patients undergoing IFNβ therapy, and healthy donors. Except for a decreased CCL2 secretion by IL4-DC from the MS group, no major defects were observed in the 1,25(OH)₂D3 response of either IFN-DC or IL4-DC from MS donors compared to healthy donors. However, the two cell models strongly differed for vitamin D receptor level of expression as well as for basal and 1,25(OH)₂D3-induced cytokine/chemokine secretion. 1,25(OH)₂D3 up-modulated IL6, its soluble receptor sIL6R, and CCL5 in IL4-DC, and down-modulated IL10 in IFN-DC. IFN-DC, but not IL4-DC, constitutively secreted high levels of IL8 and of matrix-metalloproteinase-9, both down-modulated by 1,25(OH)₂D3. DC may contribute to MS pathogenesis, but also provide an avenue for therapeutic intervention. 1,25(OH)₂D3-induced tolerogenic DC are in clinical trial for MS. We show that the protocol of in vitro DC differentiation qualitatively and quantitatively affects secretion of cytokines and chemokines deeply involved in MS pathogenesis.

Targeting GM-CSF in inflammatory and autoimmune disorders

Granulocyte macrophage-colony stimulating factor (GM-CSF) was originally identified as a growth factor for its ability to promote the proliferation and differentiation in vitro of bone marrow progenitor cells into granulocytes and macrophages. Many preclinical studies, using GM-CSF deletion or depletion approaches, have demonstrated that GM-CSF has a wide range of biological functions, including the mediation of inflammation and pain, indicating that it can be a potential target in many inflammatory and autoimmune conditions. This review provides a brief overview of GM-CSF biology and signaling, and summarizes the findings from preclinical models of a range of inflammatory and autoimmune disorders and the latest clinical trials targeting GM-CSF or its receptor in these disorders.

USP19 suppresses inflammation and promotes M2-like macrophage polarization by manipulating NLRP3 function via autophagy

Macrophage polarization to proinflammatory M1-like or anti-inflammatory M2-like cells is critical to mount a host defense or repair tissue. The exact molecular mechanisms controlling this process are still elusive. Here, we report that ubiquitin-specific protease 19 (USP19) acts as an anti-inflammatory switch that inhibits inflammatory responses and promotes M2-like macrophage polarization. USP19 inhibited NLRP3 inflammasome activation by increasing autophagy flux and decreasing the generation of mitochondrial reactive oxygen species. In addition, USP19 inhibited the proteasomal degradation of inflammasome-independent NLRP3 by cleaving its polyubiquitin chains. USP19-stabilized NLRP3 promoted M2-like macrophage polarization by direct association with interferon regulatory factor 4, thereby preventing its p62-mediated selective autophagic degradation. Consistent with these observations, compared to wild-type mice, Usp19^-/- mice had decreased M2-like macrophage polarization and increased interleukin-1β secretion, in response to alum and chitin injections. Thus, we have uncovered an unexpected mechanism by which USP19 switches the proinflammatory function of NLRP3 into an anti-inflammatory function, and suggest that USP19 is a potential therapeutic target for inflammatory interventions.

Antigen-Specific Treatment Modalities in MS: The Past, the Present, and the Future

Antigen-specific therapy for multiple sclerosis may lead to a more effective therapy by induction of tolerance to a wide range of myelin-derived antigens without hampering the normal surveillance and effector function of the immune system. Numerous attempts to restore tolerance toward myelin-derived antigens have been made over the past decades, both in animal models of multiple sclerosis and in clinical trials for multiple sclerosis patients. In this review, we will give an overview of the current approaches for antigen-specific therapy that are in clinical development for multiple sclerosis as well provide an insight into the challenges for future antigen-specific treatment strategies for multiple sclerosis.

GM-CSF: A Promising Target in Inflammation and Autoimmunity

The cytokine, granulocyte macrophage-colony stimulating factor (GM-CSF), was firstly identified as being able to induce in vitro the proliferation and differentiation of bone marrow progenitors into granulocytes and macrophages. Much preclinical data have indicated that GM-CSF has a wide range of functions across different tissues in its action on myeloid cells, and GM-CSF deletion/depletion approaches indicate its potential as an important therapeutic target in several inflammatory and autoimmune disorders, for example, rheumatoid arthritis. In this review, we discuss briefly the biology of GM-CSF, raise some current issues and questions pertaining to this biology, summarize the results from preclinical models of a range of inflammatory and autoimmune disorders and list the latest clinical trials evaluating GM-CSF blockade in such disorders.

GM-CSF in inflammation

GM-CSF is a potential therapeutic target in inflammation and autoimmunity. This study reviews the literature on the biology of GM-CSF, in particular that describing the research leading to clinical trials targeting GM-CSF and its receptor in numerous inflammatory/autoimmune conditions, such as rheumatoid arthritis.

Granulocyte–macrophage colony-stimulating factor (GM-CSF) has many more functions than its original in vitro identification as an inducer of granulocyte and macrophage development from progenitor cells. Key features of GM-CSF biology need to be defined better, such as the responding and producing cell types, its links with other mediators, its prosurvival versus activation/differentiation functions, and when it is relevant in pathology. Significant preclinical data have emerged from GM-CSF deletion/depletion approaches indicating that GM-CSF is a potential target in many inflammatory/autoimmune conditions. Clinical trials targeting GM-CSF or its receptor have shown encouraging efficacy and safety profiles, particularly in rheumatoid arthritis. This review provides an update on the above topics and current issues/questions surrounding GM-CSF biology.

Csf2 Attenuated Sepsis-Induced Acute Kidney Injury by Promoting Alternative Macrophage Transition

Sepsis is a systemic inflammatory state that occurs in response to infection and significantly increases mortality in combination with acute kidney injury (AKI). Macrophages accumulate in the kidney after injury and undergo a transition from a proinflammatory (M1) phenotype to an alternatively activated (M2) phenotype that is required for normal repair. However, the specific signals that regulate the transition from the M1 to M2 phenotype in vivo are unknown. Here, we found an unexpected role of Colony stimulating factor 2 (Csf2) in controlling macrophage transition in vitro and in a mouse model of sepsis induced by cecal ligation and puncture (CLP). We first co-cultured human M1 macrophages with HK-2 cells and characterized cytokine/chemokine profiles via Luminex. Of the cytokines and chemokines that were overexpressed in medium from M1 macrophages cocultured with human kidney-2 (HK-2) cells compared with that from M1 macrophages cultured alone, Csf2 and IL6 showed the greatest increases. Csf2 was exclusively secreted by HK-2 cells but not by M1 macrophages. Furthermore, recombinant human Csf2 protein promoted transition of M1 macrophages to the M2 phenotype in a dose and time-dependent manner. The apoptosis and reactive oxygen species (ROS) release induced by M1 macrophages in HK-2 cells was attenuated after exposure to exogenous Csf2. In addition, the switch from the proinflammatory M1 phenotype to the M2 phenotype occurred via the p-Stat5 pathway, which was activated by Csf2. Importantly, we found that intraperitoneal injection of a Csf2-neutralizing antibody after CLP aggravated kidney injury and suppressed tubular proliferation, subsequently decreasing survival. However, administration of recombinant mouse Csf2 protein could rescue mice with sepsis. Together, our results indicate that Csf2 plays critical roles in regulating macrophage transition via activation of p-STAT5. These data form a foundation upon which new therapeutic strategies can be designed to improve the therapeutic efficacy of cytokine-based treatments for sepsis-induced AKI.

