Enhanced dendritic cell maturation by TNF-alpha or cytidine-phosphate-guanosine DNA drives T cell activation in vitro and therapeutic anti-tumor immune responses in vivo

Cationic pH-sensitive liposomes as tuberculosis subunit vaccine delivery systems: Effect of liposome composition on cellular innate immune responses

Tuberculosis (TB) is a major global health problem, and the development of effective and safe vaccines is urgently needed. CD8+ T-cells play an important role alongside CD4+ T-cells in the protective immune response against TB. pH-sensitive liposomes are hypothesized to boost CD8+ T-cell responses by promoting class I presentation through a mechanism involving pH-dependent endosomal escape and the cytosolic transfer of antigens. The aim of the study was to explore the potential of pH-sensitive liposomes as a novel delivery system for a multi-stage protein subunit vaccine against TB in primary human cells. The liposomes were formulated with the fusion antigen Ag85b-ESAT6-Rv2034 (AER), which was previously shown to be effective in reducing bacterial load in the lungs HLA-DR3 transgenic mice and guinea pigs. The liposomes were assessed in vitro for cellular uptake, cell viability, upregulation of cell surface activation markers, induction of cytokine production using human monocyte-derived dendritic cells (MDDCs), and activation of human antigen-specific T-cells. Liposome DOPC:DOPE:DOBAQ:EPC (3:5:2:4 M ratio) was effectively taken up, induced several cell surface activation markers, and production of CCl3, CCL4, and TNFα in MDDCs. It also induced upregulation of CD154 and IFNγ in T-cell clones in an antigen-specific manner. Thus, cationic pH-sensitive liposome-based TB vaccines have been demonstrated to be capable of inducing robust protective Mtb-specific immune responses, positioning them as promising candidates for effectiveTBvaccination.

HERV-W envelope protein is present in microglial cells of the human glioma tumor microenvironment and differentially modulates neoplastic cell behavior

Gliomas are the most common parenchymal tumors of the central nervous system (CNS). With regard to their still unclear etiology, several recent studies have provided evidence of a new category of pathogenic elements called human endogenous retroviruses (HERVs) which seem to contribute to the evolution and progression of many neurological diseases such as amyotrophic lateral sclerosis (ALS), schizophrenia, chronic inflammatory polyneuropathy (CIDP) and, particularly, multiple sclerosis (MS). In these diseases, HERVs exert effects on cellular processes such as inflammation, proliferation, and migration. In previous studies, we demonstrated that in MS, the human endogenous retrovirus type-W envelope protein (HERV-W ENV) interferes with lesion repair through the activation of microglia (MG), the innate myeloid immune cells of the CNS. Here, we now show that HERV-W ENV is also present in the microglial cells (MG) of the tumor microenvironment (TME) in gliomas. It modulates the behavior of glioblastoma (GBM) cell lines in GBM/MG cocultures by altering their gene expression, secreted cytokines, morphology, proliferation, and migration properties and could thereby contribute to key tumor properties.

Bacillus toyonensis amplifies the immunogenicity of an experimental recombinant tetanus vaccine in horses

Probiotic microorganisms can stimulate an immune response and increase the efficiency of vaccines. For example, Bacillus toyonensis is a nonpathogenic, Gram-positive bacterium that has been used as a probiotic in animal supplementation. It induces immunomodulatory effects and increases the vaccine response in several species. This study aimed to evaluate the effect of B. toyonensis supplementation on the modulation of the immune response in horses vaccinated with recombinant Clostridium tetani toxin. Twenty horses were vaccinated twice, with an interval of 21 days between doses, and equally divided into two groups: the first group was supplemented orally for 42 days with feed containing viable spores of B. toyonensis (1 × 108) mixed with molasses (40 ml), starting 7 days before the first vaccination; the second (control) group received only feed mixed with molasses, starting 7 days before the first vaccination. Serum samples were collected to evaluate the humoral immune response using an in-house indirect enzyme-linked immunosorbent assay (ELISA), and peripheral blood mononuclear cells (PBMCs) were collected to evaluate cytokine transcription (qPCR). For the specific IgG-anti-rTENT titer, the supplemented group had ELISA values that were four times higher than those of the control group (p < 0.05). The supplemented group also showed higher ELISA values for the IgGa and IgGT sub-isotypes compared to the control group. In PBMCs stimulated with B. toyonensis, relative cytokine transcription of the supplemented group showed 15-, 8-, 7-, and 6-fold increases for IL1, TNFα, IL10 and IL4, respectively. When stimulated with a vaccine antigen, the supplemented group showed 1.6-, 1.8-, and 0.5-fold increases in IL1, TNFα, and IL4, respectively, compared to the control group. Horses supplemented with B. toyonensis had a significantly improved vaccine immune response compared to those in the control group, which suggests a promising approach for improving vaccine efficacy with probiotics.

Genetically Engineered Cytomembrane Nanovaccines for Cancer Immunotherapy

Cancer nanovaccines have attracted widespread attention by inducing potent cytotoxic T cell responses to improve immune checkpoint blockade (ICB) therapy, while the lack of co-stimulatory molecules limits their clinical applications. Here, a genetically engineered cancer cytomembrane nanovaccine is reported that simultaneously overexpresses co-stimulatory molecule CD40L and immune checkpoint inhibitor PD1 to elicit robust antitumor immunity for cancer immunotherapy. The CD40L and tumor antigens inherited from cancer cytomembranes effectively stimulate dendritic cell (DC)-mediated immune activation of cytotoxic T cells, while the PD1 on cancer cytomembranes significantly blocks PD1/PD-L1 signaling pathway, synergistically stimulating antitumor immune responses. Benefiting from the targeting ability of cancer cytomembranes, this nanovaccines formula shows an enhanced lymph node trafficking and retention. Compared with original cancer cytomembranes, this genetically engineered nanovaccine induces twofold DC maturation and shows satisfactory precaution efficacy in a breast tumor mouse model. This genetically engineered cytomembrane nanovaccine offers a simple, safe, and robust strategy by incorporating cytomembrane components and co-stimulatory molecules for enhanced cancer immunotherapy.

Immunoinformatics Approach to Design a Chimeric CD70-Peptide Vaccine against Renal Cell Carcinoma

Renal cell carcinoma (RCC) accounts for the majority of cancer-related deaths worldwide. Overexpression of CD70 has been linked to advanced stages of RCC. Therefore, this study aims to develop a multiepitope vaccine targeting the overexpressed CD70 using immunoinformatics techniques. In this investigation, in silico multiepitope vaccines were constructed by linking specific CD70 protein epitopes for helper T lymphocytes and CD8+ T lymphocytes. To enhance immunogenicity, sequences of cell-penetrating peptide (CPP), penetratin (pAntp), along with the entire sequence of tumor necrosis factor-α (TNF-α), were attached to the N-terminal and C-terminal of the CD70 epitopes. Computational assessments were performed on these chimeric vaccines for antigenicity, allergenicity, peptide toxicity, population coverage, and physicochemical properties. Furthermore, refined 3D constructs were subjected to a range of analyses, encompassing structural B-cell epitope prediction and molecular docking. The chosen vaccine construct underwent diverse assessments such as molecular dynamics simulation, immune response simulation, and in silico cloning. All vaccines comprised antigenic, nontoxic, and nonallergenic epitopes, ensuring extensive global population coverage. The vaccine constructs demonstrated favorable physicochemical characteristics. The binding affinity of chimeric vaccines to the TNF receptor remained relatively stable, influenced by the alignment of vaccine components. Molecular docking and dynamics analyses predicted stable interactions between CD70-CPP-TNF and the TNF receptor, indicating potential efficacy. In silico codon optimization and cloning of the vaccine nucleic acid sequence were accomplished using the pET28a plasmid. Furthermore, this vaccine displayed the capacity to modulate humoral and cellular immune responses. Overall, the results suggest therapeutic potential for the chimeric CD70-CPP-TNF vaccine against RCC. However, validation through in vitro and in vivo experiments is necessary. This trial is registered with NCT04696731 and NCT04046445.

