Allergy immunotherapy and inhibition of Th2 immune responses: a sufficient strategy?

Dupilumab and subcutaneous immunotherapy for the treatment of refractory moderate to severe atopic dermatitis: A preliminary report

Subcutaneous immunotherapy (SCIT) and dupilumab are important treatments for patients with moderate to severe atopic dermatitis (AD). However, in clinical practice, poor response to allergen immunotherapy (AIT) or dupilumab has been observed in some patients. It is unknown whether combining dupilumab and SCIT can improve treatment responses in patients with moderate to severe AD that is resistant to dupilumab or SCIT monotherapy. This single-centre, retrospective, observational, real-world study evaluated the efficacy and safety of dupilumab and SCIT for refractory moderate to severe AD. The data of ten patients with moderate to severe atopic dermatitis who were treated with dupilumab and SCIT were retrospectively analysed. The scoring atopic dermatitis (SCORAD) score, numerical rating scale (NRS), and atopic dermatitis control test (ADCT) scores and eosinophil and total IgE levels before and after add-on therapy were compared and analysed. The SCORAD, NRS, and ADCT scores decreased significantly at four and 12 weeks after the initiation of add-on therapy and plateaued during maintenance treatment. The eosinophil and total IgE levels were not significantly different before and after add-on therapy. No serious adverse reactions were reported in any patient during add-on therapy. This study indicates that the combination of dupilumab and SCIT safely improves the treatment response of patients with moderate to severe AD who are resistant to dupilumab or SCIT monotherapy.

Computationally grafting an IgE epitope onto a scaffold: Implications for a pan anti-allergy vaccine design

Allergy is becoming an intensifying disease among the world population, particularly in the developed world. Once allergy develops, sufferers are permanently trapped in a hyper-immune response that makes them sensitive to innocuous substances. The immune pathway concerned with developing allergy is the Th2 immune pathway where the IgE antibody binds to its Fc ∊ RI receptor on Mast and Basophil cells. This paper discusses a protocol that could disrupt the binding between the antibody and its receptor for a potential permanent treatment. Ten proteins were computationally designed to display a human IgE motif very close in proximity to the IgE antibody's Fc ∊ RI receptor's binding site in an effort for these proteins to be used as a vaccine against our own IgE antibody. The motif of interest was the FG loop motif and it was excised and grafted onto a Staphylococcus aureus protein (PDB ID 1YN3), then the motif + scaffold structure had its sequence re-designed around the motif to find an amino acid sequence that would fold to the designed structure correctly. These ten computationally designed proteins showed successful folding when simulated using Rosetta's AbinitioRelax folding simulation and the IgE epitope was clearly displayed in its native three-dimensional structure in all of them. These designed proteins have the potential to be used as a pan anti-allergy vaccine. This work employedin silicobased methods for designing the proteins and did not include any experimental verifications.

IL-2-Agonist-Induced IFN-γ Exacerbates Systemic Anaphylaxis in Food Allergen-Sensitized Mice

Food allergies are common, costly and potentially life-threatening disorders. They are driven by Th2, but inhibited by Th1 reactions. There is also evidence indicating that IL-2 agonist treatment inhibits allergic sensitization through expansion of regulatory T cells. Here, we tested the impact of an IL-2 agonist in a novel model for food allergy to hen´s egg in mice sensitized without artificial adjuvants. Prophylactic IL-2 agonist treatment expanded Treg populations and inhibited allergen-specific sensitization. However, IL-2 agonist treatment of already sensitized mice increased mast cell responses and allergic anaphylaxis upon allergen re-challenge. These effects depended on allergen-specific IgE and were mediated through IFN-γ, as shown by IgE transfer and blockade of IFN-γ with monoclonal antibodies. These results suggest that although shifting the allergic reaction toward a Treg/Th1 response inhibits allergic sensitization, the prototypic Th1 cytokine IFN-γ promotes mast cell activation and allergen-induced anaphylaxis in individuals that are already IgE-sensitized. Hence, while a Th1 response can prevent the development of food allergy, IFN-γ has the ability to exacerbate already established food allergy.