Evaluation of soluble expression of recombinant granulocyte macrophage stimulating factor (rGM-CSF) by three different E. coli strains

Background and purpose:

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine with a wide range of therapeutic applications although expression of GM-CSF in Escherichia coli (E. coli) usually leads to formation of insoluble aggregates mostly lack biological activity. The aim of this study was to compare the soluble expression level of GM-CSF in three E. coli strains, BL21 (DE3), SHuffle® T7 and Origami™ 2 (DE3).

Experimental approach:

The effect of different temperatures and inducer concentrations on soluble expression of GM-CSF was evaluated. The soluble GM-CSF was subjected to endotoxin removal and purification using nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography, ultrafiltration. The biological activity of produced GM-CSF was evaluated based on its growth promotion effect on TF-1 cell lines by MTT assay method.

Findings / Results:

A significant improvement of the soluble yield of GM-CSF (about 30% of GM-CSF was expressed as soluble proteins) was observed when protein expression was induced at 30 °C with 0.5 mM isopropyl β- d-1-thiogalactopyranoside (IPTG) in E. coli Shuffle T7. The soluble GM-CSF with a high purity up to 95 % and specific activity of 1.25 × 10⁴ IU/μg was obtained.

Conclusion and implications:

The proposed strategy here can be used to improve the soluble expression of other hard-to-express proteins with similar structural properties (i.e., containing disulfide binds or cysteine).

Intratumoral Immunotherapy-Update 2019

Intratumoral immunotherapies aim to trigger local and systemic immunologic responses via direct injection of immunostimulatory agents with the goal of tumor cell lysis, followed by release of tumor‐derived antigens and subsequent activation of tumor‐specific effector T cells. In 2019, a multitude of intratumoral immunotherapies with varied mechanisms of action, including nononcolytic viral therapies such as PV‐10 and toll‐like receptor 9 agonists and oncolytic viral therapies such as CAVATAK, Pexa‐Vec, and HF10, have been extensively evaluated in clinical trials and demonstrated promising antitumor activity with tolerable toxicities in melanoma and other solid tumor types. Talimogene laherparepvec (T‐VEC), a genetically modified herpes simplex virus type 1–based oncolytic immunotherapy, is the first oncolytic virus approved by the U.S. Food and Drug Administration for the treatment of unresectable melanoma recurrent after initial surgery. In patients with unresectable metastatic melanoma, T‐VEC demonstrated a superior durable response rate (continuous complete response or partial response lasting ≥6 months) over subcutaneous GM‐CSF (16.3% vs. 2.1%; p < .001). Responses were seen in both injected and uninjected lesions including visceral lesions, suggesting a systemic antitumor response. When combined with immune checkpoint inhibitors, T‐VEC significantly improved response rates compared with single agent; similar results were seen with combinations of checkpoint inhibitors and other intratumoral therapies such as CAVATAK, HF10, and TLR9 agonists. In this review, we highlight recent results from clinical trials of key intratumoral immunotherapies that are being evaluated in the clinic, with a focus on T‐VEC in the treatment of advanced melanoma as a model for future solid tumor indications.

Implications for Practice

This review provides oncologists with the latest information on the development of key intratumoral immunotherapies, particularly oncolytic viruses. Currently, T‐VEC is the only U.S. Food and Drug Administration (FDA)‐approved oncolytic immunotherapy. This article highlights the efficacy and safety data from clinical trials of T‐VEC both as monotherapy and in combination with immune checkpoint inhibitors. This review summarizes current knowledge on intratumoral therapies, a novel modality with increased utility in cancer treatment, and T‐VEC, the only U.S. FDA‐approved oncolytic viral therapy, for medical oncologists. This review evaluates approaches to incorporate T‐VEC into daily practice to offer the possibility of response in selected melanoma patients with manageable adverse events as compared with other available immunotherapies.

This review highlights recent results from clinical trials of key intratumoral immunotherapies that are being evaluated in the clinic, with a focus on talimogene laherparepvec in the treatment of advanced melanoma as a model for future solid tumor indications.

GM-CSF-Dependent Inflammatory Pathways

Pre-clinical models and clinical trials demonstrate that targeting the action of the cytokine, granulocyte macrophage-colony stimulating factor (GM-CSF), can be efficacious in inflammation/autoimmunity reinforcing the importance of understanding how GM-CSF functions; a significant GM-CSF-responding cell in this context is likely to be the monocyte. This article summarizes critically the literature on the downstream cellular pathways regulating GM-CSF interaction with monocytes (and macrophages), highlighting some contentious issues, and conclusions surrounding this biology. It also suggests future directions which could be undertaken so as to more fully understand this aspect of GM-CSF biology. Given the focus of this collection of articles on monocytes, the following discussion in general will be limited to this population or to its more mature progeny, the macrophage, even though GM-CSF biology is broader than this.

Tofacitinib inhibits granulocyte-macrophage colony-stimulating factor-induced NLRP3 inflammasome activation in human neutrophils

Background

Granulocyte–macrophage colony-stimulating factor (GM-CSF) has emerged as a crucial cytokine that activates myeloid cells to initiate tissue inflammation. However, the molecular actions of GM-CSF against innate immunity are still poorly characterized. Here, we investigated the in vitro effects of GM-CSF on the activation of human myeloid lineages, neutrophils, and the underlying intracellular signaling mechanism, including inflammasome activation.

Methods

Human neutrophils were stimulated with GM-CSF in the presence or absence of tofacitinib. The cellular supernatants were analyzed for interleukin-1 beta (IL-1β) and caspase-1 by enzyme-linked immunosorbent assay (ELISA) methods. Pro-IL-1β mRNA expressions in human neutrophils were analyzed by real-time polymerase chain reaction. Protein phosphorylation of neutrophils was assessed by Western blot using phospho-specific antibodies.

Results

Stimulation with GM-CSF alone, but not tumor necrosis factor-alpha, was shown to increase the release of IL-1β and cleaved caspase-1 (p20) from human neutrophils. Tofacitinib, which inhibits GM-CSF–induced Janus kinase 2 (Jak2)-mediated signal transduction, completely abrogated GM-CSF–induced IL-1β and caspase-1 (p20) secretion from neutrophils. GM-CSF stimulation also induced pro-IL-1β mRNA expression in neutrophils and induced NLR family pyrin domain-containing 3 (NLRP3) protein expression. Although tofacitinib pretreatment marginally inhibited GM-CSF–induced pro-IL-1β mRNA expression, tofacitinib completely abrogated NLRP3 protein expression in neutrophils.