The deubiquitinating enzyme OTUD7b protects dendritic cells from TNF-induced apoptosis by stabilizing the E3 ligase TRAF2

The cytokine tumor necrosis factor (TNF) critically regulates the intertwined cell death and pro-inflammatory signaling pathways of dendritic cells (DCs) via ubiquitin modification of central effector molecules, but the intrinsic molecular switches deciding on either pathway are incompletely defined. Here, we uncover that the ovarian tumor deubiquitinating enzyme 7b (OTUD7b) prevents TNF-induced apoptosis of DCs in infection, resulting in efficient priming of pathogen-specific CD8⁺ T cells. Mechanistically, OTUD7b stabilizes the E3 ligase TNF-receptor-associated factor 2 (TRAF2) in human and murine DCs by counteracting its K48-ubiquitination and proteasomal degradation. TRAF2 in turn facilitates K63-linked polyubiquitination of RIPK1, which mediates activation of NF-κB and MAP kinases, IL-12 production, and expression of anti-apoptotic cFLIP and Bcl-xL. We show that mice with DC-specific OTUD7b-deficiency displayed DC apoptosis and a failure to induce CD8⁺ T cell-mediated brain pathology, experimental cerebral malaria, in a murine malaria infection model. Together, our data identify the deubiquitinating enzyme OTUD7b as a central molecular switch deciding on survival of human and murine DCs and provides a rationale to manipulate DC responses by targeting their ubiquitin network downstream of the TNF receptor pathway.

Melatonin attenuates lipopolysaccharide-induced immune dysfunction in dendritic cells

Melatonin, a ubiquitous hormone, is principally secreted from pineal gland in mammals and possesses strong antioxidant and anti-inflammatory properties. However, its specific roles in the immune functions of dendritic cells (DCs) during acute lung injury (ALI) remain unknown. In this study, we found that melatonin restored the body weight, decreased the lung weight/body weight ratio, alleviated the histopathological lung injury, and decreased the levels of cytokines (tumor necrosis factor-α (TNF-α), interleukin (IL)-12p70, IL-17, and IL-10) in bronchoalveolar lavage fluid of the lipopolysaccharide (LPS)-induced ALI murine model. Moreover, melatonin inhibited the major histocompatibility complex II (MHCII) expression of lung CD11b⁺ DCs after LPS challenge in vivo. In vitro, melatonin reversed the shape index, promoted the endocytosis, and inhibited phenotypic expression of MHCII, CD40, CD80, and CD86 in LPS-activated DCs. Furthermore, melatonin decreased the expression of an activated marker, CD69, and the secretion of pro-inflammatory cytokines (TNF-α, IL-12p70, and IL-17) after LPS challenge. It hampered the LPS-activated DCs migration by downregulating the C-C chemokine receptor 7 (CCR7) expression, and then weakened the ability of LPS-induced DCs to stimulate allogeneic CD4⁺ T cell proliferation. Melatonin shaped the immune function of DCs in a nuclear factor erythroid-2-related factor 2 (Nrf-2)/heme oxygenase-1 (HO-1) axis-dependent manner. These findings indicate that melatonin protects DCs from ALI-induced immunological stress and may be used to develop novel DC-targeting strategies for ALI therapy.

Activation, Amplification, and Ablation as Dynamic Mechanisms of Dendritic Cell Maturation

T cell responses to cognate antigens crucially depend on the specific functionality of dendritic cells (DCs) activated in a process referred to as maturation. Maturation was initially described as alterations of the functional status of DCs in direct response to multiple extrinsic innate signals derived from foreign organisms. More recent studies, conducted mainly in mice, revealed an intricate network of intrinsic signals dependent on cytokines and various immunomodulatory pathways facilitating communication between individual DCs and other cells for the orchestration of specific maturation outcomes. These signals selectively amplify the initial activation of DCs mediated by innate factors and dynamically shape DC functionalities by ablating DCs with specific functions. Here, we discuss the effects of the initial activation of DCs that crucially includes the production of cytokine intermediaries to collectively achieve amplification of the maturation process and further precise sculpting of the functional landscapes among DCs. By emphasizing the interconnectedness of the intracellular and intercellular mechanisms, we reveal activation, amplification, and ablation as the mechanistically integrated components of the DC maturation process.

The molecular basis of immuno-radiotherapy

PURPOSE

Radiotherapy (RT) and immunotherapy are powerful anti-tumor treatment modalities. Experimental research has demonstrated an important interplay between the cytotoxic effects of RT and the immune system. This systematic review provides an overview of the basics of anti-tumor immunity and focuses on the mechanisms underlying the interplay between RT and immune anti-tumor response that set the molecular basis of immuno-RT.

CONCLUSIONS

An 'immunity acquired equilibrium' mimicking tumor dormancy can be achieved post-irradiation treatment, with the balance shifted toward tumor eradication or regrowth when immune cells' cytotoxic effects or cancer proliferation rate prevail, respectively. RT has both immunosuppressive and immune-enhancing properties. The latter effect is also known as radio-vaccination. Its mechanisms involve up- or down-regulation of membrane molecules, such as PD-L1, HLA-class-I, CD80/86, CD47, and Fas/CD95, that play a vital role in immune checkpoint pathways and increased cytokine expression (e.g. INFα,β,γ, IL1,2, and TNFα) by cancer or immune cells. Moreover, the interactions of radiation with the tumor microenvironment (fibroblasts, tumor-infiltrating lymphocytes, monocytes, and dendritic cells are also an important component of radio-vaccination. Thus, RT may have anti-tumor vaccine properties, whose sequels can be exploited by immunotherapy agents to treat different cancer subtypes effectively.

In vitro Characterization of Enhanced Human Immune Responses by GM-CSF Encoding HSV-1-Induced Melanoma Cells

PURPOSE

We studied the innate and adaptive immune response against melanoma cells after JS-1 (wild-type herpes simplex virus 1, wt HSV-1) or Talimogene laherparepvec (T-VEC) infection and evaluated the antitumoral efficacy in human melanoma cells. We analyzed the putative synergistic biological and immunological effects of JS-1 or T-VEC combined with cytostatic drugs in human tumor and immune cells. T-VEC is a genetically modified strain of HSV-1. Genetic modifications (insertion of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene) were made to attenuate the virus and increase selectivity for cancer cells. In addition to the direct oncolytic effect, we investigated the immune stimulatory effects of T-VEC by comparing it with JS-1. JS-1 is identical T-VEC except for the inserted GM-CSF gene.

MATERIALS AND METHODS

We analyzed the effects of T-VEC and JS-1 with cytostatic drugs in human tumor-immune cell coculture experiments. After coculture, the surface markers CD80, CD83 and CD86 were measured by fluorescence-activated cell sorting and the cytokines, interleukin (IL)-2, IL-6, tumor necrosis factor (TNF)-α and GM-CSF, by enzyme-linked immunosorbent assays. Furthermore, we analyzed the potential of the viruses to induce T cell activation, measured on the basis of CD4, CD8 and CD69. Analysis of these markers and cytokines allows for conclusions to be drawn concerning the maturation of dendritic cells (DCs) and the immunostimulatory effects of the treatment.

RESULTS

We documented increased activation of human cytotoxic T lymphocytes after infection by both HSV-1 strains and treatment with cytostatic drugs without significant differences between T-VEC and JS-1.

CONCLUSION

We demonstrated an immune response as a result of infection with both viruses, but T-VEC was in vitro not stronger than JS-1. The immunostimulatory effects of the viruses could be partially increased by chemotherapy, providing a rationale for future preclinical studies designed to explore T-VEC in combined regimens.

The Th1/Tfh-like biased responses elicited by the rASP-1 innate adjuvant are dependent on TRIF and Type I IFN receptor pathways

Ov-ASP-1 (rASP-1), a parasite-derived protein secreted by the helminth Onchocerca volvulus, is an adjuvant which enhances the potency of the influenza trivalent vaccine (IIV3), even when used with 40-fold less IIV3. This study is aimed to provide a deeper insight into the molecular networks that underline the adjuvanticity of rASP-1. Here we show that rASP-1 stimulates mouse CD11c+ bone marrow-derived dendritic (BMDCs) to secrete elevated levels of IL-12p40, TNF-α, IP-10 and IFN-β in a TRIF-dependent but MyD88-independent manner. rASP-1-activated BMDCs promoted the differentiation of naïve CD4+ T cells into Th1 cells (IFN-γ+) that was TRIF- and type I interferon receptor (IFNAR)-dependent, and into Tfh-like cells (IL21+) and Tfh1 (IFN-γ+ IL21+) that were TRIF-, MyD88- and IFNAR-dependent. rASP-1-activated BMDCs promoted the differentiation of naïve CD4+ T cells into Th17 (IL-17+) cells only when the MyD88 pathway was inhibited. Importantly, rASP-1-activated human blood cDCs expressed upregulated genes that are associated with DC maturation, type I IFN and type II IFN signaling, as well as TLR4-TRIF dependent signaling. These activated cDCs promoted the differentiation of naïve human CD4+ T cells into Th1, Tfh-like and Th17 cells. Our data thus confirms that the rASP-1 is a potent innate adjuvant that polarizes the adaptive T cell responses to Th1/Tfh1 in both mouse and human DCs. Notably, the rASP-1-adjuvanted IIV3 vaccine elicited protection of mice from a lethal H1N1 infection that is also dependent on the TLR4-TRIF axis and IFNAR signaling pathway, as well as on its ability to induce anti-IIV3 antibody production.