Preventive effects of a novel herbal mixture on atopic dermatitis-like skin lesions in BALB/C mice

BACKGROUND

A combination of parts of Cornus officinalis, Rosa multiflora, Lespedeza bicolor, Platycladus orientalis, and Castanea crenata is commonly used for alleviating inflammatory skin disorders. Therefore, this study was carried out to evaluate the in vitro and in vivo preventive effects of a novel herbal formula made from the five plants (C2RLP) against atopic dermatitis in BALB/C mice.

METHODS

Mice were allocated into five groups (n = 8) including, control (Normal, petrolatum, and betamethasone treated) and treatment groups (treated with 2.5 and 5% C2RLP ointment). Atopic lesion was induced by applying 1-Chloro-2, 4-dinitrobenzene to the dorsal thoracic area of mice. Macroscopical and histological evaluations were performed to determine the effects of treatment on the progress of the skin lesions. The effects of treatment on the production and release of interleukins, interferon -ϒ, nitrite, prostaglandin E2, thymus and activation-receptor chemokine, and β-hexosaminidase were evaluated and comparisons were made between groups. In addition, the chemical compounds present in C2RLP were identified by Liquid Chromatography-Mass Spectrometry.

RESULTS

Topical application of C2RLP reduced the dermatitis score and suppressed histopathological changes in mice. Treatment significantly reduced (P < 0.05) plasma IL-4 level, the production of nitrite, prostaglandin E2, and thymus and activation-receptor chemokine production. The lipopolysaccharide-induced iNOS-mRNA expression in RAW 264.7 cells was also suppressed by high concentrations of C2RLP. In addition, C2RLP showed an inhibitory effect against DPPH free radical (IC50 = 147.5 μg/ml) and β-hexosaminidase release (IC50 = 179.5 μg/ml). Liquid Chromatography-Mass Spectrometry analysis revealed the presence of various compounds, including loganin, ellagic acid, and kaempferol 3-glucoside.

CONCLUSION

Down-regulation of T- helper 2 cellular responses and suppression of inflammatory mediators contributed to the protective effects of C2RLP from atopic dermatitis in BALB/C mice.

The Anti-Inflammatory Effect of Fructus Kochiae on Allergic Contact Dermatitis Rats via pERK1/2/TLR4/NF-κB Pathway Activation

Allergic contact dermatitis (ACD) is a common irritability skin disease, which can be cured by using the Chinese patent medicine. To explore the pharmacological effect of total flavonoids of Fructus Kochiae (FK) on ACD, we used dinitrochlorobenzene- (DNCB-) induced ACD rats. Five groups were used in our experiments. The normal group and the DNCB group were treated with 0.5% CMC-Na; the DNCB + hFK group was treated with a high dose of total flavonoids of FK (200 mg/kg); the DNCB + lFK group was treated with a low dose of FK (100 mg/kg); the DNCB + Pre group was treated with prednisolone acetate (2.5 mg/kg). The results showed that FK treatment had significantly attenuated the inflammation induced by DNCB. The increased concentration of cytokines including IL-6, IL-18, and IFN-γ in ACD rats could be reversed by the FK administration, while IL-10 expressed the opposite result; the expression level of TLR4, pERK_1/2, and NF-κB could be downregulated by the treatment with FK in the ACD rat. In a word, the total flavonoids of the FK had an anti-inflammatory effect on the DNCB-induced ACD rat; this regulatory mechanism was highly possible based on the pERK_1/2/TLR4-NF-κB pathway activation.

A Herbal Formula, Atofreellage, Ameliorates Atopic Dermatitis-Like Skin Lesions in an NC/Nga Mouse Model

We evaluated the anti-atopic dermatitis (AD) effect of Atofreellage (AF), a herbal formula composed of 10 medicinal plants. AD was induced on the dorsal skin areas of NC/Nga mice (male, seven weeks old) by daily application of 2,4-dinitrochlorobenzene (DNCB) for five weeks. After three weeks of DNCB application, 200 μL of AF (0, 25, 50 or 100 mg/mL) was applied to the skin lesions. Histological findings, blood cell populations, serum levels of immunoglobulin E (IgE), histamine, pro-inflammatory cytokines, and inflammatory signaling in the skin tissue, and T-helper cell type 2 (Th₂)-related cytokines in splenocytes were analyzed. Histopathological findings showed AF treatment notably attenuated the thickness of dorsal skin, and eosinophil infiltration. AF treatment (especially 100 mg/mL) also demonstrably ameliorated the blood cell population abnormalities, as the notable elevation of serum concentrations of IgE, histamine, TNF-α, IL-6 and IL-1β were remarkably normalized by AF treatment. Western blot analysis evidenced the apparent normalization of inflammatory signals (ERK, p38 MAP kinase, JNK, and NF-κB) in the skin tissue. Additionally, AF treatment notably attenuated the activation of Th₂-dominant cytokines (IL-13, IL-4, and IL-5) in Con A-treated splenocytes in an ex vivo assay. In conclusion, this study provides experimental evidence for the clinical relevance of Atofreellage.