Conclusions

These results indicate that GM-CSF signaling induces NLRP3 expression and subsequent IL-1β production by affecting neutrophils, which may cause the activation of innate immunity. Therefore, GM-CSF is a key regulator of the NLRP3 inflammasome and IL-1β production by activating innate immune cells. This process can be blocked by tofacitinib, which interferes with JAK/STAT signaling pathways.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1685-x) contains supplementary material, which is available to authorized users.

Stable incorporation of GM-CSF into dissolvable microneedle patch improves skin vaccination against influenza

The widely used influenza subunit vaccine would benefit from increased protection rates in vulnerable populations. Skin immunization by microneedle (MN) patch can increase vaccine immunogenicity, as well as increase vaccination coverage due to simplified administration. To further increase immunogenicity, we used granulocyte-macrophage colony stimulating factor (GM-CSF), an immunomodulatory cytokine already approved for skin cancer therapy and cancer support treatment. GM-CSF has been shown to be upregulated in skin following MN insertion. The GM-CSF-adjuvanted vaccine induced robust and long-lived antibody responses cross-reactive to homosubtypic and heterosubtypic influenza viruses. Addition of GM-CSF resulted in increased memory B cell persistence relative to groups given influenza vaccine alone and led to rapid lung viral clearance following lethal infection with homologous virus in the mouse model. Here we demonstrate that successful incorporation of the thermolabile cytokine GM-CSF into MN resulted in improved vaccine-induced protective immunity holding promise as a novel approach to improved influenza vaccination. To our knowledge, this is the first successful incorporation of a cytokine adjuvant into dissolvable MNs, thus advancing and diversifying the rapidly developing field of MN vaccination technology.

Docetaxel promotes the generation of anti-tumorigenic human macrophages

The taxanes Docetaxel and Paclitaxel are two of the standard chemotherapies for patients with metastatic breast cancer. The functional effect of Docetaxel and Paclitaxel on human innate immune cells of the myeloid lineage is not well established, nor is the effects these agents have on differentiation of monocytes into macrophages and dendritic cells. Therefore, the aim with this project was to determine the effects of Docetaxel and Paclitaxel on primary human monocyte differentiation, activation and function. For this purpose, primary human monocytes were isolated from healthy donors and cultured with or without Docetaxel and Paclitaxel. We found that Docetaxel promoted the differentiation of primary human monocytes into pro-inflammatory macrophages with an M1 phenotype and an ability to present antigens to T cells. Monocytes treated with Docetaxel also displayed an elevated secretion of IL-8 and IL-1β, but did not promote generation of monocytic myeloid-derived suppressor cells. In conclusion, Docetaxel appears to have an immune stimulatory effect that would be beneficial for an anti-tumorigenic type of immune response, whereas Paclitaxel seems to have less effect on myeloid cells.

Future therapeutic targets in rheumatoid arthritis?

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by persistent joint inflammation. Without adequate treatment, patients with RA will develop joint deformity and progressive functional impairment. With the implementation of treat-to-target strategies and availability of biologic therapies, the outcomes for patients with RA have significantly improved. However, the unmet need in the treatment of RA remains high as some patients do not respond sufficiently to the currently available agents, remission is not always achieved and refractory disease is not uncommon. With better understanding of the pathophysiology of RA, new therapeutic approaches are emerging. Apart from more selective Janus kinase inhibition, there is a great interest in the granulocyte macrophage-colony stimulating factor pathway, Bruton's tyrosine kinase pathway, phosphoinositide-3-kinase pathway, neural stimulation and dendritic cell-based therapeutics. In this review, we will discuss the therapeutic potential of these novel approaches.

Microarray analysis of the genes associated with osteitis in chronic rhinosinusitis

OBJECTIVES/HYPOTHESIS

Although numerous studies have examined epithelial remodeling in chronic rhinosinusitis (CRS), bone remodeling (osteitis) has only recently gained attention as a potential significant contributor to the pathophysiology of recalcitrant CRS. The purpose of this study was to compare gene expression profiles between osteitic bone and the adjacent diseased mucosa in patients with CRS to determine which genes affect mucosal and bony remodeling.

STUDY DESIGN

Prospective experimental analysis.

METHODS

Samples were obtained from sites of osteitic bone and overlying mucosa in CRS patients demonstrating osteitis on computed tomography and compared to healthy controls. The entire transcripted gene expression profile was determined by microarray following RNA isolation and compared between tissue samples. The expression differences were verified by reverse transcriptase-polymerase chain reaction and immunohistochemical staining.

RESULTS

Growth differentiation factor 5 and exostosin glycosyltransferase 1 were significantly upregulated and positively correlated with mucosal eosinophilic inflammation in osteitic bone. Fibroblast growth factor was significantly increased in osteitic bone. Additionally, colony stimulating factor was positively correlated with the degree of osteitis.

CONCLUSIONS

These findings will add a new perspective to our current understanding of the recalcitrant CRS.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:E85-E90, 2017.

Talimogene Laherparepvec in Combination With Ipilimumab in Previously Untreated, Unresectable Stage IIIB-IV Melanoma

PURPOSE

Combining immunotherapeutic agents with different mechanisms of action may enhance efficacy. We describe the safety and efficacy of talimogene laherparepvec (T-VEC; an oncolytic virus) in combination with ipilimumab (a cytotoxic T-lymphocyte-associated antigen 4 checkpoint inhibitor) in patients with advanced melanoma.

METHODS

In this open-label, multicenter, phase Ib trial of T-VEC in combination with ipilimumab, T-VEC was administered intratumorally in week 1 (10(6) plaque-forming units/mL), then in week 4 and every 2 weeks thereafter (10(8) plaque-forming units/mL). Ipilimumab (3 mg/kg) was administered intravenously every 3 weeks for four infusions, beginning in week 6. The primary end point was incidence of dose-limiting toxicities. Secondary end points were objective response rate by immune-related response criteria and safety.

RESULTS

Median duration of treatment with T-VEC was 13.3 weeks (range, 2.0 to 95.4 weeks). Median follow-up time for survival analysis was 20.0 months (1.0 to 25.4 months). Nineteen patients were included in the safety analysis. No dose-limiting toxicities occurred, and no new safety signals were detected. Grade 3/4 treatment-related adverse events (AEs) were seen in 26.3% of patients; 15.8% had AEs attributed to T-VEC, and 21.1% had AEs attributed to ipilimumab. The objective response rate was 50%, and 44% of patients had a durable response lasting ≥ 6 months. Eighteen-month progression-free survival was 50%; 18-month overall survival was 67%.

CONCLUSION

T-VEC with ipilimumab had a tolerable safety profile, and the combination appeared to have greater efficacy than either T-VEC or ipilimumab monotherapy.

