Polarization of naive T cells into Th1 or Th2 by distinct cytokine-driven murine dendritic cell populations: implications for immunotherapy

Atopic dermatitis and IgE-mediated food allergy: Common biologic targets for therapy and prevention

OBJECTIVE

To highlight common mechanistic targets for the treatment of atopic dermatitis (AD) and IgE-mediated food allergy (IgE-FA) with potential to be effective for both diseases and prevent atopic progression.

DATA SOURCES

Data sources were PubMed searches or National Clinical Trials (NCT)-registered clinical trials related to AD, IgE-FA, and other atopic conditions, especially focused on the pediatric population.

STUDY SELECTIONS

Human seminal studies and/or articles published in the past decade were emphasized with reference to preclinical models when relevant. NCT-registered clinical trials were filtered by inclusion of pediatric subjects younger than 18 years with special focus on children younger than 12 years as a critical period when AD and IgE-FA diseases may often be concurrent.

RESULTS

AD and IgE-FA share several pathophysiologic features, including epithelial barrier dysfunction, innate and adaptive immune abnormalities, and microbial dysbiosis, which may be critical for the clinical progression between these diseases. Revolutionary advances in targeted biologic therapies have shown the benefit of inhibiting type 2 immune responses, using dupilumab (anti-interleukin-4Rα) or omalizumab (anti-IgE), to potentially reduce symptom burden for both diseases in pediatric populations. Although the potential for biologics to promote disease remission (AD) or sustained unresponsiveness (IgE-FA) remains unclear, the refinement of biomarkers to predict infants at risk for atopic disorders provides promise for prevention through timely intervention.

CONCLUSION

AD and IgE-FA exhibit common features that may be leveraged to develop biologic therapeutic strategies to treat both conditions and even prevent atopic progression. Future studies should be designed with consistent age stratification in the pediatric population and standardized regimens of adjuvant oral immunotherapy or dose escalation (IgE-FA) to improve cross-study interpretation.

Anti-allergic function of the cell wall (DeinoWall) from Deinococcus radiodurans

Deinococcus radiodurans is an extremophile, well known to be extremely resistant to external stresses due to its unique physiological system and structure of cellular components. Although the proportion of D. radiodurans has been reported to be negatively correlated with atopic dermatitis, the exact function of D. radiodurans in allergic diseases and its precise mechanisms have not been studied. In the present study, we hypothesize that D. radiodurans or its cellular constituents play a critical role in the skin to prevent allergic inflammatory responses by modulating immunity. Heat-killed D. radiodurans inhibited the production of Th2 cytokines, such as IL-4 and IL-5, induced by ovalbumin (OVA) stimulation in splenocytes from OVA-sensitized mice. Among the cellular constituents of D. radiodurans, such as cell wall (DeinoWall), cell membrane (DeinoMem), and exopolysaccharide (DeinoPol), only DeinoWall inhibited the production of Th2 cytokines and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD), a Th2-predominant allergic disease in mice. Moreover, serum IgE levels and infiltration of mast cells into skin lesions, the markers of Th2 response induced by DNCB application, were significantly inhibited by treatment with DeinoWall. Remarkably, DeinoWall induced the maturation of bone marrow-derived dendritic cells (BMDCs) that promote Th1-biased immunity, which might balance Th1/Th2 and regulate allergic inflammatory responses. Collectively, these results suggest that DeinoWall acts as a major cellular constituent in the negative regulation of allergic inflammatory responses by D. radiodurans and might be a viable candidate for the treatment of allergic diseases.

The association between diabetes and obesity with Dengue infections

Dengue, an arboviral disease is a global threat to public health as the number of Dengue cases increases through the decades and this trend is predicted to continue. Non-communicable diseases such as diabetes and obesity are also on an upward trend. Moreover, past clinical studies have shown comorbidities worsen the clinical manifestation of especially Severe Dengue. However, discussion regarding the underlying mechanisms regarding the association between these comorbidities and dengue are lacking. The hallmark of Severe Dengue is plasma leakage which is due to several factors including presence of pro-inflammatory cytokines and dysregulation of endothelial barrier protein expression. The key factors of diabetes affecting endothelial functions are Th1 skewed responses and junctional-related proteins expression. Additionally, obesity alters the lipid metabolism and immune response causing increased viral replication and inflammation. The similarity between diabetes and obesity individuals is in having chronic inflammation resulting in endothelial dysfunction. This review outlines the roles of diabetes and obesity in severe dengue and gives some insights into the plausible mechanisms of comorbidities in Severe Dengue.

CD47 blockade enhances therapeutic efficacy of cisplatin against lung carcinoma in a murine model

Cisplatin (CDDP) is the first generation of platinum-based drug and is widely used to treat many cancers due to its potency. The present study aims to explore the effects of CDDP on lung carcinoma and its relationship with macrophage phagocytosis. In in vitro study, murine and human lung cancer cell lines were applied and treated with CDDP, CD47 antibody (aCD47), or CDDP plus aCD47. In in vivo study, a tumor xenograft animal model was treated with CDDP, aCD47, or CDDP plus aCD47. Real-time PCR was applied to determine the mRNA expressions. Enzyme-linked immunosorbent assay (ELISA), Western blotting, and Immunofluorescent staining were applied to determine the protein expressions. Flow cytometry was applied to analyze cell apoptosis, phagocytosis, and specific cell populations. CDDP enhanced the expressions of CD47 in lung cancer cells. Interestingly, the blockage of CD47 enhanced the macrophages' phagocytic activity on the CDDP-treated tumor cells. The treatment of CDDP and aCD47 exhibited anti-tumor effects and prolonged the LLC tumor-bearing mice survival time. Mechanistic studies revealed that the treatment of CDDP and aCD47 regulated the phagocytic activity of macrophage, percentage of CD8+ T cells, and cytokines (tumor growth factor (TGF)-β, interleukin (IL)12p70, and interferon (IFN)-γ) in the tumor-bearing model. CD47 blockade enhanced therapeutic efficacy of cisplatin against lung carcinoma in vivo and in vitro.

IFP35 family proteins promote neuroinflammation and multiple sclerosis

Excessive activation of T cells and microglia represents a hallmark of the pathogenesis of human multiple sclerosis (MS). However, the regulatory molecules overactivating these immune cells remain to be identified. Previously, we reported that extracellular IFP35 family proteins, including IFP35 and NMI, activated macrophages as proinflammatory molecules in the periphery. Here, we investigated their functions in the process of neuroinflammation both in the central nervous system (CNS) and the periphery. Our analysis of clinical transcriptomic data showed that expression of IFP35 family proteins was up-regulated in patients with MS. Additional in vitro studies demonstrated that IFP35 and NMI were released by multiple cells. IFP35 and NMI subsequently triggered nuclear factor kappa B-dependent activation of microglia via the TLR4 pathway. Importantly, we showed that both IFP35 and NMI activated dendritic cells and promoted naïve T cell differentiation into Th1 and Th17 cells. Nmi-/- , Ifp35-/- , or administration of neutralizing antibodies against IFP35 alleviated the immune cells' infiltration and demyelination in the CNS, thus reducing the severity of experimental autoimmune encephalomyelitis. Together, our findings reveal a hitherto unknown mechanism by which IFP35 family proteins facilitate overactivation of both T cells and microglia and propose avenues to study the pathogenesis of MS.