TNF-α sculpts a maturation process in vivo by pruning tolerogenic dendritic cells

It remains unclear how the pro-immunogenic maturation of conventional dendritic cells (cDCs) abrogates their tolerogenic functions. Here, we report that the loss of tolerogenic functions depends on the rapid death of BTLAhi cDC1s, which, in the steady state, are present in systemic peripheral lymphoid organs and promote tolerance that limits subsequent immune responses. A canonical inducer of maturation, lipopolysaccharide (LPS), initiates a burst of tumor necrosis factor alpha (TNF-α) production and the resultant acute death of BTLAhi cDC1s mediated by tumor necrosis factor receptor 1. The ablation of these individual tolerogenic cDCs is amplified by TNF-α produced by neighboring cells. This loss of tolerogenic cDCs is transient, accentuating the restoration of homeostatic conditions through biological turnover of cDCs in vivo. Therefore, our results reveal that the abrogation of tolerogenic functions during an acute immunogenic maturation depends on an ablation of the tolerogenic cDC population, resulting in a dynamic remodeling of the cDC functional landscape.

Multiple Faces of the Glioblastoma Microenvironment

The tumor microenvironment is a highly dynamic accumulation of resident and infiltrating tumor cells, responsible for growth and invasion. The authors focused on the leading-edge concepts regarding the glioblastoma microenvironment. Due to the fact that the modern trend in the research and treatment of glioblastoma is represented by multiple approaches that target not only the primary tumor but also the neighboring tissue, the study of the microenvironment in the peritumoral tissue is an appealing direction for current and future therapies.

Homeoprotein SIX1 compromises antitumor immunity through TGF-β-mediated regulation of collagens

The tumor microenvironment (TME), including infiltrated immune cells, is known to play an important role in tumor growth; however, the mechanisms underlying tumor immunogenicity have not been fully elucidated. Here, we discovered an unexpected role for the transcription factor SIX1 in regulating the tumor immune microenvironment. Based on analyses of patient datasets, we found that SIX1 was upregulated in human tumor tissues and that its expression levels were negatively correlated with immune cell infiltration in the TME and the overall survival rates of cancer patients. Deletion of Six1 in cancer cells significantly reduced tumor growth in an immune-dependent manner with enhanced antitumor immunity in the TME. Mechanistically, SIX1 was required for the expression of multiple collagen genes via the TGFBR2-dependent Smad2/3 activation pathway, and collagen deposition in the TME hampered immune cell infiltration and activation. Thus, our study uncovers a crucial role for SIX1 in modulating tumor immunogenicity and provides proof-of-concept evidence for targeting SIX1 in cancer immunotherapy.

Virus-Mimic mRNA Vaccine for Cancer Treatment

An effective therapeutic cancer vaccine should be empowered with the capacity to overcome the immunosuppressive tumor microenvironment. Here, the authors describe a mRNA virus-mimicking vaccine platform that is comprised of a phospholipid bilayer encapsulated with a protein-nucleotide core consisting of antigen-encoding mRNA molecules, unmethylated CpG oligonucleotides and positively charged proteins. In cell culture, VLVP potently stimulated bone marrow-derived dendritic cells (BMDCs) to express inflammatory cytokines that facilitated dendritic cell (DC) maturation and promoted antigen processing and presentation. In tumor-bearing mice, VLVP treatment stimulated proliferation of antigen-specific CD8+T cells in the lymphatic organs and T cell infiltration into the tumor bed, resulting in potent anti-tumor immunity. Cytometry by time of flight (CyTOF) analysis revealed that VLVP treatment stimulated a 5-fold increase in tumor-associated CD8+DCs and a 4-fold increase in tumorinfiltrated CD8+T cells, with concurrent decreases in tumor-associated bone marrow-derived suppressor cells and arginase 1- expressing suppressive DCs. Finally, CpG oligonucleotide is an essential adjuvant for vaccine activity. Inclusion of CpG not only maximized vaccine activity but also prevented PD-1 expression in T cells, serving the dual roles as a potent adjuvant and a checkpoint blockade agent.

Tumor necrosis factor inhibitors as therapeutic agents for recurrent spontaneous abortion (Review)

Recurrent spontaneous abortion (RSA) is a troublesome pregnancy disorder that manifests as sequential early pregnancy losses; its causes are diverse and complex. Among the known possible causes of RSA, the development of an immune disorder in response to the embryo appears to be the most pronounced. The imbalance between immune rejection and immune tolerance contributes to pregnancy loss in females with RSA, wherein the abnormal ratio of T helper (Th)1 cell‑related cytokines [predominantly tumor necrosis factor (TNF)‑α] and Th2 cell‑related cytokines is a strong risk factor for RSA. TNF‑α is a pro‑inflammatory cytokine and TNF inhibitors have been effective in the treatment of various autoimmune diseases, such as ankylosing spondylitis, and inflammatory diseases, such as ulcerative colitis. Based on their immunomodulatory properties, TNF inhibitors have been used in the treatment of RSA to reduce the immune rejection rate and improvement in pregnancy outcomes has been observed in females suffering from RSA who were treated with TNF inhibitors. The aim of the present review was to interpret the involvement of TNF‑α in the immunological disorder underlying RSA and summarize the clinical outcomes of TNF inhibitor treatment in patients with RSA.

Immune response of adult horses, pregnant mares and foals to an experimental vaccine with recombinant EMA-2 protein of Theileria equi

Equine theileriosis, caused by the Theileria equi protozoan, is a disease of worldwide importance. T. equi expresses surface proteins, of which the EMA-2 protein is a promising antigen for vaccine use. The aim of this study was to evaluate the immune response of adult horses, pregnant mares, and foals to an experimental EMA-2 protein of recombinant T. equi vaccine. A total of 46 horses were used in this study for vaccine trials and challenges. Twelve geldings, 14 pregnant mares, and 14 foals were divided into vaccinated and control groups. Total serum specific anti-rEMA-2 IgG, IgG subclasses, and transcription of cytokines related to the immune response were evaluated. For the vaccine challenge, six six-month-old foals were divided into vaccinated and control groups. For the challenge, blood from a horse with theileriosis was transfused to the foals. Geldings and pregnant mares maintained anti-rEMA-2 IgG levels at 130 and 140 days after vaccination, respectively. The most-detected IgG subclasses in vaccinated were IgG3/5, IgG4/7, and IgG1. IL2, IL10, IL12, IL17, IFN-γ, and TNF-α were the most-transcribed cytokines in PBMCs of vaccinated horses stimulated with rEMA-2. Challenge with T. equi demonstrated that vaccinated foals had an increase of 33% in total IgG four days after blood transfusion, while control foals had no significant response, suggesting that vaccine antibodies may have recognized EMA-2 protein of the native T. equi antigen. T. equi recombinant EMA-2 was shown to be a promising vaccine antigen by inducing humoral and cellular immunity similar to that observed in natural parasite infections.

Localized hydrogel delivery of dendritic cells for attenuation of multiple sclerosis in a murine model

In multiple sclerosis (MS), abnormally activated immune cells responsive to myelin proteins result in widespread damage throughout the central nervous system (CNS) and ultimately irreversible disability. Immunomodulation by delivering dendritic cells (DCs) utilizes a potent and rapid MS disease progression driver therapeutically. Here, we investigated delivering DCs for disease severity attenuation using an experimental autoimmune encephalomyelitis preclinical MS model. DCs treated with interleukin-10 (IL-10) (DC10s) were transplanted using in situ gelling poly(ethylene glycol)-based hydrogel for target site localization. DC delivery increased hydrogel longevity and altered the injection site recruited, endogenous immune cell profile within 2 days postinjection. Furthermore, hydrogel-mediated DC transplantation efficacy depended on the injection-site. DCs delivered to the neck local to MS-associated CNS-draining cervical lymph nodes attenuated paralysis, compared to untreated controls, while delivery to the flank did not alter paralysis severity. This study demonstrates that local delivery of DC10s modulates immune cell recruitment and attenuates disease progression in a preclinical model of MS.

A Novel Thienopyrimidine Analog, TPH104, Mediates Immunogenic Cell Death in Triple-Negative Breast Cancer Cells

Simple Summary

Triple-negative breast cancer (TNBC) is the most lethal and aggressive subtype of breast cancer that lacks an estrogen receptor, the progesterone receptor and the human epidermal growth factor receptor 2 (HER2), making it unsuitable for hormonal- or HER2-based therapy. TNBC is known for its higher relapse rate, poorer prognosis and higher rate of metastasis compared to non-TNBC because although patients initially respond to chemotherapy that kills cancer cells through a form of programmed cell death called apoptosis, they later develop chemoresistance and stop responding to the treatment, accounting for one fourth of all breast cancer deaths. In this study, we report a novel compound, TPH104, that elicits a unique, non-apoptotic cell death in TNBC cells. Upon treatment with TPH104, TNBC cells swell and burst, releasing immunogenic markers that alert and activate the immune system to further recognize and attack the neighboring breast cancer cells.