Gallic Acid Is the Major Active Component of Cortex Moutan in Inhibiting Immune Maturation of Human Monocyte-Derived Dendritic Cells

Atopic dermatitis (AD) is a widely prevalent and chronically relapsing inflammatory skin disease. Penta Herbs Formula (PHF) is efficacious in improving the quality of life and reducing topical corticosteroid used in children with AD and one of the active herbs it contains is Cortex Moutan. Recent studies showed that altered functions of dendritic cells (DC) were observed in atopic individuals, suggesting that DC might play a major role in the generation and maintenance of inflammation by their production of pro-inflammatory cytokines. Hence, the aims of the present study were to identify the major active component(s) of Cortex Moutan, which might inhibit DC functions and to investigate their possible interactions with conventional corticosteroid on inhibiting the development of DC from monocytes. Monocyte-derived dendritic cells (moDC) culture model coupled with the high-speed counter-current chromatography (HSCCC), high pressure liquid chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LCMS) analyses were used. Gallic acid was the major active component from Cortex Moutan which could dose dependently inhibit interleukin (IL)-12 p40 and the functional cluster of differentiation (CD) surface markers CD40, CD80, CD83 and CD86 expression from cytokine cocktail-activated moDC. Gallic acid could also lower the concentration of hydrocortisone required to inhibit the activation of DC.

Overcoming HBV immune tolerance to eliminate HBsAg-positive hepatocytes via pre-administration of GM-CSF as a novel adjuvant for a hepatitis B vaccine in HBV transgenic mice

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is known to be a potential vaccine adjuvant despite contradictory results from animal and human studies. The discrepancies may be due to the different doses and regimens of GM-CSF that were used, given that either mature or immature dendritic cells (DCs) could be induced under different conditions. To test the hypothesis that GM-CSF can be used as a novel adjuvant for a hepatitis B virus (HBV) therapeutic vaccine, we administered GM-CSF once per day for three days prior to vaccination with recombinant HBV vaccine (rHBVvac) in mice. We observed greater DC maturation in these pre-treated animals at day 3 as compared to day 1 or day 2 of daily GM-CSF administration. This strategy was further investigated for its ability to break the immune tolerance established in hepatitis B surface antigen-transgenic (HBsAg-Tg) animals. We found that the levels of induced anti-HBsAg antibodies were significantly higher in animals following three days of GM-CSF pre-treatment before rHBV vaccination after the third immunization. In addition to the increase in anti-HBsAg antibody levels, cell-mediated anti-HBsAg responses, including delayed-type hypersensitivity, T-cell proliferation, interferon-γ production, and cytotoxic T lymphocytes, were dramatically enhanced in the three-day GM-CSF pre-treated group. After adoptive transfers of CD8⁺ T cells from immunized animals, antigen-specific CD8⁺ T cells were observed in the livers of recipient HBsAg-Tg animals. Moreover, the three-day pre-treatments with GM-CSF prior to rHBVvac vaccination could significantly eliminate HBsAg-positive hepatocytes, suggesting beneficial therapeutic effects. Therefore, this protocol utilizing GM-CSF as an adjuvant in combination with the rHBVvac vaccine has the potential to become a novel immunotherapy for chronic hepatitis B patients.

GM-CSF: An immune modulatory cytokine that can suppress autoimmunity

GM-CSF was originally identified as a colony stimulating factor (CSF) because of its ability to induce granulocyte and macrophage populations from precursor cells. Multiple studies have demonstrated that GM-CSF is also an immune-modulatory cytokine, capable of affecting not only the phenotype of myeloid lineage cells, but also T-cell activation through various myeloid intermediaries. This property has been implicated in the sustenance of several autoimmune diseases like arthritis and multiple sclerosis. In contrast, several studies using animal models have shown that GM-CSF is also capable of suppressing many autoimmune diseases such as Crohn's disease, Type-1 diabetes, Myasthenia gravis and experimental autoimmune thyroiditis. Knockout mouse studies have suggested that the role of GM-CSF in maintaining granulocyte and macrophage populations in the physiological steady state is largely redundant. Instead, its immune-modulatory role plays a significant role in the development or resolution of autoimmune diseases. This is mediated either through the differentiation of precursor cells into specialized non-steady state granulocytes, macrophages and dendritic cells, or through the modulation of the phenotype of mature myeloid cells. Thus, outside of myelopoiesis, GM-CSF has a profound role in regulating the immune response and maintaining immunological tolerance.

Protomyofibroblast Pathway in Early Thermal Burn Healing

Wound healing following partial thickness thermal burns is commonly hampered by the risk of hypertrophic scarring. Skin myofibroblast (MF) density is commonly increased in postburn healing. The transition between fibroblast-like cells and α-smooth muscle actin (SMA)+ MF possibly begins with CD14+ monocytes, evolving to CD14+ CD34+ fibrocytes, followed by β-SMA+ protomyofibroblast (PMF) maturation. Skin biopsies from 25 burn patients were collected about 1 and 4 weeks after injury. Immunohistochemistry was performed using monoclonal antibodies to α-SMA, β-SMA, factor XIIIa, lysozyme, Mac 387, CD14, CD117 and Ulex europaeus agglutinin-1 (UEA-1). The set of Mac 387+ and CD14+ monocytes was accompanied by both CD34+ fibrocytes and factor XIIIa+ dendrocytes. By contrast, β-SMA+ PMF were rare. Of note, α-SMA+ MF were more abundant at week 4 than at week 1 (p < 0.01). The UEA-1+ endothelial cells showed marked variations in their dermal distribution, irrespective of the densities in the other scrutinized cells. In conclusion, healing of partial thickness thermal burns involves a diversity of cell types including PMF. In the present samples, the PMF density remained low. © 2015 S. Karger AG, Basel.

The cysteine-rich core domain of REIC/Dkk-3 is critical for its effect on monocyte differentiation and tumor regression

Reduced expression in immortalized cells (REIC)/Dickkopf (Dkk)-3 is a tumor-suppressor gene and has been studied as a promising therapeutic gene for cancer gene therapy. Intratumoral injection of an adenovirus vector carrying the human REIC/Dkk-3 gene (Ad-REIC) elicits cancer cell-specific apoptosis and anticancer immune responses. The cytokine-like effect of secretory REIC/Dkk-3 on the induction of dendritic cell (DC)-like cell differentiation from monocytes plays a role in systemic anticancer immunity. In the present study, we generated recombinant full-length and N-terminally truncated REIC/Dkk-3 to characterize the biological activity of the protein. During the purification procedure, we identified a 17 kDa cysteine-rich stable product (C17-REIC) showing limited degradation. Further analysis showed that the C17-REIC domain was sufficient for the induction of DC-like cell differentiation from monocytes. Concomitant with the differentiation of DCs, the REIC/Dkk-3 protein induced the phosphorylation of glycogen synthase kinase 3β (GSK-3β) and signal transducers and activators of transcription (STAT) at a level comparable to that of granulocyte/macrophage colony-stimulating factor. In a mouse model of subcutaneous renal adenocarcinoma, intraperitoneal injection of full-length and C17-REIC proteins exerted anticancer effects in parallel with the activation of immunocompetent cells such as DCs and cytotoxic T lymphocytes in peripheral blood. Taken together, our results indicate that the stable cysteine-rich core region of REIC/Dkk-3 is responsible for the induction of anticancer immune responses. Because REIC/Dkk-3 is a naturally circulating serum protein, the upregulation REIC/Dkk-3 protein expression could be a promising option for cancer therapy.