Mucosal Vaccination Primes NK Cell-Dependent Development of CD8+ T Cells Against Pulmonary Brucella Infection

Past studies with the live, double-mutant B. abortus (znBAZ) strain resulted in nearly complete protection of mice against pulmonary challenge with wild-type (wt) Brucella via a dominant CD8+ T cell response. To understand the contribution innate immune cells in priming CD8+ T cell responses, mice were nasally dosed with wt B. abortus, smooth vaccine strain 19 (S19), or znBAZ, and examined for innate immune cell activation. Flow cytometric analysis revealed that znBAZ, but not wt B. abortus nor S19 infection, induces up to a 5-fold increase in the frequency of IFN-γ-producing NK cells in mouse lungs. These NK cells express increased CXCR3 and Ki67, indicating their recruitment and proliferation subsequent to znBAZ infection. Their activation status was augmented noted by the increased NKp46 and granzyme B, but decreased NKG2A expression. Further analysis demonstrated that both lung caspase-1+ inflammatory monocytes and monocyte-derived macrophages secrete chemokines and cytokines responsible for NK cell recruitment and activation. Moreover, neutralizing IL-18, an NK cell-activating cytokine, reduced the znBAZ-induced early NK cell response. NK cell depletion also significantly impaired lung dendritic cell (DC) activation and migration to the lower respiratory lymph nodes (LRLNs). Both lung DC activation and migration to LRLNs were significantly impaired in NK cell-depleted or IFN-γ-/- mice, particularly the CD11b+ and monocytic DC subsets. Furthermore, znBAZ vaccination significantly induced CD8+ T cells, and upon in vivo NK cell depletion, CD8+ T cells were reduced 3-fold compared to isotype-treated mice. In summary, these data show that znBAZ induces lung IFN-γ+ NK cells, which plays a critical role in influencing lung DC activation, migration, and promoting protective CD8+ T cell development.

More fuel to the fire: some patients with non-celiac self-reported wheat sensitivity exhibit adaptive immunological responses in duodenal mucosa

Background

In contrast to the well-characterized Celiac Disease (CD), the clinical scenarios encompassed by the non-celiac self-reported wheat sensitivity (NCSRWS) might be related to different antigens that trigger distinct immune-inflammatory reactions. Although an increased number of intestinal intraepithelial lymphocytes is observed at the inception of both diseases, the subsequent immunopathogenic pathways seem to be different. We aimed to describe the cytokine profile observed in the duodenal mucosa of patients with NCSRWS.

Methods

In a blind, cross-sectional study, we included duodenal biopsies from 15 consecutive untreated patients with active CD, 9 individuals with NCSRWS and 10 subjects with dyspepsia without CD and food intolerances. Immunohistochemistry and flow-cytometry were used to determine the presence of pro-inflammatory cytokine expressing monocytes and monocyte-derived dendritic cells involved in innate immune activation, cytokine-driven polarization and maintenance of Th1 and Th17/Th 22, and anti-inflammatory/profibrogenic cytokines.

Results

The percentage of cells expressing all tested cytokines in the lamina propria and the epithelium was higher in CD patients than in the control group. Cytokines that induce and maintain Th1 and Th17 polarization were higher in CD than in NCSRWS and controls, also were higher in NCSRWS compared to controls. Similar differences were detected in the expression of IL-4 and TGF-1, while IL-10-expressing cells were lower in NCSRWS patients than in controls and CD subjects.

Conclusions

NCSRWS patients exhibit components of both, innate and adaptive immune mechanisms but to a lesser extent compared to CD.

Current status and perspectives regarding the association between allergic disorders and cancer

While activation of immune system may lead to a lower risk of some diseases, it has been shown that a history of atopic allergic disorders such as asthma, hay fever, eczema, and food allergies could be related to several types of cancer. However, the evidence is not entirely conclusive. Two proposals suggest a possible mechanism for the association between allergic disorders and cancers: immune surveillance and the antigenic stimulation. The association of allergy and cancer may vary by cancer site and the type of exposure. The aim of current review was to summarize the current knowledge of the association between allergic diseases and the risk of cancers with particular emphasis on case-controls and cohort studies to estimate the cancer risk associated with allergy.

Evaluation of systemic inflammatory response and lung injury induced by Crotalus durissus cascavella venom

This study investigated the systemic inflammatory response and mechanism of pulmonary lesions induced by Crotalus durissus cascavella venom in murine in the state of Bahia. In order to investigate T helper Th1, Th2 and Th17 lymphocyte profiles, we measured interleukin (IL) -2, IL-4, IL-6, IL-10, IL-17, tumor necrosis factor (TNF) and interferon gamma (IFN-γ) levels in the peritoneal fluid and macerated lungs of mice and histopathological alterations at the specific time windows of 1h, 3h, 6h, 12h, 24h and 48h after inoculation with Crotalus durissus cascavella venom. The data demonstrated an increase of acute-phase cytokines (IL-6 and TNF) in the first hours after inoculation, with a subsequent increase in IL-10 and IL-4, suggesting immune response modulation for the Th2 profile. The histopathological analysis showed significant morphological alterations, compatible with acute pulmonary lesions, with polymorphonuclear leukocyte (PMN) infiltration, intra-alveolar edema, congestion, hemorrhage and atelectasis. These findings advance our understanding of the dynamics of envenomation and contribute to improve clinical management and antiophidic therapy for individuals exposed to venom.

Bacterial Protein Toll-Like-Receptor Agonists: A Novel Perspective on Vaccine Adjuvants

Adjuvants have been used in vaccines for over a century, however, the search for safe and effective vaccine adjuvants continues. In recent decades toll-like-receptor (TLR) agonists have been investigated as potential vaccine adjuvants. In this regard, the majority of the currently investigated TLR agonists are non-protein microbial components such as lipopolysaccharides, oligonucleotides, and lipopeptides. On the other hand, a growing number of studies reveal that TLR signaling and immune responses can be activated by numerous bacterial proteins. However, their potential roles as adjuvants have been somewhat overlooked. Herein, we discuss several such bacterial proteins which exhibit adjuvant properties, including the activation of TLR signaling, antigen presenting cell maturation, pro-inflammatory cytokine production and adaptive immune response. The protein nature of these TLR agonists presents several unique features not shared by non-protein TLR agonists. These properties include the amenability for modifying the structure and function as necessary for optimal immunogenicity and minimal toxicity. Protein adjuvants can be genetically fused to protein antigens which ensure the co-delivery of adjuvant-antigen not only into the same cell but also in the same endocytic cargo, leading to more effective activation of innate and adaptive immune response.

Selenium deficiency inhibits differentiation and immune function and imbalances the Th1/Th2 of dendritic cells

Selenium (Se) deficiency inhibits immune cell differentiation, affects immune response, and leads to cellular and humoral immune dysfunction. However, the impact of Se deficiency on the differentiation and Th1/Th2 balance of dendritic cells is still unclear. In this study, we replicated a model of Se-deficient chickens by feeding the chickens with a low-Se diet (i.e., the content of Se is 0.008 mg per kg diet). On this basis, we explored the effect of Se deficiency on the differentiation of chicken dendritic cells by induction culture of peripheral blood monocyte cells. We induced chicken dendritic cells by incubating mononuclear cells with a 100 ng mL-1 recombinant chicken granulocyte-macrophage colony-stimulating factor and 20 ng mL-1 recombinant chicken IL-4 for total 7 days. The results showed that Se deficiency decreased the expression of cell-surface markers including CD11c, CD40, CD86, and MHC II. Furthermore, we analyzed the cytokine profiles using real-time quantitative PCR and ELISA. The results indicated that Se deficiency inhibited the expression of selenoproteins and changed the secretion of IL-10, IL-12p40, and IFN-γ. Additionally, Se deficiency weakened the ability of dendritic cells to stimulate the proliferation of mixed allogeneic lymphocytes. In conclusion, Se deficiency suppressed the differentiation and immune function of chicken dendritic cells by down-regulating the expression of CD11c, CD40, CD86, MHC II, and selenoproteins. The result also showed that the Th1/Th2 imbalance was induced by enhancing the secretion of Th1-type cytokine IL-12p40 and IFN-γ and reducing that of Th2-type cytokine IL-10. Our findings contribute to understanding the mechanism of Se deficiency in the differentiation and immune function of chicken dendritic cells.