Abstract

Enhancing the tumor immunogenic microenvironment has been suggested to circumvent triple-negative breast cancer (TNBC) resistance and increase the efficacy of conventional chemotherapy. Here, we report a novel chemotherapeutic compound, TPH104, which induces immunogenic cell death in the TNBC cell line MDA-MB-231, by increasing the stimulatory capacity of dendritic cells (DCs), with an IC₅₀ value of 140 nM. TPH104 (5 µM) significantly increased ATP levels in the supernatant and mobilized intracellular calreticulin to the plasma membrane in MDA-MB-231 cells, compared to cells incubated with the vehicle. Incubating MDA-MB-231 cells for 12 h with TPH104 (1–5 µM) significantly increased TNF-α mRNA levels. The supernatants of dying MDAMB-231 cells incubated with TPH104 increased mouse bone marrow-derived DC maturation, the expression of MHC-II and CD86 and the mRNA expression of TNF-α, IL-6 and IL-12. Overall, these results indicate that TPH104 induces immunogenic cell death in TNBC cells, in part, by activating DCs.

Harnessing Tumor Necrosis Factor Alpha to Achieve Effective Cancer Immunotherapy

Tumor necrosis factor alpha (TNFα) is a pleiotropic cytokine known to have contradictory roles in oncoimmunology. Indeed, TNFα has a central role in the onset of the immune response, inducing both activation and the effector function of macrophages, dendritic cells, natural killer (NK) cells, and B and T lymphocytes. Within the tumor microenvironment, however, TNFα is one of the main mediators of cancer-related inflammation. It is involved in the recruitment and differentiation of immune suppressor cells, leading to evasion of tumor immune surveillance. These characteristics turn TNFα into an attractive target to overcome therapy resistance and tackle cancer. This review focuses on the diverse molecular mechanisms that place TNFα as a source of resistance to immunotherapy such as monoclonal antibodies against cancer cells or immune checkpoints and adoptive cell therapy. We also expose the benefits of TNFα blocking strategies in combination with immunotherapy to improve the antitumor effect and prevent or treat adverse immune-related effects.

Small Molecule Enhancers of Endosome-to-Cytosol Import Augment Anti-tumor Immunity

Cross-presentation of antigens by dendritic cells (DCs) is critical for initiation of anti-tumor immune responses. Yet, key steps involved in trafficking of antigens taken up by DCs remain incompletely understood. Here, we screen 700 US Food and Drug Administration (FDA)-approved drugs and identify 37 enhancers of antigen import from endolysosomes into the cytosol. To reveal their mechanism of action, we generate proteomic organellar maps of control and drug-treated DCs (focusing on two compounds, prazosin and tamoxifen). By combining organellar mapping, quantitative proteomics, and microscopy, we conclude that import enhancers undergo lysosomal trapping leading to membrane permeation and antigen release. Enhancing antigen import facilitates cross-presentation of soluble and cell-associated antigens. Systemic administration of prazosin leads to reduced growth of MC38 tumors and to a synergistic effect with checkpoint immunotherapy in a melanoma model. Thus, inefficient antigen import into the cytosol limits antigen cross-presentation, restraining the potency of anti-tumor immune responses and efficacy of checkpoint blockers.

Intranasal delivery of cationic liposome-protamine complex mRNA vaccine elicits effective anti-tumor immunity

Immunization with synthetic mRNA encoding tumor-associated antigens is an emerging vaccine strategy for the treatment of cancer. In order to prevent mRNA degradation, promote antigen-presenting cells antigen presentation, and induce an anti-tumor immune response, we investigated the nasal administration of mRNA vaccines with positively charged protamine to concentrate mRNA, form a stable polycation-mRNA complex, and encapsulate the complex with DOTAP/Chol/DSPE-PEG cationic liposomes. Cationic liposome/protamine complex (LPC) showed significantly greater efficiency in uptake of vaccine particles in vitro and stronger capacities to stimulate dendritic cell maturation, which further induced a potent anti-tumor immune response. Intranasal immunization of mice with cationic LPC containing mRNA encoding cytokeratin 19 provoked a strong cellular immune response and slowed tumor growth in an aggressive Lewis lung cancer model. The results of this study provide evidence that cationic LPC can be used as a safe and effective adjuvant and this mRNA formulation provides a basis for anti-cancer vaccination of humans.

CDK7 Inhibition Potentiates Genome Instability Triggering Anti-tumor Immunity in Small Cell Lung Cancer

Cyclin-dependent kinase 7 (CDK7) is a central regulator of the cell cycle and gene transcription. However, little is known about its impact on genomic instability and cancer immunity. Using a selective CDK7 inhibitor, YKL-5-124, we demonstrated that CDK7 inhibition predominately disrupts cell-cycle progression and induces DNA replication stress and genome instability in small cell lung cancer (SCLC) while simultaneously triggering immune-response signaling. These tumor-intrinsic events provoke a robust immune surveillance program elicited by T cells, which is further enhanced by the addition of immune-checkpoint blockade. Combining YKL-5-124 with anti-PD-1 offers significant survival benefit in multiple highly aggressive murine models of SCLC, providing a rationale for new combination regimens consisting of CDK7 inhibitors and immunotherapies.

Cytomembrane nanovaccines show therapeutic effects by mimicking tumor cells and antigen presenting cells

Most cancer vaccines are unsuccessful in eliciting clinically relevant effects. Without using exogenous antigens and adoptive cells, we show a concept of utilizing biologically reprogrammed cytomembranes of the fused cells (FCs) derived from dendritic cells (DCs) and cancer cells as tumor vaccines. The fusion of immunologically interrelated two types of cells results in strong expression of the whole tumor antigen complexes and the immunological co-stimulatory molecules on cytomembranes (FMs), allowing the nanoparticle-supported FM (NP@FM) to function like antigen presenting cells (APCs) for T cell immunoactivation. Moreover, tumor-antigen bearing NP@FM can be bio-recognized by DCs to induce DC-mediated T cell immunoactivation. The combination of these two immunoactivation pathways offers powerful antitumor immunoresponse. Through mimicking both APCs and cancer cells, this cytomembrane vaccine strategy can develop various vaccines toward multiple tumor types and provide chances for accommodating diverse functions originating from the supporters.

A translational concept of immuno-radiobiology

BACKGROUND

Traditional concepts of radiobiology model the direct radiation-induced cellular cytotoxicity but are not focused on late and sustained effects of radiation. Recent experimental data show the close involvement of immunological processes.

METHODS

Based on systematic PubMed searches, experimental data on immunological radiation effects are summarized and analyzed in a non-quantitative descriptive manner to provide a translational perspective on the immuno-modulatory impact of radiation in cancer.

RESULTS

Novel experimental findings document that sustained radiation effects are ultimately mediated through systemic factors such as cytotoxic CD8+ T cells and involve a local immuno-stimulation. Increased tumor infiltration of CD8+ T cell is a prerequisite for long-term radiation effects. CD8+ T cell depletion induces radio-resistance in experimental tumors. The proposed sequence of events involves radiation-damaged cells that release HMGB1, which activates macrophages via TLR4 to a local immuno-stimulation via TNF, which contributes to maturation of DCs. The mature DCs migrate to lymph nodes where they trigger effective CD8+ T cell responses. Radiation effects are boosted, when the physiological self-terminating negative feedback of immune reactions is antagonised via blocking of TGF-β or via checkpoint inhibition with involvement of CD8+ T cells as common denominator.

CONCLUSION

The concept of immuno-radiobiology emphasizes the necessity for a functional integrity of APCs and T cells for the long-term effects of radiotherapy. Local irradiation at higher doses induces tumor infiltration of CD8+ T cells, which can be boosted by immunotherapy. More systematic research is warranted to better understand the immunological effects of escalating radiation doses.

PD-1 Blockade Following Isolated Limb Perfusion with Vaccinia Virus Prevents Local and Distant Relapse of Soft-tissue Sarcoma

PURPOSE

The prevention and treatment of metastatic sarcoma are areas of significant unmet need. Immune checkpoint inhibitor monotherapy has shown little activity in sarcoma and there is great interest in identifying novel treatment combinations that may augment responses. In vitro and in vivo, we investigated the potential for an oncolytic vaccinia virus (GLV-1h68) delivered using isolated limb perfusion (ILP) to promote antitumor immune responses and augment response to PD-1 blockade in sarcoma.Experimental Design: In an established animal model of extremity sarcoma, we evaluated the potential of locoregional delivery of a vaccinia virus (GLV-1h68) alongside biochemotherapy (melphalan/TNFα) in ILP. Complementary in vitro assays for markers of immunogenic cell death were performed in sarcoma cell lines.