The fungal quorum-sensing molecule farnesol activates innate immune cells but suppresses cellular adaptive immunity

Farnesol, produced by the polymorphic fungus Candida albicans, is the first quorum-sensing molecule discovered in eukaryotes. Its main function is control of C. albicans filamentation, a process closely linked to pathogenesis. In this study, we analyzed the effects of farnesol on innate immune cells known to be important for fungal clearance and protective immunity. Farnesol enhanced the expression of activation markers on monocytes (CD86 and HLA-DR) and neutrophils (CD66b and CD11b) and promoted oxidative burst and the release of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α] and macrophage inflammatory protein 1 alpha [MIP-1α]). However, this activation did not result in enhanced fungal uptake or killing. Furthermore, the differentiation of monocytes to immature dendritic cells (iDC) was significantly affected by farnesol. Several markers important for maturation and antigen presentation like CD1a, CD83, CD86, and CD80 were significantly reduced in the presence of farnesol. Furthermore, farnesol modulated migrational behavior and cytokine release and impaired the ability of DC to induce T cell proliferation. Of major importance was the absence of interleukin 12 (IL-12) induction in iDC generated in the presence of farnesol. Transcriptome analyses revealed a farnesol-induced shift in effector molecule expression and a down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor during monocytes to iDC differentiation. Taken together, our data unveil the ability of farnesol to act as a virulence factor of C. albicans by influencing innate immune cells to promote inflammation and mitigating the Th1 response, which is essential for fungal clearance.

Farnesol is a quorum-sensing molecule which controls morphological plasticity of the pathogenic yeast Candida albicans. As such, it is a major mediator of intraspecies communication. Here, we investigated the impact of farnesol on human innate immune cells known to be important for fungal clearance and protective immunity. We show that farnesol is able to enhance inflammation by inducing activation of neutrophils and monocytes. At the same time, farnesol impairs differentiation of monocytes into immature dendritic cells (iDC) by modulating surface phenotype, cytokine release and migrational behavior. Consequently, iDC generated in the presence of farnesol are unable to induce proper T cell responses and fail to secrete Th1 promoting interleukin 12 (IL-12). As farnesol induced down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor, desensitization to GM-CSF could potentially explain transcriptional reprofiling of iDC effector molecules. Taken together, our data show that farnesol can also mediate Candida-host communication and is able to act as a virulence factor.

Dendritic cells enhance the activity of human MUC1-stimulated mononuclear cells against breast cancer

Dendritic cells (DCs) are among the most potent antigen-presenting cells (APCs), stimulating peripheral blood mononuclear cells (PBMCs) to generate antigen-specific cytotoxic T lymphocytes (CTLs). The objectives of this study were to determine if interleukin (IL)-4 is beneficial or detrimental for the generation of human DCs in vitro and to understand whether DCs generated in vitro in the presence or absence of IL-4 stimulate the killing of adenocarcinoma cells by CTLs in vivo. Mucin 1 (MUC1), a glycoprotein found on the surface of adenocarcinoma cells was used to load DCs. MUC1-loaded DCs generated in the absence of IL-4 were superior to their counterparts produced with IL-4 in stimulating PBMCs to kill human breast cancer MCF-7 cells in vitro. A corollary in vivo protection experiment was performed by injecting immunodeficient NOD-SCID mice with MCF-7 cells s.c. and MUC1-loaded CTLs, PBMCs, or DCs generated in the absence of IL-4, i.p. Mice that received CTLs and MUC1-loaded DCs on days 0, 2, 4, 9, 14 and 19 were completely protected against the development of MCF-7-derived tumors, while other schedules conferred lower protection. Therefore, tumor antigen-loaded DCs enhance the efficacy of adoptive CTL transfer, and should thus be considered for combinatorial immunotherapeutic regimens.

The plasticity of inflammatory monocyte responses to the inflamed central nervous system

Over the last three decades it has become increasingly clear that monocytes, originally thought to have fixed, stereotypic responses to foreign stimuli, mediate exquisitely balanced protective and pathogenic roles in disease and immunity. This balance is crucial in core functional organs, such as the central nervous system (CNS), where minor changes in neuronal microenvironments and the production of immune factors can result in significant disease with fatal consequences or permanent neurological sequelae. Viral encephalitis and multiple sclerosis are examples of important human diseases in which the pathogenic contribution of monocytes recruited from the bone marrow plays a critical role in the clinical expression of disease, as they differentiate into macrophage or dendritic cells in the CNS to carry out effector functions. While antigen-specific lymphocyte populations are central to the adaptive immune response in both cases, in viral encephalitis a prominent macrophage infiltration may mediate immunopathological damage, seizure induction, and death. However, the autoimmune response to non-replicating, non-infectious, but abundant, self antigen has a different disease progression, associated with differentiation of significant numbers of infiltrating monocytes into dendritic cells in the CNS. Whilst a predominant presence of macrophages or dendritic cells in the inflamed CNS in viral encephalitis or multiple sclerosis is well described, the way in which the inflamed CNS mobilizes monocytes in the bone marrow to migrate to the CNS and the key drivers that lead to these specific differentiation pathways in vivo are not well understood. Here we review the current understanding of factors facilitating inflammatory monocyte generation, migration and entry into the brain, as well as their differentiation towards macrophages or dendritic cells in viral and autoimmune disease in relation to their respective disease outcomes.

Type I interferons as regulators of human antigen presenting cell functions

Type I interferons (IFNs) are pleiotropic cytokines, initially described for their antiviral activity. These cytokines exhibit a long record of clinical use in patients with some types of cancer, viral infections and chronic inflammatory diseases. It is now well established that IFN action mostly relies on their ability to modulate host innate and adaptive immune responses. Work in recent years has begun to elucidate the mechanisms by which type I IFNs modify the immune response, and this is now recognized to be due to effects on multiple cell types, including monocytes, dendritic cells (DCs), NK cells, T and B lymphocytes. An ensemble of results from both animal models and in vitro studies emphasized the key role of type I IFNs in the development and function of DCs, suggesting the existence of a natural alliance between these cytokines and DCs in linking innate to adaptive immunity. The identification of IFN signatures in DCs and their dysregulation under pathological conditions will therefore be pivotal to decipher the complexity of this DC-IFN interaction and to better exploit the therapeutic potential of these cells.