IL-15 Generates IFN-γ-producing Cells Reciprocally Expressing Lymphoid-Myeloid Markers during Dendritic Cell Differentiation

Recently, interest in IL-15-differentiated cells has increased; however, the phenotypic definition of IL-15-differentiated bone marrow-derived cells (IL-15-DBMCs) is still under debate, particularly the generation of IFN-γ-producing innate cells such as premature NK (pre-mNK) cells, natural killer dendritic cells (NKDCs), interferon-producing killer dendritic cells (IKDCs), and type 1 innate lymphoid cells (ILC1s), all of which are IL-15-dependent. Here, we revisited the immunophenotypic characteristics of IFN-γ-producing IL-15-DBMCs and their functional role in the control of intracellular Mycobacterium tuberculosis (Mtb) infection. When comparing the cytokine levels between bone marrow-derived dendritic cells (BMDCs) and IL-15-DBMCs upon stimulation with various TLR agonists, only the CD11c^int population of IL-15-DBMCs produced significant levels of IFN-γ, decreased levels of MHC-II, and increased levels of B220. Neither BMDCs nor IL-15-DBMCs were found to express DX5 or NK1.1, which are representative markers for the NK cell lineage and IKDCs. When the CD11c^intB220⁺ population of IL-15-DBMCs was enriched, the Thy1.2⁺Sca-1⁺ population showed a marked increase in IFN-γ production. In addition, while depletion of the B220⁺ and Thy1.2⁺ populations of IL-15-DBMCs, but not the CD19⁺ population, inhibited IFN-γ production, enrichment of these cell populations increased IFN-γ. Ultimately, co-culture of sorted IFN-γ-producing B220⁺Thy1.2⁺ IL-15-DBMCs with Mtb-infected macrophages resulted in control of the intracellular growth of Mtb via the IFN-γ-nitric oxide axis in a donor cell number-dependent manner. Taken together, the results indicate that IFN-γ-producing IL-15-DBMCs could be redefined as CD11c^intB220⁺Thy1.2⁺Sca-1⁺ cells, which phenotypically resemble both IKDCs and ILC1s, and may have therapeutic potential for controlling infectious intracellular bacteria such as Mtb.

PDIA3 gene induces visceral hypersensitivity in rats with irritable bowel syndrome through the dendritic cell-mediated activation of T cells

This study investigated the mechanism of protein disulfide-isomerase A3 (PDIA3)-induced visceral hypersensitivity in irritable bowel syndrome (IBS). Rats were treated with saline (control), acetic acid and restraint stress (IBS model), empty vector (RNAi control) and PDIA3-RNAi vector (PDIA3-RNAi). Mesenteric lymph node DCs (MLNDCs) and splenic CD4+/CD8+ T cells were isolated for co-cultivation. Compared with control, MLNDCs co-cultured with CD4+ or CD8+ T cells showed an increased ability to promote T cell proliferation and produced more IL-4 or IL-9 secretion. Compared with the RNAi control, MLNDCs from the PDIA3 knockdown models were less effective in promoting the proliferation of CD4+/CD8+ T cells. It is concluded that PDIA3 plays an important role in the development of IBS through the DC-mediated activation of T cells, resulting in degranulation of MCs and visceral hypersensitivity.

Modulation of Female Genital Tract-Derived Dendritic Cell Migration and Activation in Response to Inflammatory Cytokines and Toll-Like Receptor Agonists

HIV transmission across the genital mucosa is a major mode of new HIV infections in women. The probability of infection may be influenced by several factors including recruitment and activation of HIV target cells, such as dendritic cells (DCs) and cytokine production, associated with genital inflammation. We evaluated the role of inflammatory cytokines and TLR signaling in migration and activation of genital tract DCs in the human cervical explant model. Hysterectomy tissues from 10 HIV-negative and 7 HIV-positive donor women were separated into ecto- and endocervical explants, and incubated with inflammatory cytokines (TNF-α, IL-1β, IL-8, MIP-1β) or agonists for TLR4 (LPS), TLR2/1 (PAM3) and TLR7/8 (R848). Migration (frequency) and activation (HLA-DR expression) of myeloid and plasmacytoid DCs and Langerhans cells were measured by flow cytometry. We observed that cytokines, LPS and PAM3 induced activation of migrating myeloid and plasmacytoid DCs. LPS induced a 3.6 fold lower levels of migration of plasmacytoid DCs from HIV-infected women compared with HIV-uninfected women (median activation indices of 2.932 vs 0.833). There was however a 4.5 fold increase in migration of Langerhans cells in HIV-infected compared with HIV-uninfected women in response to cytokines (median activation indices of 3.539 vs 0.77). Only TLR agonists induced migration and activation of DCs from endocervical explants. Hormonal contraception use was associated with an increase in activation of DC subsets in the endo and ectocervical explants. We conclude that inflammatory signals in the female genital tract induced DC migration and activation, with possible important implications for HIV susceptibility of cervical tissues.

Brucella discriminates between mouse dendritic cell subsets upon in vitro infection

Brucella is a Gram-negative bacterium responsible for brucellosis, a worldwide re-emerging zoonosis. Brucella has been shown to infect and replicate within Granulocyte macrophage colony-stimulating factor (GMCSF) in vitro grown bone marrow-derived dendritic cells (BMDC). In this cell model, Brucella can efficiently control BMDC maturation. However, it has been shown that Brucella infection in vivo induces spleen dendritic cells (DC) migration and maturation. As DCs form a complex network composed by several subpopulations, differences observed may be due to different interactions between Brucella and DC subsets. Here, we compare Brucella interaction with several in vitro BMDC models. The present study shows that Brucella is capable of replicating in all the BMDC models tested with a high infection rate at early time points in GMCSF-IL15 DCs and Flt3l DCs. GMCSF-IL15 DCs and Flt3l DCs are more activated than the other studied DC models and consequently intracellular bacteria are not efficiently targeted to the ER replicative niche. Interestingly, GMCSF-DC and GMCSF-Flt3l DC response to infection is comparable. However, the key difference between these 2 models concerns IL10 secretion by GMCSF DCs observed at 48 h post-infection. IL10 secretion can explain the weak secretion of IL12p70 and TNFα in the GMCSF-DC model and the low level of maturation observed when compared to GMCSF-IL15 DCs and Flt3l DCs. These models provide good tools to understand how Brucella induce DC maturation in vivo and may lead to new therapeutic design using DCs as cellular vaccines capable of enhancing immune response against pathogens.

Along the Axis between Type 1 and Type 2 Immunity; Principles Conserved in Evolution from Fish to Mammals

A phenomenon already discovered more than 25 years ago is the possibility of naïve helper T cells to polarize into TH1 or TH2 populations. In a simplified model, these polarizations occur at opposite ends of an "immune 1-2 axis" (i1-i2 axis) of possible conditions. Additional polarizations of helper/regulatory T cells were discovered later, such as for example TH17 and Treg phenotypes; although these polarizations are not selected by the axis-end conditions, they are affected by i1-i2 axis factors, and may retain more potential for change than the relatively stable TH1 and TH2 phenotypes. I1-i2 axis conditions are also relevant for polarizations of other types of leukocytes, such as for example macrophages. Tissue milieus with "type 1 immunity" ("i1") are biased towards cell-mediated cytotoxicity, while the term "type 2 immunity" ("i2") is used for a variety of conditions which have in common that they inhibit type 1 immunity. The immune milieus of some tissues, like the gills in fish and the uterus in pregnant mammals, probably are skewed towards type 2 immunity. An i2-skewed milieu is also created by many tumors, which allows them to escape eradication by type 1 immunity. In this review we compare a number of i1-i2 axis factors between fish and mammals, and conclude that several principles of the i1-i2 axis system seem to be ancient and shared between all classes of jawed vertebrates. Furthermore, the present study is the first to identify a canonical TH2 cytokine locus in a bony fish, namely spotted gar, in the sense that it includes RAD50 and bona fide genes of both IL-4/13 and IL-3/ IL-5/GM-CSF families.