RESULTS

PD-1 monotherapy had minimal efficacy in vivo, mimicking the clinical scenario. Pretreatment with GLV-1h68 delivered by ILP (viral ILP) significantly improved responses. Furthermore, when performed prior to surgery and radiotherapy, viral ILP and PD-1 blockade prevented both local and distant relapse, curing a previously treatment-refractory model. Enhanced therapy was associated with marked modulation of the tumor microenvironment, with an increase in the number and penetrance of intratumoral CD8+ T cells and expansion and activation of dendritic cells. GLV-1h68 was capable of inducing markers of immunogenic cell death in human sarcoma cell lines.

CONCLUSIONS

Viral ILP augments the response to PD-1 blockade, transforming this locoregional therapy into a potentially effective systemic treatment for sarcoma and warrants translational evaluation.

Addressing the Adult Soft Tissue Sarcoma Microenvironment with Intratumoral Immunotherapy

Sarcoma is comprised of a heterogeneous group of tumors originating from the mesenchyme. Sarcoma is also the first tumor that responded to immunotherapeutic agents often termed as “Coley's toxins.” However, immunotherapy is yet to establish its presence in sarcomas. Complex interactions between tumor and immune cells in the tumor microenvironment play a crucial role in response to immunotherapy. There is a dynamic equilibrium created by the immune cells infiltrating the tumor, and this forms the basis of tumor evasion. Manipulating the intratumoral microenvironment will help overcome tumor evasion.

Highly enhanced cancer immunotherapy by combining nanovaccine with hyaluronidase

Tumor vaccine has been one of the research hotspots for cancer immunotherapy in recent years. By introducing tumor antigens into the body, the patient's own immune system will be specifically activated to induce effective immune responses for controlling or eliminating the malignant tumor cells. In this study, a simple nanovaccine was developed to induce antigen-specific anti-tumor immune responses. Polycationic polyethylenimine (PEI) was utilized to co-deliver the antigen ovalbumin (OVA) and the adjuvant unmethylated cytosine-phosphate-guanine (CpG) by electrostatic binding. The positively charged PEI could be beneficial to augment the PEI/CpG/OVA nanovaccine uptake in dendritic cells (DCs) and facilitate the endosomal escape of the nanovaccine for antigen delivering into the cytoplasm. The nanovaccine showed significant stimulation on DCs' maturation in vitro, and it was further applied for in vivo anti-tumor immunotherapy. To enhance the tumor infiltration of the nanovaccine-generated tumor-specific T cells, hyaluronidase (HAase) was employed to increase the permeability of the tumor tissues by breaking down the hyaluronan (HA) in the extracellular matrix (ECM) of tumors. Highly enhanced in vivo anti-tumor therapeutic efficiency was achieved by combining the PEI/CpG/OVA nanovaccine with HAase, which was attributed to the increased quantity of OVA-specific T cells in tumor tissues. The combination of nanovaccine with HAase has offered a simple and efficient strategy for inducing powerful anti-tumor effect in cancer immunotherapy.

Dendritic Mesoporous Silica Nanoparticles for pH-Stimuli-Responsive Drug Delivery of TNF-Alpha

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic immune stimulatory cytokine and natural endotoxin that can induce necrosis and regression in solid tumors. However, systemic administration of TNF-α is not feasible due to its short half-life and acute toxicity, preventing its widespread use in cancer treatment. Dendritic mesoporous silica nanoparticles (DMSN) are used coated with a pH-responsive block copolymer gate system combining charged hyperbranched polyethylenimine and nonionic hydrophilic polyethylenglycol to encapsulate TNF-α and deliver it into various cancer cell lines and dendritic cells. Half-maximal effective concentration (EC₅₀ ) for loaded TNF-α is reduced by more than two orders of magnitude. Particle stability and premature cargo release are assessed with enzyme-linked immunosorbent assay. TNF-α-loaded particles are stable for up to 5 d in medium. Tumor cells are grown in vitro as 3D fluorescent ubiquitination-based cell cycle indicator spheroids that mimic in vivo tumor architecture and microenvironment, allowing real-time cell cycle imaging. DMSN penetrate these spheroids, release TNF-α from its pores, preferentially affect cells in S/G2/M phase, and induce cell death in a time- and dose-dependent manner. In conclusion, DMSN encapsulation is demonstrated, which is a promising approach to enhance delivery and efficacy of antitumor drugs, while minimizing adverse side effects.

The Process and Regulatory Components of Inflammation in Brain Oncogenesis

Central nervous system tumors comprising the primary cancers and brain metastases remain the most lethal neoplasms and challenging to treat. Substantial evidence points to a paramount role for inflammation in the pathology leading to gliomagenesis, malignant progression and tumor aggressiveness in the central nervous system (CNS) microenvironment. This review summarizes the salient contributions of oxidative stress, interleukins, tumor necrosis factor-α(TNF-α), cyclooxygenases, and transcription factors such as signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB) and the associated cross-talks to the inflammatory signaling in CNS cancers. The roles of reactive astrocytes, tumor associated microglia and macrophages, metabolic alterations, microsatellite instability, O⁶-methylguanine DNA methyltransferase (MGMT) DNA repair and epigenetic alterations mediated by the isocitrate dehydrogenase 1 (IDH1) mutations have been discussed. The inflammatory pathways with relevance to the brain cancer treatments have been highlighted.

Lipopolyplex potentiates anti-tumor immunity of mRNA-based vaccination

mRNA-based vaccines have the benefit of triggering robust anti-cancer immunity without the potential danger of genome integration from DNA vaccines or the limitation of antigen selection from peptide vaccines. Yet, a conventional mRNA vaccine comprising of condensed mRNA molecules in a positively charged protein core structure is not effectively internalized by the antigen-presenting cells. It cannot offer sufficient protection for mRNA molecules from degradation by plasma and tissue enzymes either. Here, we have developed a lipopolyplex mRNA vaccine that consists of a poly-(β-amino ester) polymer mRNA core encapsulated into a 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine/1,2-dioleoyl-sn-glycero-3-phosphatidyl-ethanolamine/1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000 (EDOPC/DOPE/DSPE-PEG) lipid shell. This core-shell structured mRNA vaccine enters dendritic cells through macropinocytosis. It displayed intrinsic adjuvant activity by potently stimulating interferon-β and interleukin-12 expression in dendritic cells through Toll-like receptor 7/8 signaling. Dendritic cells treated with the mRNA vaccine displayed enhanced antigen presentation capability. Mice bearing lung metastatic B16-OVA tumors expressing the ovalbumin antigen were treated with the lipopolyplex mRNA, and over 90% reduction of tumor nodules was observed. Collectively, this core-shell structure offers a promising platform for mRNA vaccine development.

Propolis modulates miRNAs involved in TLR-4 pathway, NF-κB activation, cytokine production and in the bactericidal activity of human dendritic cells

Objectives

Dendritic cells (DCs) are antigen-presenting cells, essential for recognition and presentation of pathogens to T cells. Propolis, a resinous material produced by bees from various plants, exhibits numerous biological properties, highlighting its immunomodulatory action. Here, we assayed the effects of propolis on the maturation and function of human DCs.

Methods

DCs were generated from human monocytes and incubated with propolis and LPS. NF-κB and cytokines production were determined by ELISA. microRNA's expression was analysed by RT-qPCR and cell markers detection by flow cytometry. Colony-forming units were obtained to assess the bactericidal activity of propolis-treated DCs.

Key findings

Propolis activated DCs in the presence of LPS, inducing NF-kB, TNF-α, IL-6 and IL-10 production. The inhibition of hsa-miR-148a and hsa-miR-148b abolished the inhibitory effects on HLA-DR and pro-inflammatory cytokines. The increased expression of hsa-miR-155 may be correlated to the increase in TLR-4 and CD86 expression, maintaining LPS-induced expression of HLA-DR and CD40. Such parameters may be involved in the increased bactericidal activity of DCs against Streptococcus mutans.

Conclusion

Propolis modulated the maturation and function of DCs and may be useful in the initial steps of the immune response, providing a novel approach to the development of DC-based strategies and for the discovery of new immunomodulators.