Immunomodulatory activities of Ganoderma sinense polysaccharides in human immune cells

Medicinal mushrooms have been traditionally used as food nutrient supplements in China for thousands of years. The present study aimed to evaluate the immunomodulatory activities of Ganoderma sinense (GS), an allied species of G. lucidum, using human peripheral blood mononuclear cells (PBMC). Our results showed that the polysaccharide-enriched fraction of GS hot water extract (400 μg/ml) exhibited significant stimulatory effects on PBMC proliferation. When the fruiting bodies of GS were divided into pileus and stipe parts and were separately extracted, the GS stipe polysaccharide-enriched fraction (50-400 μg/ml) showed concentration-dependent immunostimulating effects in PBMC. The productions of tumor necrosis factor-α, interleukin (IL)-10, and transforming growth factor -β were significantly enhanced by this fraction. In addition, the proportion of CD14(+) monocyte subpopulation within the PBMC was specifically increased. The IL-10 and IL-12 productions in monocyte-derived dendritic cells were significantly enhanced by GS stipe fraction. The composition of monosaccharides of this fraction was determined by ultra performance liquid chromatography and ion exchange chromatography. Our study demonstrated for the first time the immunostimulatory effects of GS stipe polysaccharide-enriched fraction on PBMC and dendritic cells. The findings revealed the potential use of GS (especially including the stipes of fruiting bodies) as adjuvant nutrient supplements for patients, who are receiving immunosuppressive chemotherapies.

piggyBac transposon plus insulators overcome epigenetic silencing to provide for stable signaling pathway reporter cell lines

Genetically modified hematopoietic progenitors represent an important testing platform for a variety of cell-based therapies, pharmaceuticals, diagnostics and other applications. Stable expression of a transfected gene of interest in the cells is often obstructed by its silencing. DNA transposons offer an attractive non-viral alternative of transgene integration into the host genome, but their broad applicability to leukocytes and other "transgene unfriendly" cells has not been fully demonstrated. Here we assess stability of piggyBac transposon-based reporter expression in murine prostate adenocarcinoma TRAMP-C2, human monocyte THP-1 and erythroleukemia K562 cell lines, along with macrophages and dendritic cells (DCs) that have differentiated from the THP-1 transfects. The most efficient and stable reporter activity was observed for combinations of the transposon inverted terminal repeats and one 5'- or two cHS4 core insulators flanking a green fluorescent protein reporter construct, with no detectable silencing over 10 months of continuous cell culture in absence of any selective pressure. In monocytic THP-1 cells, the functional activity of luciferase reporters for NF-κB, Nrf2, or HIF-1α has not decreased over time and was retained following differentiation into macrophages and DCs, as well. These results imply pB as a versatile tool for gene integration in monocytic cells in general, and as a convenient access route to DC-based signaling pathway reporters suitable for high-throughput assays, in particular.

A suppressor of cytokine signaling 1 antagonist enhances antigen-presenting capacity and tumor cell antigen-specific cytotoxic T lymphocyte responses by human monocyte-derived dendritic cells

The suppressor of cytokine signaling 1 (SOCS1) has emerged as a critical inhibitory molecule for controlling the cytokine response and antigen presentation by dendritic cells (DCs), thereby regulating the magnitude of both innate and adaptive immunity. The aim of this study was to investigate whether the SOCS1 antagonist pJAK2(1001-1013) peptide can weaken or block the inhibition function of SOCS1 in DCs by evaluating the phenotype and cytokine production, antigen-presenting, and specific T-cell-activating capacities of DCs electroporated with human gastric cancer cell total RNA. Furthermore, STAT1 activation of the JAK/STAT signal pathway mediated by SOCS1 was analyzed by Western blotting. The results demonstrate that the SOCS1 antagonist pJAK2(1001-1013) peptide upregulated the expression of the maturation marker (CD83) and costimulatory molecule (CD86) of RNA-electroporated human monocyte-derived mature DCs (mDCs), potentiated the capacity of mDCs to induce T-cell proliferation, stimulated the secretion of proinflammatory cytokines, and enhanced the cytotoxicity of tumor cell antigen-specific CTLs activated by human gastric cancer cell total RNA-electroporated mDCs. Data from Western blot analysis indicate that STAT1 was further activated in pJAK2(1001-1013) peptide-loaded mDCs. These results imply that the SOCS1 antagonist pJAK2(1001-1013) peptide is an effective reagent for the enhancement of antigen-specific antitumor immunity by DCs.

GM-CSF alters dendritic cells in autoimmune diseases

Autoimmune diseases arise from an inappropriate immune response against self components, including macromolecules, cells, tissues, organs etc. They are often triggered or accompanied by inflammation, during which the levels of granulocyte macrophage colony-stimulating factor (GM-CSF) are elevated. GM-CSF is an inflammatory cytokine that has profound impact on the differentiation of immune system cells of myeloid lineage, especially dendritic cells (DCs) that play critical roles in immune initiation and tolerance, and is involved in the pathogenesis of autoimmune diseases. Although GM-CSF was discovered decades ago, recent studies with some new findings have shed an interesting light on the old hematopoietic growth factor. In the inflammatory autoimmune diseases, GM-CSF redirects the normal developmental pathway of DCs, conditions their antigen presentation capacities and endows them with unique cytokine signatures to affect autoimmune responses. Here we review the latest advances in the field, with the aim of demonstrating the effects of GM-CSF on DCs and their influences on autoimmune diseases. The summarized knowledge will help to design DC-based strategies for the treatment of autoimmune diseases.

Molecular cloning, recombinant expression and characterization of GMCSF from the rhesus monkey, Macaca mulatta

Recent studies have found that, in addition to hematopoiesis, granulocyte-macrophage colony-stimulating factor (GMCSF) plays pivotal roles in multiple immune disorders. The gene encoding Macaca mulatta GMCSF (mmGMCSF) was cloned from stimulated peripheral blood mononuclear cells (PBMCs). Concanavalin A (Con A) and mismatched allogeneic antigen-stimulation significantly increased the production of mmGMCSF by monkey PBMCs. The gene encoding mature mmGMCSF was first expressed as a soluble fusion protein in Escherichia coli, and native mmGMCSF was further prepared by protease cleavage. The recombinant mmGMCSF induced antigen-presenting dendritic cells from monkey PBMCs, suggesting a central role of mmGMCSF in the immune system of the rhesus monkey. Although the predicted mature mmGMCSF protein differs from human GMCSF (hGMCSF) at six amino acid residues, mmGMCSF showed a strong ability to support human TF-1 cell survival. Additional co-immunoprecipitation experiments revealed that mmGMCSF cross reacts with the hGMCSF receptor (hGMCSFR). In addition, the hGMCSF-neutralizing agents hGMCSFR-Fc and anti-hGMCSF antibody reduced the biological effects of mmGMCSF on TF-1 cells. These results suggest that recombinant mmGMCSF might be used for the in vitro evaluation of novel hGMCSF-neutralizing agents prior to the in vivo preclinical evaluation of these agents in the rhesus monkey model.

β-Glucan derived from Aureobasidium pullulans is effective for the prevention of influenza in mice

β-(1→3)-D-glucans with β-(1→6)-glycosidic linked branches produced by mushrooms, yeast and fungi are known to be an immune activation agent, and are used in anti-cancer drugs or health-promoting foods. In this report, we demonstrate that oral administration of Aureobasidium pullulans-cultured fluid (AP-CF) enriched with the β-(1→3),(1→6)-D-glucan exhibits efficacy to protect mice infected with a lethal titer of the A/Puerto Rico/8/34 (PR8; H1N1) strain of influenza virus. The survival rate of the mice significantly increased by AP-CF administration after sublethal infection of PR8 virus. The virus titer in the mouse lung homogenates was significantly decreased by AP-CF administration. No significant difference in the mRNA expression of inflammatory cytokines, and in the population of lymphocytes was observed in the lungs of mice administered with AP-CF. Interestingly, expression level for the mRNA of virus sensors, RIG-I (retinoic acid-inducible gene-I) and MDA5 (melanoma differentiation-associated protein 5) strongly increased at 5 hours after the stimulation of A. pullulans-produced purified β-(1→3),(1→6)-D-glucan (AP-BG) in murine macrophage-derived RAW264.7 cells. Furthermore, the replication of PR8 virus was significantly repressed by pre-treatment of AP-BG. These findings suggest the increased expression of virus sensors is effective for the prevention of influenza by the inhibition of viral replication with the administration of AP-CF.