Maintenance of Immune Homeostasis through ILC/T Cell Interactions

Innate lymphoid cells (ILCs) have emerged as a new family of immune cells with crucial functions in innate and adaptive immunity. ILC subsets mirror the cytokine and transcriptional profile of CD4⁺ T helper (T_H) cell subsets. Hence, group 1 (ILC1), group 2 (ILC2), and group 3 (ILC3) ILCs can be distinguished by the production of T_H1, T_H2, and T_H17-type cytokines, respectively. Cytokine release by ILCs not only shapes early innate immunity but can also orchestrate T_H immune responses to microbial or allergen exposure. Recent studies have identified an unexpected effector function of ILCs as antigen presenting cells. Both ILC2s and ILC3s are able to process and present foreign antigens (Ags) via major histocompatibility complex class II, and to induce cognate CD4⁺ T cell responses. In addition, Ag-stimulated T cells promote ILC activation and effector functions indicating a reciprocal interaction between the adaptive and innate immune system. A fundamental puzzle in ILC function is how ILC/T cell interactions promote host protection and prevent autoimmune diseases. Furthermore, the way in which microenvironmental and inflammatory signals determine the outcome of ILC/T cell immune responses in various tissues is not yet understood. This review focuses on recent advances in understanding the mechanisms that coordinate the collaboration between ILCs and T cells under homeostatic and inflammatory conditions. We also discuss the potential roles of T cells and other immune cells to regulate ILC functions and to maintain homeostasis in mucosal tissues.

Langerhans cell-like dendritic cells stimulated with an adjuvant direct the development of Th1 and Th2 cells in vivo

It is well known that Langerhans cells (LCs) work as the primary orchestrators in the polarization of immune responses towards a T helper type 1 (Th1) or Th2 milieu. In this study, we attempted to generate LCs from murine bone marrow cells and elicit a Th1- or Th2-prone immune response through the LCs after stimulation with Th1 or Th2 adjuvant. LCs were generated from murine bone marrow cells using granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-4 and transforming growth factor (TGF)-β, and were obtained as I-A(d) positive cells. Mice were primed with Th1/Th2 adjuvant- and ovalbumin (OVA)-pulsed LCs and then given a booster injection of OVA 2 days later via the hind footpad. Five days after the OVA injection, the cytokine response in the draining popliteal lymph nodes was investigated by reverse transcription-polymerase chain reaction (RT-PCR) flow cytometry and enzyme-linked immunosorbent assay (ELISA). The generated LCs expressed typical LC surface markers, E-cadherin and Langerin, and were classified accordingly as LC-like dendritic cells (LDCs). Administration of Th1 adjuvant, cytosine-phosphate-guanosine (CpG)-DNA- and OVA-pulsed LDCs into the hind footpads of mice induced a Th1-prone immune response, as represented by up-regulation of IFN-γ production and down-regulation of IL-4 production in the lymph node cells. Conversely, Th2 adjuvant, histamine-pulsed LDCs induced a Th2-prone immune response, as represented by up-regulation of IL-4 production and down-regulation of IFN-γ production. These results suggest that LDCs may be used as a substitute for LCs and have the ability to induce the development of Th1 and Th2 cells in vivo. Our experimental system would therefore be useful for screening of inhibitors of Th1/Th2 differentiation in order to control allergic disease.

Recent advances in re-engineered liver: de-cellularization and re-cellularization techniques

Allogeneic transplantation is the definitive treatment for patients with end-stage liver disease but is limited by donor shortage and very high cost. Through de-cellularization and re-cellularization methods, re-engineered liver may provide a promising alternative for treating patients with end-stage liver disease. To achieve this, the prevention of the native extracellular matrix ultrastructure plays a central role in de-cellularization protocol; the re-seeding cell types, as well as re-seeding strategies, need more explorations in re-cellularization protocol. Some success of this approach has been published in a rat model; however, the re-engineered liver remains functional in vivo for only several hours, which suggests that the recent protocol may be far from the ideal target. This Review highlights the challenges still to be overcome and presents an overview and summary of methods of de-cellularization and re-cellularization strategies, together with a view on future directions that may lead to the regeneration of a functional liver.

Immunotherapeutic approaches for cancer therapy: An updated review

In spite of specific immune effector mechanisms raised against tumor cells, there are mechanisms employed by the tumor cells to keep them away from immune recognition and elimination; some of these mechanisms have been identified, while others are still poorly understood. Manipulation or augmentation of specific antitumor immune responses are now the preferred approaches for treatment of malignancies, and traditional therapeutic approaches are being replaced by the use of agents which potentiate immune effector mechanisms, broadly called "immunotherapy". Cancer immunotherapy is generally classified into two main classes including active and passive methods. Interventions to augment the immune system of the patient, for example, vaccination or adjuvant therapy, actively promote antitumor effector mechanisms to improve cancer elimination. On the other hand, administration of specific monoclonal antibodies (mAbs) against different tumor antigens and adoptive transfer of genetically-modified specific T cells are currently the most rapidly developing approaches for cancer targeted therapy. In this review, we will discuss the different modalities for active and passive immunotherapy for cancer.

Improvement in Th1/Th2 immune homeostasis, antioxidative status and resistance to pathogenic E. coli on consumption of probiotic Lactobacillus rhamnosus fermented milk in aging mice

Imbalance in Th1/Th2 immune pathways and cellular antioxidant systems with progressive aging are among the leading causes of increased risk of morbidity and mortality in elderly. Although probiotics have been considered to boost immune system, there is a lack of comprehensive analysis of probiotic effects on aging physiology. The present study aimed at determining anti-immunosenescence potential of milk fermented with probiotic Lactobacillus rhamnosus (LR) in 16 months old mice by concurrent analysis of immunosenescence markers associated with Th1/Th2 profile of splenocytes, inflamm-aging in plasma, neutrophil functions and antibody response in intestine along with analysis of antioxidant enzymes in liver and red blood cells (RBCs) after feeding trials of 1 and 2 months, respectively. An enteropathogenic Escherichia coli (ATCC 14948)-based infection model in aging mice was also designed to validate protective attributes of LR. Splenocytes registered increased IFN-γ and decreased IL-4 and IL-10 production in LR-fed animals. Neutrophil respiratory burst enzymes and phagocytosis increased significantly while no aggravation in plasma levels of MCP-1 and TNF-α was observed. Further, owing to increased Th1 response, antibodies registered a decrease in IgG1/IgG2a ratio and IgE levels in LR groups. No significant variations were observed in secretory IgA and IgA + cells in the intestine. Antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) in LR-fed groups recorded increased activities which were more pronounced in the liver than in RBCs. LR supplementation significantly reduced E. coli translocation to organs (intestine, liver, spleen, peritoneal fluid) by enhancing E. coli-specific antibodies (IgA and IgG1) and inflammatory proteins. In conclusion, LR supplementation alleviated immunosenescence-associated Th1/Th2 imbalance, improved antioxidant capacity, and enhanced resistance of aged mice to E. coli infection thereby signifying its potential in augmenting healthy aging.

Does metabolic reprogramming underpin age-associated changes in T cell phenotype and function?

T cells are required for an effective adaptive immune response. The principal function of T cells is to promote efficient removal of foreign material by identifying and mounting a specific response to nonself. A decline in T cell function in aging is thought to contribute to reduced response to infection and vaccination and an increase in autoimmunity. This may in part be due to the age-related decrease in naïve CD4(+) T cells and increase in antigen-experienced CD4(+) T cells, loss of redox homeostasis, and impaired metabolic switching. Switching between subsets is triggered by the integration of extracellular signals sensed through surface receptors and the activation of discrete intracellular metabolic pathways. This article explores how metabolic programming and loss of redox homeostasis during aging may contribute to age-associated changes in T cell phenotype and function.