The immunotoxicity of aluminum trichloride on rat peritoneal macrophages via β2-adrenoceptors/cAMP pathway acted by norepinephrine

The previous research found that norepinephrine (NE) enhanced the immunotoxicity of aluminum trichloride (AlCl3) on rat peritoneal macrophages in vitro through activating the β2-adrenoceptors (β2-AR)/cAMP pathway. On that basis, the experiment in vivo was conducted in this experiment. Eighty Wistar rats were orally exposed to 0 (control group); 0.4 mg/mL (low-dose group); 0.8 mg/mL (mid-dose group) and 1.6 mg/mL (high-dose group) AlCl3 for 120 days, respectively. Aluminum (Al), NE, macrophage migration inhibitory factor (MIF) and tumor necrosis factor-α (TNF-α) contents in serum, cAMP content, β2-AR density, mRNA expressions of TNF-α, MIF and β2-AR in rat peritoneal macrophages were examined. These results showed that AlCl3 increased serum Al and NE contents, peritoneal macrophages cAMP content, the density and mRNA expression of the β2-AR, and decreased serum MIF and TNF-α contents, peritoneal macrophages mRNA expressions of MIF and TNF-α. Serum NE content was negatively correlated with serum TNF-α and MIF contents and peritoneal macrophages mRNA expressions of TNF-α and MIF, but positively correlated with cAMP content, density of β2-AR and mRNA expression of β2-AR of peritoneal macrophages. It indicated that AlCl3 suppresses peritoneal macrophages function of rats through β2-AR/cAMP pathway acted by NE.

Treatment with cyclophosphamide supported by various dendritic cell-based vaccines induces diversification in CD4⁺ T cell response against MC38 colon carcinoma

The present study shows that an application of cyclophosphamide (CY) supported by dendritic cell (DC)-based vaccines affected differentiation of the activity of CD4⁺ T cell subpopulations accompanied by an alteration in CD8⁺ cell number. Vaccines were composed of bone marrow-derived DCs activated with tumor cell lysate (BM-DC/TAg^TNF-α) and/or genetically modified DCs of JAWS II line (JAWS II/ Neo or JAWS II/IL-2 cells). Compared to untreated or CY-treated mice, the combined treatment of MC38 colon carcinoma-bearing mice resulted in significant tumor growth inhibition associated with an increase in influx of CD4⁺ and CD8⁺ T cells into tumor tissue. Whereas, the division of these cell population in spleen was not observed. Depending on the nature of DC-based vaccines and number of their applications, both tumor infiltrating cells and spleen cells were able to produce various amount of IFN-γ, IL-4 and IL-10 after mitogenic ex vivo stimulation. The administration of CY followed by BM-DC/TAg^TNF-α and genetically modified JAWS II cells, increased the percentage of CD4⁺T-bet⁺ and CD4⁺GATA3⁺ cells and decreased the percentage of CD4⁺RORγt⁺ and CD4⁺FoxP3⁺ lymphocytes. However, the most intensive response against tumor was noted after the ternary treatment with CY + BM-DC/TAg^TNF-α + JAWS II/IL-2 cells. Thus, the administration of various DC-based vaccines was responsible for generation of the diversified antitumor response. These findings demonstrate that the determination of the size of particular CD4⁺ T cell subpopulations may become a prognostic factor and be the basis for future development of anticancer therapy.

Cholesteryl Pullulan Encapsulated TNF-α Nanoparticles Are an Effective Mucosal Vaccine Adjuvant against Influenza Virus

We encapsulated tumor necrosis factor-α (TNF-α), a major proinflammatory cytokine, into cholesteryl pullulan (CHP) to prepare TNF/CHP nanoparticles. In this report, we describe the immune-enhancing capability of the nanoparticles to act as a vaccine adjuvant. TNF/CHP nanoparticles showed excellent storage stability and enhanced host immune responses to external immunogens. The nanoparticles were effective via the nasal route of administration for inducing systemic IgG₁ as well as mucosal IgA. We applied the nanoparticles in a model experimental influenza virus infection to investigate their adjuvant ability. TNF/CHP nanoparticles combined with a conventional split vaccine protected mice via nasal administration against a lethal challenge of A/PR/8/34 (H1N1) influenza virus. Mechanistic studies showed that the nanoparticles enhanced antigen uptake by dendritic cells (DCs) and moderately induced the expression of inflammation-related genes in nasopharynx lymphoid tissue (NALT), leading to the activation of both B and T cells. Preliminary safety study revealed no severe toxicity to TNF/CHP nanoparticles. Slight-to-moderate influences in nasal mucosa were observed only in the repeated administration and they seemed to be reversible. Our data show that TNF/CHP nanoparticles effectively enhance both humoral and cellular immunity and could be a potential adjuvant for vaccines against infectious diseases, especially in the mucosa.

Identification of Toxoplasma gondii protein fractions induce immune response against melanoma in mice

Dendritic cells (DCs) play a crucial role in the initiation of adaptive immune responses against tumor cells. We recently found that protein components of Toxoplasma gondii (T. gondii) could mature DCs efficiently. Therefore, in this study, we aimed to find the most effective protein components of T. gondii which are able to mature DCs and consequently instruct immune responses in tumor-bearing mice. Soluble tachyzoite antigens (STAgs) were fractionated by ammonium sulfate precipitation and subsequently by anion-exchange HPLC. Immature DCs (iDCs) were treated by these protein fractions and were monitored for IL-12p70 and IL-10 production. Moreover, the capacity of mature DCs (mDCs) to induce lymphocyte proliferation was investigated. Ultimately, we analyzed the ability of mDCs in instructing immune responses in tumor-bearing mice. We found that ammonium sulfate fraction one (A1) matured-DCs produced higher IL-12 level and IL-12/IL-10 ratio; therefore, this fraction was selected for further fractionation by anion-exchange HPLC. The results showed that anion-exchange HPLC fraction 14 (C14) matured-DCs secrete higher levels of IL-12p70 and IL-12p70/IL-10 ratio. Survival of the mice matured by A1 fraction increased significantly compared to other groups. Moreover, SDS-PAGE electrophoresis showed that different obtained fractions have distinct proteins based on their size. These results demonstrate that two protein fractions of T. gondii are able to mature DCs more efficient.

Differential T-helper cell polarization after allergen-specific stimulation of autologous dendritic cells in polysensitized allergic patients

Background

Dendritic cells (DCs) play an important role in the induction and regulation of adaptive immune responses by polarizing T-helper (Th) cells. In allergic disease this response is dominated by Th2 cells. It is still unclear whether the activation of Th cells by DCs in atopic individuals is allergen specific.

Methods

Monocyte-derived DCs (MoDCs) obtained from polysensitized patients were stimulated with purified Bet v 1, Phl p 5 and Act d 10, and the surface marker expression was analysed. Proliferation and cytokine profiles of autologous naïve CD4+ T cells co-cultured with allergen-pulsed MoDCs were assessed.

Results

The addition of either Bet v 1 or Phl p 5 did not further increase the expression of surface markers from matured MoDCs in all study groups. In co-cultures, autologous naïve CD4+ T cells proliferated when DCs obtained from individuals allergic to birch and grass pollen were stimulated with Bet v 1 and Phl p 5, respectively. In the co-culture supernatants, significantly increased levels of IL-5 and IL-13 were detected. This effect correlated with the sensitization background and was absent when applying an unspecific allergen, Act d 10. The levels of IL-10 in supernatants of MoDCs and the levels of IL-10 and IFN-γ in supernatants of T cells remained unchanged upon stimulation with allergens.

Conclusions

In this study we observed that allergen-specific stimulation of MoDCs induces T-cell proliferation and upregulation of Th2-type cytokines. Interestingly, this Th2 polarization was only observed in cells stimulated with the allergen to which the patients were sensitized.

Dendritic cell maturation and survival are differentially regulated by TNFR1 and TNFR2

The capacity of dendritic cells (DC) to regulate adaptive immunity is controlled by their maturation state and lifespan. Although TNF is a well-known maturation and survival factor for DC, the role of the two TNFR, TNFR1 and TNFR2, in mediating these effects is poorly understood. By using unique TNF variants that selectively signal through TNFR1 and/or TNFR2, we demonstrate differential functions of TNFR in human monocyte-derived and blood CD1c(+) DC. Activation of TNFR1, but not TNFR2, efficiently induced DC maturation, as defined by enhanced expression of cell surface maturation markers (CD83, CD86, and HLA-DR) as well as enhanced T cell stimulatory capacity. In contrast, both TNFR1 and TNFR2 significantly protected DC against cell death, indicating that innate signals can promote DC survival in the absence of DC maturation. We further show differential activation of NF-κB signaling pathways by the TNFR: TNFR1 activated both the p65 and p52 pathways, whereas TNFR2 triggered p52, but not p65, activation. Accordingly, the p65 NF-κB pathway only played a role in the prosurvival effect of TNFR1. However, cell death protection through both TNFR was mediated through the Bcl-2/Bcl-xL pathway. Taken together, our data show that TNFR1, but not TNFR2, signaling induces DC maturation, whereas DC survival can be mediated independently through both TNFR. These data indicate differential but partly overlapping responses through TNFR1 and TNFR2 in both inflammatory and conventional DC, and they demonstrate that DC maturation and DC survival can be regulated through independent signaling pathways.