Generation of immunogenic and tolerogenic clinical-grade dendritic cells

Immunotherapy with dendritic cells (DCs), which have been manipulated ex vivo to become immunogenic or tolerogenic, has been tested in clinical trials for disease therapy. DCs are sentinels of the immune system, which after exposure to antigenic or inflammatory signals and crosstalk with effector CD4(+) T cells express high levels of costimulatory molecules and cytokines. Upregulation of either costimulatory molecules or cytokines promotes immunologic DCs, whereas their downregulation generates tolerogenic DCs (TDCs), which induce T regulatory cells (Tregs) and a state of tolerance. Immunogenic DCs are used for the therapy of infectious diseases such as HIV-1 and cancer, whereas tolerogenic DCs are used in treating various autoimmune diseases and in transplantation. DC vaccination is still at an early stage, and improvements are mainly needed in quality control of monitoring assays to generate clinical-grade DC products and to assess the effect of DC vaccination in future clinical trials. Here, we review the recent work in DC generation and monitoring approaches for DC-based trials with immunogenic or tolerogenic DCs.

Monocyte-derived interferon-alpha primed dendritic cells in the pathogenesis of psoriasis: new pieces in the puzzle

Psoriasis is a common chronic inflammatory skin disorder with serious clinical, psychosocial, and economic consequences. There is much evidence that different dendritic cell (DC) subsets, various proinflammatory cytokines and Toll-like receptors (TLRs) have a central role in the pathogenesis of the disease. One of the early events in psoriatic inflammation is the secretion of interferon (IFN)-α by activated plasmacytoid DCs, a special DC subset present in symptomless psoriatic skin. Secreted IFN-α along with other proinflammatory cytokines can lead to monocyte-derived DC (moDC) development, which might contribute to T-helper (Th)1 and Th17 lymphocyte differentiation/activation and to keratinocyte proliferation. Recently it was proven that interleukin (IL)-12 and IL-23 play a critical role in this process. Additionally in psoriatic lesions, Th1 and Th17 lympocytes can interact with monocytes and instruct these cells to differentiate into Th1- and Th17-promoting moDCs, further governing the formation and function of specialized moDC subsets. The concept we present here focuses on the initial and central role of IFN-α, on the importance of other proinflammatory cytokines, on TLR stimulation and on the effect of T lymphocytes in priming moDCs, which may play an important role in initiating and maintaining psoriasis.

Increased levels of serum granulocyte-macrophage colony-stimulating factor is associated with activated peripheral dendritic cells in type 2 diabetes subjects (CURES-99)

BACKGROUND

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pro-inflammatory cytokine with growth factor-like properties for monocytes and dendritic cells (DCs). In the present study, serum GM-CSF levels and the activation status of DCs were studied in type 2 diabetes mellitus (T2DM) subjects.

METHODS

Study subjects were recruited from the Chennai Urban Rural Epidemiology Study. Healthy controls (n=45) and T2DM patients (n=45) were included in the study. Serum levels of GM-CSF, interleukin-1β, interleukin-6, and tumor necrosis factor-α were measured. Enumeration of circulating DCs (myeloid [m] and plasmocytoid [p]) and its surface antigen expression were quantified by flow cytometry.

RESULTS

The serum GM-CSF levels were significantly higher among diabetes subjects compared with subjects without diabetes and showed a positive correlation with glycated hemoglobin (r=0.208, P=0.018). The serum GM-CSF levels were lower in subjects on combined insulin and oral hypoglycemic agents (OHA) treatment (1.09 pg/mL) compared with those taking OHA alone (1.9 pg/mL). The increased GM-CSF levels were associated with the activated phenotype of mDCs and pDCs, as determined by up-regulation of the lineage markers.

CONCLUSION

The activated state of mDCs and pDCs seen among diabetes subjects might be due to the increased levels of GM-CSF and other pro-inflammatory cytokines.

Differentiation potential of CD14+ monocytes into myofibroblasts in patients with systemic sclerosis

Background

Circulating monocytes are a highly plastic and functionally heterogeneic cell type with an activated phenotype in patients with systemic sclerosis (SSc). CD14⁺ monocytes have the potential to differentiate into extra-cellular matrix (ECM) producing cells, possibly participating in fibrogenesis.

Aim

To study the effect of GM-CSF, IL-4 and endothelin -1 (ET-1) alone or in combination on monocyte differentiation into myofibroblasts.

Methods

CD14⁺ cells were isolated from peripheral blood from 14 SSc patients and healthy controls by positive selection and incubated with different combinations of GM-CSF, IL-4 and ET-1 for 14 days. Type-1 collagen and α-SMA were detected by Western blot, qPCR and confocal microscopy. HLA-DR, CD11c and CD14 expression was analysed by flow cytometry. A collagen gel contraction assay was performed for functional myofibroblast assessment.

Results

GM-CSF both induced collagen and α-SMA expression after 14 days. ET-1 further increased GM-CSF-induced collagen expression in a dose dependent manner up to 30-fold. IL-4/GM-CSF combination leads to a more DC-like phenotype of monocytes associated with reduced collagen and α-SMA expression compared to GM-CSF alone. Collagen and α-SMA expression was higher in monocytes from SSc patients and monocytes were more prone to obtain a spindle form. In contrast to controls, ET-1 and IL-4 alone were sufficient to induce α-SMA expression in monocytes from SSc patients. Despite the induction of α-SMA expression, monocyte-derived myofibroblasts only had a moderate capability of contraction in functional analyses.

Conclusion

SSc monocytes display increased maturation towards myofibroblasts demonstrated by their phenotype and α-SMA expression when compared to monocytes from healthy controls, however only with minor functional contraction properties.

Cytokine-based high log-scale expansion of functional human dendritic cells from cord-blood CD34-positive cells

Dendritic cells (DCs) play a crucial role in maintaining the immune system. Though DC-based cancer immunotherapy has been suggested as a potential treatment for various kinds of malignancies, its clinical efficacies are still insufficient in many human trials. Issues that limit the clinical efficacy of DC-based immunotherapy, as well as the difficulty of the industrial production of DCs, are largely due to the limited number of autologous DCs available from each patient. We here established a possible breakthrough, a simple cytokine-based culture method to expand the log-scale order of functional human DCs. Floating cultivation of cord-blood CD34(+) cells under an optimized cytokine cocktail led these progenitor cells to stable log-scale proliferation and to DC differentiation. The expanded DCs had typical features of conventional myeloid DCs in vitro. Therefore, the concept of DC expansion should contribute significantly to the progress of DC immunotherapy.