Characterization of Bone Marrow-Derived Dendritic Cells Developed in Serum-Free Media and their Ability to Prevent Type 1 Diabetes in Nonobese Diabetic Mice

Dendritic cells (DC) have been investigated as a cell-based therapy for Type 1 Diabetes (T1D). BM-DC expanded ex vivo with GM-CSF and IL-4 is typically cultured with fetal bovine serum (FBS). The effect of FBS on NOD BM-DC has not been extensively studied. In the present study we compare BM-DC generated in serum-free culture media (X-VIVO20; FBS−) with BM-DC generated in media containing 10% FBS (RPMI1640/10%FBS; FBS+). We show that FBS− BM-DC display a phenotype and cytokine-producing profile distinct from FBS+ BMDC. Additionally, compared to FBS+ BM-DC, we show evidence of an altered T_h cell response induced by FBS− BM-DC. Finally, we demonstrate that only FBS− BM-DC prevent the onset of T1D and induce increased levels of CD4⁺Foxp3⁺ regulatory T cells as well as a long-lasting β cell-specific T cell response. This study indicates that serum-free media generates a more tolerogenic BM-DC capable of preventing T1D in the NOD mice.

Human parainfluenza virus type 2 vector induces dendritic cell maturation without viral RNA replication/transcription

The dendritic cell (DC), a most potent antigen-presenting cell, plays a key role in vaccine therapy against infectious diseases and malignant tumors. Although advantages of viral vectors for vaccine therapy have been reported, potential risks for adverse effects prevent them from being licensed for clinical use. Human parainfluenza virus type 2 (hPIV2), one of the members of the Paramyxoviridae family, is a nonsegmented and negative-stranded RNA virus. We have developed a reverse genetics system for the production of infectious hPIV2 lacking the F gene (hPIV2ΔF), wherein various advantages for vaccine therapy exist, such as cytoplasmic replication/transcription, nontransmissible infectivity, and extremely high transduction efficacy in various types of target cells. Here we demonstrate that hPIV2ΔF shows high transduction efficiency in human DCs, while not so high in mouse DCs. In addition, hPIV2ΔF sufficiently induces maturation of both human and murine DCs, and the maturation state of both human and murine DCs is almost equivalent to that induced by lipopolysaccharide. Moreover, alkylating agent β-propiolactone-inactivated hPIV2ΔF (BPL-hPIV2ΔF) elicits DC maturation without viral replication/transcription. These results suggest that hPIV2ΔF may be a useful tool for vaccine therapy as a novel type of paramyxoviral vector, which is single-round infectious vector and has potential adjuvant activity.

Distinct pathways of humoral and cellular immunity induced with the mucosal administration of a nanoemulsion adjuvant

Nasal administration of an oil-in-water nanoemulsion (NE) adjuvant W805EC produces potent systemic and mucosal, Th-1- and Th-17-balanced cellular responses. However, its molecular mechanism of action has not been fully characterized and is of particular interest because NE does not contain specific ligands for innate immune receptors. In these studies, we demonstrate that W805EC NE adjuvant activates innate immunity, induces specific gene transcription, and modulates NF-κB activity via TLR2 and TLR4 by a mechanism that appears to be distinct from typical TLR agonists. Nasal immunization with NE-based vaccine showed that the TLR2, TLR4, and MyD88 pathways and IL-12 and IL-12Rβ1 expression are not required for an Ab response, but they are essential for the induction of balanced Th-1 polarization and Th-17 cellular immunity. NE adjuvant induces MHC class II, CD80, and CD86 costimulatory molecule expression and dendritic cell maturation. Further, upon immunization with NE, adjuvant mice deficient in the CD86 receptor had normal Ab responses but significantly reduced Th-1 cellular responses, whereas animals deficient in both CD80 and CD86 or lacking CD40 failed to produce either humoral or cellular immunity. Overall, our data show that intranasal administration of Ag with NE induces TLR2 and TLR4 activation along with a MyD88-independent Ab response and a MyD88-dependent Th-1 and Th-17 cell-mediated immune response. These findings suggest that the unique properties of NE adjuvant may offer novel opportunities for understanding previously unrecognized mechanisms of immune activation important for generating effective mucosal and systemic immune responses.

Dendritic cell subsets in type 1 diabetes: friend or foe?

Type 1 diabetes (T1D) is a T cell mediated autoimmune disease characterized by immune mediated destruction of the insulin-producing β cells in the islets of Langerhans. Dendritic cells (DC) have been implicated in the pathogenesis of T1D and are also used as immunotherapeutic agents. Plasmacytoid (p)DC have been shown to have both protective and pathogenic effects and a newly described merocytic DC population has been shown to break tolerance in the mouse model of T1D, the non-obese diabetic (NOD) mouse. We have used DC populations to prevent the onset of T1D in NOD mice and clinical trials of DC therapy in T1D diabetes have been initiated. In this review we will critically examine the recent published literature on the role of DC subsets in the induction and regulation of the autoimmune response in T1D.

The Pseudomonas aeruginosa Mannose Sensitive Hamemagglutination Strain (PA-MSHA) Induces a Th1-Polarizing Phenotype by Promoting Human Dendritic Cells Maturation

Pseudomonas aeruginosa mannose sensitive hamemagglutination strain (PA-MSHA) is a kind of peritrichous P. aeruginosa strain with MSHA fimbriae and has been shown to activate kinds of immunocytes. Dendritic cells (DCs) are specialized antigen-presenting cells required for the stimulating and priming CD4(+) T cells toward the T helper cell type 1 (Th1), Th2 and other different phenotypes. PA-MSHA effecting on Th1 remains an important missing link. Here we demonstrated that PA-MSHA augmented monocytes derived-dendritic cells (Mo-DCs) expression of HLA-DR, co-stimulatory and adhesion molecules, and induced Th1-promoting interleukin-12 and tumor necrosis factor α secretion, in addition, PA-MSHA treated Mo-DCs displayed lesser endocytic capacity. Furthermore, in mixed lymphocyte reactions, allostimulatory capacity of Mo-DCs was enhanced by PA-MSHA, CD4(+) T cells stimulated by PA-MSHA -activated Mo-DCs showed a Th1-polarized cytokine production, increasing secretion of IFN-γ and decreasing secretion of IL-10 and IL-4. Our findings identified PA-MSHA as an important exogenous factor that induced DCs maturation toward a Th1-promoting phenotype.

Assessment of immunosuppressive activity of human mesenchymal stem cells using murine antigen specific CD4 and CD8 T cells in vitro

Introduction

Mesenchymal stem cells (MSCs) have immunosuppressive activity. They do not induce allospecific T cell responses, making them promising tools for reducing the severity of graft versus host disease (GVHD) as well as treating various immune diseases. Currently, there is a need in the MSC field to develop a robust in vitro bioassay which can characterize the immunosuppressive function of MSCs.

Methods

Murine clonal CD4 and CD8 T cells were stimulated with cognate peptide antigen and antigen presenting cells (APCs) in the absence or presence of human MSCs, different aspects of T cell activation were monitored and analyzed using flow cytometery, real time RT-PCR and cytokine measurement.

Results

Human MSCs (hMSCs) can alter multiple aspects of murine T cell activation induced by stimulation with specific antigen, including: reduced proliferation, inhibited or stimulated cell surface marker expression (CD25, CD69, CD44 and CD62L), inhibited mRNA expression of transcription factors (T-bet and GATA-3) and decreased cytokine expression (interferon-gamma, interleukin-10). Disappearance of activation-induced cluster formation and decreased apoptosis of CD8 T cells were also observed. Moreover, the effects are specific to MSCs; incubating the T cells with non-MSC control cell lines had no effect on T cell proliferation and activation.

Conclusions

Clonal murine T cells can be used to measure, characterize, and quantify the in vitro immunosuppressive activity of human MSCs, representing a promising approach to improve bioassays for immunosuppression.

A novel subset of helper T cells promotes immune responses by secreting GM-CSF

Helper T cells are crucial for maintaining proper immune responses. Yet, they have an undefined relationship with one of the most potent immune stimulatory cytokines, granulocyte macrophage-colony-stimulating factor (GM-CSF). By depleting major cytokines during the differentiation of CD4(+) T cells in vitro, we derived cells that were found to produce large amounts of GM-CSF, but little of the cytokines produced by other helper T subsets. By their secretion of GM-CSF, this novel subset of helper T cells (which we have termed ThGM cells) promoted the production of cytokines by other T-cell subtypes, including type 1 helper T cell (Th1), type 2 helper T cell (Th2), type 1 cytotoxic T cell (Tc1), type 2 cytotoxic T cell (Tc2), and naive T cells, as evidenced by the fact that antibody neutralization of GM-CSF abolished this effect. ThGM cells were found to be highly prone to activation-induced cell death (AICD). Inhibitors of TRAIL or granzymes could not block AICD in ThGM cells, whereas inhibition of FasL/Fas interaction partially rescued ThGM cells from AICD. Thus, ThGM cells are a novel subpopulation of T helper cells that produce abundant GM-CSF, exhibit exquisite susceptibility to apoptosis, and therefore play a pivotal role in the regulation of the early stages of immune responses.