The stimulatory effect of different CpG oligonucleotides on the maturation of chicken bone marrow-derived dendritic cells

CpG oligonucleotide (CpG-ODN) can exert an immunostimulatory effect on different types of immune cells such as dendritic cells (DC). The immunostimulatory activity of CpG-ODN is closely related to its nucleotide sequence and structural characteristics. In this study, we aimed at evaluating the stimulatory effects of different CpG-ODN on the maturation of chicken bone marrow-derived DC (BM-DC) in vitro. First, 4 CpG-ODN were designed. Then chicken bone marrow cells were extracted from tibia and femur and cultured in the RPMI 1640 medium with recombinant chicken granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4. After culture for 6 d, the cells were stimulated by different CpG-ODN or lipopolysaccharide for 24 h. Finally, the effects of different CpG-ODN on the maturation of chicken BM-DC were investigated by morphologic, phenotypic, and functional assays. The results showed that the cultured cells could display the typical DC morphology, and the CpG-ODN could efficiently stimulate the BM-DC to show the mature morphologic characteristics and upregulate the expression of cluster of differentiation (CD) 40 and CD86 molecules. In addition, after stimulation by CpG-ODN, the BM-DC could significantly induce T-cell proliferative response (P < 0.01). Among all the sequences, the stimulatory effect of CpG-ODN F3 with an addition of poly-guanosine strings at the 3' end was the best on the chicken BM-DC. In conclusion, this is the first report to demonstrate that different CpG-ODN have distinct stimulatory effects on the maturation of chicken BM-DC and CpG-ODN F3 with the best stimulatory effect can be a potent stimulant for the maturation of chicken BM-DC.

Tumor necrosis factor is dispensable for the success of immunogenic anticancer chemotherapy

The antineoplastic effects of anthracyclines have been shown to rely, at least in part, on a local immune response that involves dendritic cells (DCs) and several distinct subsets of T lymphocytes. Here, we show that the administration of anthracyclines to mice bearing established neoplasms stimulates the intratumoral secretion of tumor necrosis factor α (TNFα). However, blocking the TNFα/TNF receptor (TNFR) system by three different strategies—namely, (1) neutralizing antibodies, (2) etanercept, a recombinant protein in which TNFR is fused to the constant domain of an IgG₁ molecule, and (3) gene knockout—failed to negatively affect the therapeutic efficacy of anthracyclines in three distinct tumor models. In particular, TNFα-blocking strategies did not influence the antineoplastic effects of doxorubicin (a prototypic anthracycline) against MCA205 fibrosarcomas growing in C57BL/6 mice, F244 sarcomas developing in 129/Sv hosts and H2N100 mammary carcinomas arising in BALB/c mice. These findings imply that, in contrast to other cytokines (such as interleukin-1β, interleukin-17 and interferon γ), TNFα is not required for anthracyclines to elicit therapeutic anticancer immune responses.

Cyclooxygenase-2 enzyme induces the expression of the α-2,3-sialyltransferase-3 (ST3Gal-I) in breast cancer

Aberrant glycosylation is a common feature of malignant change. Changes in mucin-type O-linked glycosylation in breast cancer can result in the expression of truncated core 1-based sialylated glycans rather than the core 2-based glycans observed in normal mammary epithelium cells. This has been shown, in part, to be due to changes in the expression of glycosyltransferases, including the up-regulation of some sialyltransferases. Using the breast cancer cell line T47D, we have shown that PGE2, one of the final products of the cyclooxygenase-2 (COX-2) pathway, can induce the mRNA expression of the sialyltransferase α-2,3-sialyltransferase-3 (ST3Gal-I), resulting in increased sialyltransferase activity, demonstrated by a reduction in PNA lectin staining. Induction of COX-2 in the MDA-MB-231 breast cancer cell line also results in the increased expression of ST3Gal-I, leading to increased sialylation of the substrate of ST3Gal-I, core 1 Galβ1,3GalNAc. This effect on sialylation could be reversed by the selective COX-2 inhibitor celecoxib. The use of siRNA to knock down COX-2 and overexpression of COX-2 in MDA-MD-231 cells confirmed the involvement of COX-2 in the up-regulation of ST3Gal-I. Moreover, analysis of the expression of ST3Gal-I and COX-2 by 74 primary breast cancers showed a significant correlation between the two enzymes. COX-2 expression has been associated with a number of tumors, including breast cancer, where its expression is associated with poor prognoses. Thus, these results suggest the intriguing possibility that some of the malignant characteristics associated with COX-2 expression may be via the influence that COX-2 exerts on the glycosylation of tumor cells.

Immunostimulatory and anti-neoplasm effects of a novel palindrome CpG oligodeoxynucleotide in mice

AIM

DNAs containing unmethylated CpG motifs can stimulate innate and adaptive immunity. The aim of this study was to investigate the immunostimulatory and anti-neoplasm effects of a novel CpG oligodeoxynucleotide, ODN10, in tumor-bearing mice.

METHODS

B16 melanoma-bearing C57BL/6 mice were administered ip or sc with ODN10 or conventional CpG ODN1826 on the indicated days post inoculation. The animal survival rate and the inhibitory effect on tumor growth were observed in vivo. B and T lymphocyte proliferation, natural killing cell cytotoxicity and the phagocytic ability of peritoneal macrophages from the animals were determined using [(3)H]-thymidine incorporation assay, 4-h (51)Cr release assay and neutral red chromometry method, respectively. The serum levels of IL-12, IL-4 and IgE were quantified using ELISA assays. Histological examination of tumor tissues was performed after HE staining, and the expression of PCNA, CD63, and CD80 in tumor tissues was analyzed with immunohistochemistry.

RESULTS

ODN10 (1, 5 and 25 mg/kg) significantly inhibited the growth and metastasis of the tumor, and significantly prolonged the survival of tumor-bearing mice, as compared with ODN1826. The immune status was suppressed in tumor-bearing mice. Both ODN10 and ODN1826 significantly reversed the suppressed immunoactivities in tumor-bearing mice, which included promoting B and T lymphocyte proliferation, enhancing NK cell and peritoneal macrophage activities, inducing IL-12 secretion and inhibiting IL-4 and IgE secretion. Further, CpG ODNs decreased PCNA and CD63 expression while induced expression of CD80. ODN10 presented more potent activity, and displayed the most prominent immunostimulatory potential.

CONCLUSION

ODN10 produces prominent immunomodulatory effects on cellular immunity in tumor-bearing mice, which might help reverse the established Th2-type responses to the Th1-type responses, thus may be used as a potent anti-tumor immunotherapy agent or adjuvant.

Dendritic cell-derived tumor necrosis factor α modifies airway epithelial cell responses

Mucosal dendritic cells (DC) are intimately associated with the airway epithelium and thus are ideally situated to be first responders to pathogens. We hypothesize that DC drive innate immune responses through early release of tumor necrosis factor (TNF) α, which drives airway epithelial cell responses. In a mouse model, TNFα release was significantly increased following a single exposure to German cockroach (GC) frass, an event independent of neutrophil recruitment into the airways. While lung epithelial cells and alveolar macrophages failed to release TNFα following GC frass exposure, bone marrow-derived DC (BMDC) produced substantial amounts of TNFα suggesting their importance as early responding cells. This was confirmed by flow cytometry of pulmonary myeloid DC. Addition of GC frass-pulsed BMDC or conditioned media from GC frass-pulsed BMDC to primary mouse tracheal epithelial cells (MTEC) or MLE-15 cells induced chemokine (C-C) motif ligand (CCL) 20 and granulocyte macrophage (GM) colony-stimulating factor (CSF), both of which are important for DC recruitment, survival and differentiation. Importantly, DC do not produce CCL20 or GM-CSF following allergen exposure. Blocking TNFα receptor 1 (TNFR1) completely abolished chemokine production, suggesting that BMDC-derived TNFα induced airway epithelial cell activation and enhancement of the innate immune response. Lastly, blocking TNFR1 in vivo resulted in significantly decreased CCL20 and GM-CSF production in the lungs of mice. Together, our data strongly suggest that DC-derived TNFα plays a crucial role in the initiation of innate immune responses through the modification of airway epithelial cell responses.