Effects of subchronic exposure to low-dose volatile organic compounds on lung inflammation in mice

Inflammatory lung diseases are characterized by chronic inflammation and oxidant/antioxidant imbalance. Exposure to some kinds of volatile organic compounds (VOCs) leads to lung inflammation, oxidative stress, and immune modulation. However, it is suspected that sub-chronic exposure to low-dose VOCs mixture induces or aggravates lung inflammation. To clarify the effect of this exposure on lung inflammatory responses, 40 male Kunming mice were exposed in four similar static chambers, 0 (control) and three different doses of VOCs mixture (groups 1-3). The concentrations of VOCs mixture were as follows: formaldehyde, benzene, toluene, and xylene 0.10 + 0.11 + 0.20 + 0.20 mg/m(3) , 0.50 + 0.55 + 1.00 + 1.00 mg/m(3) , 1.00 + 1.10 + 2.00 + 2.00 mg/m(3) , respectively, which corresponded to 1, 5, and 10 times of indoor air quality standard in China. After 90 consecutive days of exposure (2 h/day), oxidative stress markers in lung, cellular infiltration and cytokines, chemokine, neurotrophin in bronchoalveolar lavage fluid (BALF), and immunoglobulin (Ig) in serum were examined. VOCs exposure could increase significantly reactive oxygen species (ROS) in lung, the levels of interleukin-8 (IL-8), IL-4, eotaxin, nerve growth factor (NGF), and various types of leukocytes in BALF, IgE concentration in serum. In contrast, GSH to GSSG ratio and interferon-gamma were significantly decreased following the VOCs exposure. These results indicate that the VOCs mixture-induced inflammatory response is at least partly caused by release of the ROS and mediators from the activated eosinophils, neutrophils, alveolar macrophages and epithelial cells.

Potent anti-inflammatory activity of ursolic acid, a triterpenoid antioxidant, is mediated through suppression of NF-κB, AP-1 and NF-AT

BACKGROUND

Ursolic acid (UA), a pentacyclic triterpenoid carboxylic acid, is the major component of many plants including apples, basil, cranberries, peppermint, rosemary, oregano and prunes and has been reported to possess antioxidant and anti-tumor properties. These properties of UA have been attributed to its ability to suppress NF-κB (nuclear factor kappa B) activation. Since NF-κB, in co-ordination with NF-AT (nuclear factor of activated T cells) and AP-1(activator protein-1), is known to regulate inflammatory genes, we hypothesized that UA might exhibit potent anti-inflammatory effects.

METHODOLOGY/PRINCIPAL FINDINGS

The anti-inflammatory effects of UA were assessed in activated T cells, B cells and macrophages. Effects of UA on ERK, JNK, NF-κB, AP-1 and NF-AT were studied to elucidate its mechanism of action. In vivo efficacy of UA was studied using mouse model of graft-versus-host disease. UA inhibited activation, proliferation and cytokine secretion in T cells, B cells and macrophages. UA inhibited mitogen-induced up-regulation of activation markers and co-stimulatory molecules in T and B cells. It inhibited mitogen-induced phosphorylation of ERK and JNK and suppressed the activation of immunoregulatory transcription factors NF-κB, NF-AT and AP-1 in lymphocytes. Treatment of cells with UA prior to allogenic transplantation significantly delayed induction of acute graft-versus-host disease in mice and also significantly reduced the serum levels of pro-inflammatory cytokines IL-6 and IFN-γ. UA treatment inhibited T cell activation even when added post-mitogenic stimulation demonstrating its therapeutic utility as an anti-inflammatory agent.