A unique dermal dendritic cell subset that skews the immune response toward Th2

Dendritic cell (DC) subsets in the skin and draining lymph nodes (LNs) are likely to elicit distinct immune response types. In skin and skin-draining LNs, a dermal DC subset expressing macrophage galactose-type C-type lectin 2 (MGL2/CD301b) was found distinct from migratory Langerhans cells (LCs) or CD103⁺ dermal DCs (dDCs). Lower expression levels of Th1-promoting and/or cross-presentation-related molecules were suggested by the transcriptome analysis and verified by the quantitative real-time PCR analysis in MGL2⁺ dDCs than in CD103⁺ dDCs. Transfer of MGL2⁺ dDCs but not CD103⁺ dDCs from FITC-sensitized mice induced a Th2-type immune response in vivo in a model of contact hypersensitivity. Targeting MGL2⁺ dDCs with a rat monoclonal antibody against MGL2 efficiently induced a humoral immune response with Th2-type properties, as determined by the antibody subclass. We propose that the properties of MGL2⁺ dDCs, are complementary to those of CD103⁺ dDCs and skew the immune response toward a Th2-type response.

Cis association of galectin-9 with Tim-3 differentially regulates IL-12/IL-23 expressions in monocytes via TLR signaling

Human monocytes/macrophages (M/M_Ф) of the innate immunity sense and respond to microbial products via specific receptor coupling with stimulatory (such as TLR) and inhibitory (such as Tim-3) receptors. Current models imply that Tim-3 expression on M/M_Ø can deliver negative signaling to TLR-mediated IL-12 expression through trans association with its ligand Galectin-9 (Gal-9) presented by other cells. However, Gal-9 is also expressed within M/M_Ø, and the effect of intracellular Gal-9 on Tim-3 activities and inflammatory responses in the same M/M_Ø remains unknown. In this study, our data suggest that Tim-3 and IL-12/IL-23 gene transcriptions are regulated by enhanced or silenced Gal-9 expression within monocytes through synergizing with TLR signaling. Additionally, TLR activation facilitates Gal-9/Tim-3 cis association within the same M/M_Ø to differentially regulate IL-12/IL-23 expressions through STAT-3 phosphorylation. These results reveal a ligand (Gal-9) compartment-dependent regulatory effect on receptor (Tim-3) activities and inflammatory responses via TLR pathways—a novel mechanism underlying cellular responses to external or internal cues.

Interleukin-15 dendritic cells as vaccine candidates for cancer immunotherapy

Owing to their professional antigen-presenting capacity and unique potential to induce tumor antigen-specific T cell immunity, dendritic cells (DCs) have attracted much interest over the past decades for therapeutic vaccination against cancer. Clinical trials have shown that the use of tumor antigen-loaded DCs in cancer patients is safe and that it has the potential to induce anti-tumor immunity which, in some cases, culminates in striking clinical responses. Unfortunately, in a considerable number of patients, DC vaccination is unable to mount effective anti-tumor immune responses and, if it does so, the resultant immunity is often insufficient to translate into tangible clinical benefit. This underscores the necessity to re-design and optimize the current procedures for DC vaccine manufacturing. A new generation of DC vaccines with improved potency has now become available for clinical use as a result of extensive pre-clinical research. One of the promising next-generation DC vaccine candidates are interleukin (IL)-15-differentiated DCs. In this commentary, we will compile the research data that have been obtained by our group and other groups with these so-called IL-15 DCs and summarize the evidence supporting the implementation of IL-15 DCs in DC-based cancer vaccination regimens.

Dendritic cell-based vaccines: barriers and opportunities

Dendritic cells (DCs) have several characteristics that make them an ideal vehicle for tumor vaccines, and with the first US FDA-approved DC-based vaccine in use for the treatment of prostate cancer, this technology has become a promising new therapeutic option. However, DC-based vaccines face several barriers that have limited their effectiveness in clinical trials. A major barrier includes the activation state of the DC. Both DC lineage and maturation signals must be selected to optimize the antitumor response and overcome immunosuppressive effects of the tumor microenvironment. Another barrier to successful vaccination is the selection of target antigens that will activate both CD8(+) and CD4(+) T cells in a potent, immune-specific manner. Finally, tumor progression and immune dysfunction limit vaccine efficacy in advanced stages, which may make DC-based vaccines more efficacious in treating early-stage disease. This review underscores the scientific basis and advances in the development of DC-based vaccines, focuses on current barriers to success and highlights new research opportunities to address these obstacles.

Tim-3 alters the balance of IL-12/IL-23 and drives TH17 cells: role in hepatitis B vaccine failure during hepatitis C infection

Hepatitis B virus (HBV) vaccination is recommended for individuals with hepatitis C virus (HCV) infection given their shared risk factors and increased liver-related morbidity and mortality upon super-infection. Vaccine responses in this setting are often blunted, with poor response rates to HBV vaccinations in chronically HCV-infected individuals compared to healthy subjects. In this study, we investigated the role of T cell immunoglobulin mucin domain-3 (Tim-3)-mediated immune regulation in HBV vaccine responses during HCV infection. We found that Tim-3, a marker for T cell exhaustion, was over-expressed on monocytes, leading to a differential regulation of IL-12/IL-23 production which in turn TH17 cell accumulation, in HCV-infected HBV vaccine non-responders compared to HCV-infected HBV vaccine responders or healthy subjects (HS). Importantly, ex vivo blockade of Tim-3 signaling corrected the imbalance of IL-12/IL-23 as well as the IL-17 bias observed in HBV vaccine non-responders during HCV infection. These results suggest that Tim-3-mediated dysregulation of innate to adaptive immune responses is involved in HBV vaccine failure in individuals with chronic HCV infection, raising the possibility that blocking this negative signaling pathway might improve the success rate of HBV immunization in the setting of chronic viral infection.

Differential regulation of interleukin-12 (IL-12)/IL-23 by Tim-3 drives T(H)17 cell development during hepatitis C virus infection

Cytokine production by innate immunity is critical for shaping the adaptive immunity through regulation of T cell differentiation. In this report, we studied T cell immunoglobulin mucin domain protein 3 (Tim-3) expression on monocytes and its regulatory effect on interleukin-12 (IL-12)/IL-23 production by CD14(+) monocytes, as well as IL-17 production by CD4(+) T cells in individuals with chronic hepatitis C virus (HCV) infection. We found that Tim-3 and IL-23p19 are highly expressed and that IL-12p35 is inhibited in human CD14(+) monocytes, while IL-17 expression is upregulated in CD4(+) T cells, in chronically HCV-infected individuals compared to healthy subjects. Interestingly, Tim-3 expression is closely associated with the differential regulation of IL-12/IL-23 expression in CD14(+) monocytes and correlated to IL-17 production by CD4(+) T cells. These Tim-3-associated IL-12/IL-23/IL-17 dysregulations in HCV-infected individuals are also recapitulated in vitro by incubating healthy monocytes or peripheral blood mononuclear cells with Huh-7 hepatoma cells transfected with HCV RNA. Importantly, blocking Tim-3 signaling on monocytes restores the balance of IL-12/IL-23 through the intracellular STAT3 signaling, which in turn reverses the upregulated IL-17 expression both ex vivo and in vitro. Our findings suggest that Tim-3-mediated differential regulation of IL-12/IL-23 drives T(H)17 cell development, a milieu favoring viral persistence and autoimmune phenomenon during HCV infection.