TNF receptor 1 mediates dendritic cell maturation and CD8 T cell response through two distinct mechanisms

TNF-α and its two receptors (TNFR1 and 2) are known to stimulate dendritic cell (DC) maturation and T cell response. However, the specific receptor and mechanisms involved in vivo are still controversial. In this study, we show that in response to an attenuated mouse hepatitis virus infection, DCs fail to mobilize and up-regulate CD40, CD80, CD86, and MHC class I in TNFR1(-/-) mice as compared with the wild-type and TNFR2(-/-) mice. Correspondingly, virus-specific CD8 T cell response was dramatically diminished in TNFR1(-/-) mice. Adoptive transfer of TNFR1-expressing DCs into TNFR1(-/-) mice rescues CD8 T cell response. Interestingly, adoptive transfer of TNFR1-expressing naive T cells also restores DC mobilization and maturation and endogenous CD8 T cell response. These results show that TNFR1, not TNFR2, mediates TNF-α stimulation of DC maturation and T cell response to mouse hepatitis virus in vivo. They also suggest two mechanisms by which TNFR1 mediates TNF-α-driven DC maturation, as follows: a direct effect through TNFR1 expressed on immature DCs and an indirect effect through TNFR1 expressed on naive T cells.

STAT3 Knockdown in B16 Melanoma by siRNA Lipopolyplexes Induces Bystander Immune Response In Vitro and In Vivo

Persistent activation of STAT3 plays a major role in cancer progression and immune escape. Therefore, targeting STAT3 in tumors is essential to enhance/reactivate antitumor immune response. In our previous studies, we demonstrated the efficacy of stearic acid-modified polyethylenimine (PEI-StA) in promoting small interfering RNA (siRNA) silencing of STAT3 in B16.F10 melanoma in vitro and in vivo. In the current study, we examine the immunologic impact of this intervention. Toward this goal, the infiltration and activation of lymphocytes and dendritic cells (DCs) in the tumor mass were assessed using flow cytometry. Moreover, the levels of IFN-γ, IL-12, and TNF-α in homogenized tumor supernatants were determined. Moreover, mixed lymphocytes reaction using splenocytes of tumor-bearing mice was used to assess DC functionality on siRNA/lipopolyplexes intervention. Our results demonstrated up to an approximately fivefold induction in the infiltration of CD3(+) cells in tumor mass on STAT3 knockdown with high levels of CD4(+), CD8(+), and NKT cells. Consistently, DC infiltration in tumor milieu increased up to approximately fourfold. Those DCs were activated, in an otherwise suppressive microenvironment, as evidenced by a high expression of costimulatory molecules CD86 and CD40. ELISA analysis revealed a significant increase in IFN-γ, IL-12, and TNF-α. Moreover, mixed lymphocytes reaction demonstrated alloreactivity of these DCs as assessed by high T-cell proliferation and IL-2 production. Our results suggest a bystander immune response after local STAT3 silencing by siRNA. This strategy could be beneficial as an adjuvant therapy along with current cancer vaccine formulations.

Mechanical injury polarizes skin dendritic cells to elicit a T(H)2 response by inducing cutaneous thymic stromal lymphopoietin expression

BACKGROUND

Atopic dermatitis is characterized by scratching and by T(H)2-dominated immune response to cutaneously introduced antigens. Antigen application to skin mechanically injured by tape stripping results in T(H)2-dominated skin inflammation.

OBJECTIVE

To examine the effect of tape stripping on the capacity of skin dendritic cells (DCs) to polarize T cells toward a T(H)2 phenotype.

METHODS

CD11c(+) DCs were isolated from skin of BALB/c or C57BL/6 mice. Fluorescein isothiocyanate (FITC)(+) and FITC(-) DCs were isolated from draining lymph nodes (DLNs) 24 hours after painting the skin with FITC. DCs were assessed for their ability to induce cytokine secretion by ovalbumin-stimulated naive CD4(+) T cells from T cell receptor-ovalbumin transgenic DO11.10 mice. Cytokine mRNA levels were examined by quantitative PCR.

RESULTS

Dendritic cells isolated from the skin of wild-type, but not thymic stromal lymphopoietin (TSLP) receptor(-/-) or IL-10(-/-), mice 6 hours after tape stripping elicited significantly more IL-4 and IL-13 and significantly less IFN-γ production by CD4(+) cells than DCs isolated from unmanipulated skin, and expressed significantly more mRNA for the T(H)2 skewing molecules IL-10, Jagged1, and Jagged2, but significantly less mRNA for the T(H)1 skewing cytokine IL-12. CD11c(+)FITC(+) cells isolated from DLNs of shaved and tape stripped skin of wild-type, but not TSLP receptor(-/-) or IL-10(-/-), mice polarized T cells significantly more toward T(H)2 and expressed significantly more IL-10, Jagged1, and Jagged2 mRNA than CD11c(+)FITC(+) cells isolated from DLNs of shaved skin. Tape stripping significantly increased TSLP levels in the skin, and TSLP was shown to play an essential role in the T(H)2 polarization of skin DCs by tape stripping.

CONCLUSIONS

Tape stripping upregulates TSLP levels in the skin, which polarizes skin DCs to elicit a T(H)2 response via the induction of IL-10.

Tumor necrosis factor gene-engineered J558 tumor cell-released exosomes stimulate tumor antigen P1A-specific CD8+ CTL responses and antitumor immunity

Exosomes (EXOs) derived from tumor cells have been used to stimulate antitumor immune responses. It has been demonstrated that EXO released by tumor cells engineered to express cytokines are of enhanced stimulatory effect on CD8(+) cytotoxic T-lymphocyte (CTL) responses and antitumor immunity. J558 is a mouse myeloma cell line expressing tumor antigen P1A. In this study, we purified EXO(TNF-a), EXO(IL-2), and EXO(IFN-gamma) released by three cytokine-gene (TNF-alpha, IL-2 and IFN-gamma)-engineered J558 (J558(TNF-a), J558(IL-2) and J558(IFN-gamma)) tumor cell lines from their culture supernatants, respectively, by differential ultracentrifugation. These EXOs showed a "saucer" or round shape with a diameter between 50 and 90 nm by electron microscopy and contained EXO-associated proteins, such as LAMP-1 and AIP1, but not lysate-associated protein galectin, by Western blot analysis. EXO displayed expression of molecules (H-2K(d), CD54, and P1A) similarly to, but to a lesser extent to, J558 tumor cells. We then compared the stimulatory effect of these EXOs on P1A-specific CD8(+) CTL responses and antitumor immunity 6 days subsequent to intravenous (i.v.) EXO immunization (30 microg/each BALB/c mouse). We demonstrated that EXO(TNF-alpha) immunization was able to induce more efficient P1A-specific CD8(+) T-cell response accounting for 0.62% of the total CD8(+) T-cell population, using PE-H-2K(d)/P1A peptide and FITC-CD8 staining by flow cytometric analysis then EXO(IL-2) (0.31%) and EXO(IFN-gamma) (0.22%) immunization (P < 0.05), respectively, at day 6 after immunization. EXO(IL-2) and EXO(IFN-gamma) vaccine (i.v. 30 microg/each mouse) only protected 3 of 8 (38%) and 2 of 8 (25%) mice from tumor growth after subcutaneous (s.c.) challenging of immunized mice with J558 tumor cells (0.5 x 10(6) cells/each mouse), whereas EXO(TNF-alpha) immunization protected all 8 of 8 (100%) mice from tumor growth (P < 0.05). Taken together, we demonstrate that EXO(TNF-a) released by engineered J558(TNF-a) tumor cells more efficiently stimulate tumor antigen P1A-specific CD8(+) CTL responses and antitumor immunity than EXO(IL-2) and EXO(IFN-gamma) released by engineered J558(IL-2) and J558(IFN-gamma) tumor cells. Therefore, TNF-alpha-expressing tumor cell-released EXO may represent a more effective EXO-based vaccine in the induction of antitumor immunity.

Effect of double-stranded DNA on maturation of dendritic cells in vitro

A preparation of human genomic fragmented double-stranded DNA (dsDNA) was used as maturation stimulus in cultures of human dendritic cells (DCs) generated in compliance with the interferon protocol. Culturing of the DCs in medium with 5μg/ml of the DNA preparation was associated with a decrease in the relative proportion of CD14 + cells and an increase in that of CD83 + cells. These changes are markers of DC maturation. The efficiency with which the DNA preparation was able to elicit DC maturation was commensurate with that of lypopolysaccharide from bacterial cell, the standard inducer of DC maturation. Generated ex vivo, matured in the presence of the human DNA preparation, pulsed with tumor antigens mouse DCs were used as a vaccine in biological tests for its antitumor activity. The experimental results demonstrate that reinfusion of mature pulsed with tumor antigens DCs cause a statistically significant suppression of tumor graft growth.