The GM-CSF receptor utilizes β-catenin and Tcf4 to specify macrophage lineage differentiation

Granulocyte-macrophage colony stimulating factor (GM-CSF) promotes the growth, survival, differentiation and activation of normal myeloid cells and is essential for fully functional macrophage differentiation in vivo. To better understand the mechanisms by which growth factors control the balance between proliferation and self-renewal versus growth-suppression and differentiation we have used the bi-potent FDB1 myeloid cell line, which proliferates in IL-3 and differentiates to granulocytes and macrophages in response to GM-CSF. This provides a manipulable model in which to dissect the switch between growth and differentiation. We show that, in the context of signaling from an activating mutant of the GM-CSF receptor β subunit, a single intracellular tyrosine residue (Y577) mediates the granulocyte fate decision. Loss of granulocyte differentiation in a Y577F second-site mutant is accompanied by enhanced macrophage differentiation and accumulation of β-catenin together with activation of Tcf4 and other Wnt target genes. These include the known macrophage lineage inducer, Egr1. We show that forced expression of Tcf4 or a stabilised β-catenin mutant is sufficient to promote macrophage differentiation in response to GM-CSF and that GM-CSF can regulate β-catenin stability, most likely via GSK3β. Consistent with this pathway being active in primary cells we show that inhibition of GSK3β activity promotes the formation of macrophage colonies at the expense of granulocyte colonies in response to GM-CSF. This study therefore identifies a novel pathway through which growth factor receptor signaling can interact with transcriptional regulators to influence lineage choice during myeloid differentiation.

Growth factors in ischemic stroke

Data from pre-clinical and clinical studies provide evidence that colony-stimulating factors (CSFs) and other growth factors (GFs) can improve stroke outcome by reducing stroke damage through their anti-apoptotic and anti-inflammatory effects, and by promoting angiogenesis and neurogenesis. This review provides a critical and up-to-date literature review on CSF use in stroke. We searched for experimental and clinical studies on haemopoietic GFs such as granulocyte CSF, erythropoietin, granulocyte-macrophage colony-stimulating factor, stem cell factor (SCF), vascular endothelial GF, stromal cell-derived factor-1α and SCF in ischemic stroke. We also considered studies on insulin-like growth factor-1 and neurotrophins. Despite promising results from animal models, the lack of data in human beings hampers efficacy assessments of GFs on stroke outcome. We provide a comprehensive and critical view of the present knowledge about GFs and stroke, and an overview of ongoing and future prospects.

Interferon-α in the generation of monocyte-derived dendritic cells: recent advances and implications for dermatology

Dendritic cells (DCs) have a critical role in antiviral responses, in autoimmune disease pathogenesis and in initiating and maintaining inflammatory skin disorders, and are candidates for cell-based immunotherapeutic approaches for tumours. Recent studies have shown the important role of type I interferons (IFNs) in DC differentiation and activation. In the presence of IFN-α and granulocyte/macrophage colony-stimulating factor monocytes differentiate into DCs referred to as IFN-DCs. In vitro generated IFN-DCs show a partially mature phenotype, are effective in taking up antigens, share features of myeloid DCs, plasmacytoid DCs and natural killer cells, exhibit an enhanced chemotactic response and are capable of migrating to the lymph nodes. IFN-DCs produce several chemokines and cytokines, including T-helper 1 (Th1) mediators belonging to the interleukin-12 family. IFN-DCs stimulate T- and B-cell responses and the production of IFN-γ in mixed lymphocyte reactions and have a capacity to produce IFN-γ themselves. IFN-DCs express several toll-like receptor (TLR) subtypes and TLR ligand stimulation improves their costimulatory molecule expression, increases their Th1 cytokine production and enhances their capacity to stimulate naive T-cell proliferation. Here we review the interaction of IFN-α and monocytes and the role of IFN-DCs in infections, in autoimmunity, in inflammation and in cancer immunotherapy focusing on dermatological conditions.

Low-dose paclitaxel enhances the anti-tumor efficacy of GM-CSF surface-modified whole-tumor-cell vaccine in mouse model of prostate cancer

Chemotherapy combined with a tumor vaccine is an attractive approach in cancer therapy. This study was designed to investigate the optimal schedule and mechanisms of action of a novel GM-CSF (granulocyte-macrophage colony-stimulating factor) surface-modified tumor-cell vaccine in combination with paclitaxel in the treatment of mouse RM-1 prostate cancer. First, the anti-tumor efficiencies of various dosage of paclitaxel (4, 20, 40 mg/kg) in combination with the vaccine in different administration sequences were examined in the mouse RM-1 prostate cancer model. Then, the in vivo and in vitro effects of various dosage of paclitaxel on RM-1 cells, T cells, and DCs (dendritic cells) were evaluated. The results showed that: (a) the GM-CSF-surface-modified tumor-cell vaccine was more potent at inducing the uptake of tumor antigens by DCs than irradiated tumor cells plus free GM-CSF; (b) 4 mg/kg paclitaxel combined with the GM-CSF-surface-modified tumor-cell vaccine was the most effective at enhancing tumor regression in RM-1 prostate cancer mice when the vaccine was administrated 2 days after paclitaxel; and (c) administration of 4 mg/kg paclitaxel followed by the vaccine induced the highest degree of CD8(+) T-cell infiltration in tumor tissue, suggesting that the induction of tumor-specific immune response had occurred. These findings suggested that the GM-CSF-surface-modified tumor-cell vaccine may have potential clinical benefit for patients with prostate cancer when it is combined with paclitaxel. Furthermore, the effect of immunochemotherapy depends on careful selection of paclitaxel dosage and the sequence of paclitaxel/vaccine administration.

15 kDa Granulysin versus GM-CSF for monocytes differentiation: analogies and differences at the transcriptome level

Background

Granulysin is an antimicrobial and proinflammatory protein with several isoforms. While the 9 kDa isoform is a well described cytolytic molecule with pro-inflammatory activity, the functions of the 15 kDa isoform is less well understood. Recently it was shown that 15 kDa Granulysin can act as an alarmin that is able to activate monocytes and immature dendritic cells. Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) is a growth factor widely used in immunotherapy both for in vivo and ex vivo applications, especially for its proliferative effects.

Methods

We analyzed gene expression profiles of monocytes cultured with 15 kDa Granulysin or GM-CSF for 4, 12, 24 and 48 hours to unravel both similarities and differences between the effects of these stimulators.

Results

The analysis revealed a common signature induced by both factors at each time point, but over time, a more specific signature for each factor became evident. At all time points, 15 kDa Granulysin induced immune response, chemotaxis and cell adhesion genes. In addition, only 15 kDa Granulsyin induced the activation of pathways related to fundamental dendritic cell functions, such as co-stimulation of T-cell activation and Th1 development. GM-CSF specifically down-regulated genes related to cell cycle arrest and the immune response. More specifically, cytokine production, lymphocyte mediated immunity and humoral immune response were down-regulated at late time points.

Conclusion

This study provides important insights on the effects of a novel agent, 15 kDa granulysin, that holds promise for therapeutic applications aimed at the activation of the immune response.