Gene therapy for brain tumors: basic developments and clinical implementation

Glioblastoma multiforme (GBM) is the most common and deadliest of adult primary brain tumors. Due to its invasive nature and sensitive location, complete resection remains virtually impossible. The resistance of GBM against chemotherapy and radiotherapy necessitate the development of novel therapies. Gene therapy is proposed for the treatment of brain tumors and has demonstrated pre-clinical efficacy in animal models. Here we review the various experimental therapies that have been developed for GBM including both cytotoxic and immune stimulatory approaches. We also review the combined conditional cytotoxic immune stimulatory therapy that our lab has developed which is dependent on the adenovirus mediated expression of the conditional cytotoxic gene, Herpes Simplex Type 1 Thymidine Kinase (TK) and the powerful DC growth factor Fms-like tyrosine kinase 3 ligand (Flt3L). Combined delivery of these vectors elicits tumor cell death and an anti-tumor adaptive immune response that requires TLR2 activation. The implications of our studies indicate that the combined cytotoxic and immunotherapeutic strategies are effective strategies to combat deadly brain tumors and warrant their implementation in human Phase I clinical trials for GBM.

Dendritic cells and the maintenance of self-tolerance

Dendritic cells (DC) play important roles in the initiation of immune responses and in the maintenance of self-tolerance. We have been studying the role of DC in the pathogenesis of type 1 diabetes and exploring the ability of specific DC subsets to prevent diabetes in non-obese diabetic (NOD) mice. DC presenting low doses of antigen are capable of inducing and expanding T-regulatory (Treg) cells that have potent suppressive function. We review here our recent findings in this area and highlight the ability of semi-mature therapeutic DC to induce Treg expansion in the absence of exogenous antigen. We discuss how the presentation of endogenous self-antigen by DC may represent a natural mechanism for peripheral self-tolerance that can be harnessed to prevent autoimmunity.

Modulation of Th1/Th2 balance by Lactobacillus strains isolated from Kimchi via stimulation of macrophage cell line J774A.1 in vitro

Lactobacilli isolated from Kimchi, a Korean traditional food, were tested for their capacity to modulate the T helper (Th) 1/Th2 balance. Ovalbumin (OVA)-sensitized mouse splenocytes were cultured with 26 strains of lactobacilli; the highest IL-12 induction and lowest IL-4 production were then observed in 4 strains, including Lactobacillus plantarum CJLP55, CJLP56, CJLP133, and CJLP136. These strains produced a larger amount of IL-12, which enhances differentiation and activation of Th1 cells, in macrophage cell-lines more than positive control strains L. casei KCTC 3109(T) and L. rhamnosus GG, although they also induced production of IL-10, which is a suppressor of IL-12. Indeed, CJLP133-stimulated macrophages induced production of more Th1 cytokine IFN-γ and less Th2 cytokine IL-4 than KCTC 3109(T) and GG in co-cultivation with T cells. These findings suggest that lactobacilli from Kimchi may modulate the Th1/Th2 balance via macrophage activation in the hypersensitive reaction caused by Th2 cells.

PRACTICAL APPLICATION

Allergic reactions including asthma and atopy are caused by predominance of Th2 response over Th1 response. Lactobacilli isolated from fermented foods such as yogurt, cheese, and Kimchi showed health-promoting activities. The present study indicated that several lactobacilli strains from Kimchi may reduce allergic reactions through macrophage-mediated induction of Th1 response.

Interleukin-4 enhances trafficking and functional activities of GM-CSF-stimulated mouse myeloid-derived dendritic cells at late differentiation stage

Mouse bone marrow-derived dendritic cells (BMDCs) are being employed as an important model for translational research into the development of DC-based therapeutics. For such use, the localization and specialized mobility of injected BMDCs within specific immune tissues are known to define their immunity and usefulness in vivo. In this study, we demonstrate that IL-4, a key driving factor for in vitro propagation and differentiation of BMDCs, when added during a late culture stage can enhance the in vivo trafficking activity of granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced BMDCs. It suggests that the temporal control of IL-4 stimulation during the in vitro generation of DCs drastically affects the DC trafficking efficiency in vivo. With this modification of IL-4 stimulation, we also show that much less cytokine was needed to generate BMDCs with high purity and yield that secrete a high level of cytokines and possess a good capacity to induce proliferation of allogeneic CD4+ T cells, as compared to the conventional method that uses a continuous supplement of GM-CSF and IL-4 throughout cultivation. These results provide us with an important know-how for differentiation of BMDCs from myeloid stem cells, and for use of other immune cells in related medical or stem cell applications.

Poly(methyl vinyl ether-co-maleic anhydride) nanoparticles as innate immune system activators

Adjuvant research is being oriented to TLR-agonists, but complement activation has been relatively unexplored. In previous studies it was demonstrated that poly(methyl vinyl ether-co-maleic anhydride) nanoparticles (PVMA NPs) used as adjuvant differentially activate dendritic cells through toll like receptors (TLR) stimulation, however, a high dose of these NPs was used. Now, we demonstrated a dose-response effect, with a concentration as low as 20μg/mL able to stimulate TLR2 and TLR4 transfected dendritic cells. In addition, we investigated whether PVMA NPs are able to exploit also the immunomodulatory benefits of complement activation. Results indicated that the hydroxylated surface of these NPs highly activated the complement cascade, as measured by adsorption studies and a complement fixation bioassay. Stable binding of C3b to NPs was confirmed as indicated by lability to SDS treatment after washing resistance. Complement consumption was confirmed as the lytic capacity of complement exposed to NPs was abolished against antibody-sensitized sheep erythrocytes, with a minimal inhibitory concentration of 50μg NPs, equivalent to a surface of 1cm(2). On the contrary, nanoparticles prepared with poly(lactic-co-glycolic acid) (PLGA), used as a reference, did not consume complement at a concentration ≥3mg NPs (≥40cm(2)). Complement consumption was inhibited when PVMA NPs were cross-linked with diamino groups (1,3-diaminopropane), indicating the role of hydroxyl groups as responsible of the phenomenon. These results favour a model whereby PVMA NPs adjuvant activate complement on site to attract immature antigen presenting cells that are activated through TLR2 and TLR4.

Mast cells promote Th1 and Th17 responses by modulating dendritic cell maturation and function

Mast cells (MCs) play an important role in the regulation of protective adaptive immune responses against pathogens. However, it is still unclear whether MCs promote such host defense responses via direct effects on T cells or rather by modifying the functions of antigen-presenting cells. To identify the underlying mechanisms of the immunoregulatory capacity of MCs, we investigated the impact of MCs on dendritic cell (DC) maturation and function. We found that murine peritoneal MCs underwent direct crosstalk with immature DCs that induced DC maturation as evidenced by enhanced expression of costimulatory molecules. Furthermore, the MC/DC interaction resulted in the release of the T-cell modulating cytokines IFN-γ, IL-2, IL-6 and TGF-β into coculture supernatants and increased the IL-12p70, IFN-γ, IL-6 and TGF-β secretion of LPS-matured DCs. Such MC-"primed" DCs subsequently induced efficient CD4+ T-cell proliferation. Surprisingly, we observed that MC-primed DCs stimulated CD4+ T cells to release high levels of IFN-γ and IL-17, demonstrating that MCs promote Th1 and Th17 responses. Confirming our in vitro findings, we found that the enhanced disease progression of MC-deficient mice in Leishmania major infection is correlated with impaired induction of both Th1 and Th17 cells.

Gene expression analysis of dendritic cells that prevent diabetes in NOD mice: analysis of chemokines and costimulatory molecules

We have demonstrated previously that BM-derived DCs can prevent diabetes development and halt progression of insulitis in NOD mice, the mouse model of type 1 diabetes. The DC population that was most effective in this therapy had a mature phenotype, expressed high levels of costimulatory molecules, and secreted low levels of IL-12p70. The protective DC therapy induced Treg and Th2 cells in vitro and in vivo. Microarray analysis of therapeutic and nontherapeutic DC populations revealed differences in the expression of OX40L, CD200, Ym-1, CCL2, and CCL5, which could play important roles in the observed DC-mediated therapy. The unique pattern of costimulatory molecules and chemokines expressed by the therapeutic DCs was confirmed by flow cytometry and ELISA. Using a novel cell-labeling and (19)F NMR, we observed that the chemokines secreted by the therapeutic DCs altered the migration of diabetogenic Th1 cells in vivo and attracted Th2 cells. These results suggest that the therapeutic function of DCs is mediated by a combination of costimulatory and chemokine properties that results in the attraction of diabetogenic Th1 and the induction of Th2 and/or Treg differentiation.

Effects of hydrocortisone on the differentiation of human T helper 2 cells

We investigated the effects of the neuroendocrine modulator hydrocortisone (HC) on Th2 differentiation of human naive CD4+ T cells with and without CD28 co-stimulation. Human naive CD4+ T cells were isolated and purified from umbilical cord blood mononuclear cells from full-term newborn infants. CD4+ T cells were treated with different concentrations of HC under Th0 or Th2 culture conditions. Th0 conditions included stimulation by immobilized monoclonal antibodies (mAbs) against CD3 and CD28; Th2 conditions were the same + rhIL-4. Parallel cultures excluded the CD28 mAb. Th1 (IL-2, INF-γ)- and Th2 (IL-4, IL-5)-type cytokines were quantified in culture supernatants by ELISA and within cells by flow cytometry. For both Th0 and Th2 culture conditions, HC significantly inhibited Th1 cytokines' release (IL-2 and INF-γ). For Th0 culture conditions, HC slightly increased IL-4 expression (Th2 cytokine). However, for Th2 culture conditions, HC inhibited the IL4-induced production of IL-4. Although the absolute cytokine amounts were decreased, absence of CD28 co-stimulation did not alter these 'trends'. Our findings indicate that HC can alter the Th1/Th2 balance by inhibiting the production of Th1-type cytokines. HC can also diminish the extensive Th2 differentiation induced by IL-4.

Fibroblasts stimulated via HLA-II molecules produce prostaglandin E₂ and regulate cytokine production from helper T cells

Fibroblasts act as important immune regulatory cells via their ability to cross-talk with T cells accumulating in lesions. Our previous study showed that fibroblasts produce several cytokines and chemokines by crosslinking HLA class II (HLA-II) molecules with monoclonal antibodies or by making T-cell receptor-peptide-HLA complexes. It is thus conceivable that the interaction of T cells and fibroblasts via HLA-II affects fibroblast responses to stimuli. This study used human gingival fibroblasts (HGF) to investigate possible effects of these fibroblast-derived soluble factors on the differentiation of naïve T cells and on the subsequent fibroblast responses. After mixed lymphocyte reaction culture between naïve T cells and allogeneic dendritic cells in the presence of culture supernatant from HGF stimulated via HLA-DQ molecules (DQ-sup), but not via DR, T cells exhibited a Th2-shifted phenotype, thereby producing quantitatively more IL-13 and IL-5 compared with interferon-γ. Astonishingly, analyses to identify possible factors affecting the Th2 polarization secreted from HLA-II-stimulated HGF, prostaglandin E₂, was detected only in DQ-sup. The Th2 polarization of naïve T cells was blocked in the presence of supernatants from indomethacin-treated HGF with HLA-DQ stimulation. In addition, we found that the culture supernatants of Th cells activated following mixed lymphocyte reaction culture in the presence of DQ-sup had the potential to induce gene expression of type I and III collagens in HGF. These results suggested that fibroblasts stimulated via HLA-DQ molecules promote Th2 polarization in Th-cell responses and showed the counter activation of collagen synthesis, implicating orchestrated responses among these cells in the fibrosis of chronic inflammatory lesions.

Pathogenesis of allergic airway inflammation

Advances have been made in defining the mechanisms for the control of allergic airway inflammation in response to inhaled antigens. Several genes, including ADAM33, DPP10, PHF11, GPRA, TIM-1, PDE4D, OPN3, and ORMDL3, have been implicated in the pathogenesis and susceptibility to atopy and asthma. Growing evidence associates asthma with a systemic propensity for allergic T-helper type 2 cytokines. Disordered coagulation and fibrinolysis also exacerbate asthma symptoms. Balance among functionally distinct dendritic cell subsets contributes to the outcome of T-cell-mediated immunity. Allergen-specific T-regulatory cells play a pivotal role in the development of tolerance to allergens and immune suppression. The major emphasis on immunotherapy for asthma during the past decade has been to direct the immune response to a type 1 response, or immune tolerance. In this review, we discuss the current information on the pathogenesis of allergic airway inflammation and potential immunotherapy, which could be beneficial in the treatment of airway inflammation, allergy, and asthma.

Dendritic cells lentivirally engineered to overexpress interleukin-10 inhibit contact hypersensitivity responses, despite their partial activation induced by transduction-associated physical stress

BACKGROUND

Dendritic cells (DCs) constitute an attractive target for immunotherapeutic approaches. Because DCs are largely refractory to transfection with plasmid DNA, several viral transduction protocols were established. The potential side-effects of lentiviral transduction on the phenotype and activation state of DCs left unstimulated after transduction have not been assessed. There is a need to analyse these parameters as a result of the requirement of using DCs with a low activation state for therapeutic strategies intended to induce tolerance.

METHODS

Lentivirally-transduced bone marrow (BM)-derived DCs (LV-DCs) in comparison with mock-transduced (Mock-DCs) and untreated DCs were analysed with regard to the induction of maturation processes on the RNA, protein and functional level. BM-DCs engineered to overexpress interleukin (IL)-10 were analysed for therapeutic potential in a mouse model of allergic contact dermatitis.

RESULTS

Compared with untreated DCs, Mock-DCs and LV-DCs displayed an altered gene expression signature. Mock-DCs induced a stronger T cell proliferative response than untreated DCs. LV-DCs did not further augment the T cell proliferative response, but induced a slightly different T cell cytokine pattern compared to Mock-DCs. Accordingly, the gene promoter of the DC maturation marker fascin mediated efficient expression of the model transgene IL-10 in unstimulated-transduced BM-DCs. Nevertheless, IL-10 overexpressing BM-DCs exerted tolerogenic activity and efficiently inhibited the contact hypersensitivity response in previously hapten-sensitized mice.

CONCLUSIONS

Lentiviral transduction of BM-DCs results in their partial activation. Nevertheless, the transduction of these DCs with a vector encoding the immunomodulatory cytokine IL-10 rendered them tolerogenic. Thus, lentivirally-transduced DCs expressing immunomodulatory molecules represent a promising tool for induction of tolerance.

Antigen aggregation decides the fate of the allergic immune response

Previously, defined naturally occurring isoforms of allergenic proteins were classified as hypoallergens and therefore suggested as an agent for immunotherapy in the future. In this paper, we report for the first time the molecular background of hypoallergenicity by comparing the immunological behavior of hyperallergenic Betula verrucosa major Ag 1a (Bet v 1a) and hypoallergenic Bet v 1d, two isoforms of the major birch pollen allergen Betula verrucosa 1. Despite their cross-reactivity, Bet v 1a and Bet v 1d differ in their capacity to induce protective Ab responses in BALB/c mice. Both isoforms induced similar specific IgE levels, but only Bet v 1d expressed relevant titers of serum IgGs and IgAs. Interestingly, hypoallergenic Bet v 1d activated dendritic cells more efficiently, followed by the production of increased amounts of Th1- as well as Th2-type cytokines. Surprisingly, compared with Bet v 1a, Bet v 1d-immunized mice showed a decreased proliferation of regulatory T cells. Crystallographic studies and dynamic light scattering revealed that Bet v 1d demonstrated a high tendency to form disulfide-linked aggregates due to a serine to cysteine exchange at residue 113. We conclude that aggregation of Bet v 1d triggers the establishment of a protective Ab titer and supports a rationale for Bet v 1d being a promising candidate for specific immunotherapy of birch pollen allergy.