CONCLUSIONS/SIGNIFICANCE

The present study describes the detailed mechanism of anti-inflammatory activity of UA. Further, UA may find application in the treatment of inflammatory disorders.

Intradermal cytosine-phosphate-guanosine treatment reduces lung inflammation but induces IFN-γ-mediated airway hyperreactivity in a murine model of natural rubber latex allergy

Asthma and other allergic diseases are continuously increasing, causing considerable economic and sociologic burden to society. The hygiene hypothesis proposes that lack of microbial T helper (Th) 1-like stimulation during early childhood leads to increased Th2-driven allergic disorders later in life. Immunostimulatory cytosine-phosphate-guanosine (CpG)-oligodeoxynucleotide motifs are candidate molecules for immunotherapeutic studies, as they have been shown to shift the Th2 response toward the Th1 direction and reduce allergic symptoms. Using natural rubber latex (NRL)-induced murine model of asthma, we demonstrated that intradermal CpG administration with allergen reduced pulmonary eosinophilia, mucus production, and Th2-type cytokines, but unexpectedly induced airway hyperreactivity (AHR) to inhaled methacholine, one of the hallmarks of asthma. We found that induction in AHR was dependent on STAT4, but independent of STAT6 signaling. CpG treatment increased production of IFN-γ in the airways and shifted the ratio of CD4(+):CD8(+) T cells toward CD8(+) dominance. By blocking soluble IFN-γ with neutralizing antibody, AHR diminished and the CD4(+):CD8(+) ratio returned to CD4(+) dominance. These results indicate that increased production of IFN-γ in the lungs may lead to severe side effects, such as enhancement of bronchial hyperreactivity to inhaled allergen. This finding should be taken into consideration when planning prophylaxis treatment of asthma with intradermal CpG injections.

Current status and challenges of cytokine pharmacology

The major concern of pharmacology about cytokines has originated from plentiful data showing association between gross changes in their production and pathophysiological processes. Despite the enigmatic role of cytokines in diseases, a number of them have become a subject of cytokine and anti-cytokine immunotherapies. Production of cytokines can be influenced by many endogenous and exogenous stimuli including drugs. Cells of the immune system, such as macrophages and lymphocytes, are richly endowed with receptors for the mediators of physiological functions, such as biogenic amines, adenosine, prostanoids, steroids, etc. Drugs, agonists or antagonists of these receptors can directly or indirectly up- and down-regulate secretion of cytokines and expression of cytokine receptors. Vice versa, cytokines interfere with drug pharmacokinetics and pharmacodynamics through the interactions with cytochrome P450 and multiple drug resistance proteins. The aim of the review is to encourage more intensive studies in these fields of cytokine pharmacology. It also outlines major areas of searching promising candidates for immunotherapeutic interventions.

Thymic stromal lymphopoietin: a new cytokine in asthma

Airway epithelial cells provide mechanical and immune protection against pathogens and allergens. Following activation, these cells produce a wide range of cytokines including thymic stromal lymphopoietin (TSLP). Recently it was established that a high level of TSLP is associated with asthma in mice and in humans. These findings suggest that interfering with the ability of cells to respond to TSLP might prevent the development of airway inflammation. Our review presents current knowledge on mediators that induce TSLP production and on the actions of TSLP on different populations of cells that are related to airway inflammation. TSLP affects dendritic cells, T cells, NKT cells, and mast cells, indicative of the broad role of TSLP in the regulation of inflammatory/allergic processes.

Establishment of an in vitro test system to evaluate the down-regulatory activities of natural products on IL-4

Interleukin-4 (IL-4), a representative TH2 cytokine, plays a pathologic role in the onset of various allergic diseases including atopic dermatitis, atopic rhinitis, and asthma. Several drug candidates that down-regulate IL-4 expression have been studied for their possible use as antiallergic agents in clinical settings. Therefore, an in vitro test to evaluate IL-4 promoter activities might be useful for selecting candidates of novel natural therapeutics. The promoter region (-741 to +56) of IL-4 was cloned upstream of a luciferase gene in the plasmid pGL4.14 with a hygromycin resistance gene as a selection marker to generate pGL4.14-IL-4. Treatment with PMA and A23187 highly increased luciferase activity by approximately 10-fold compared with the control in both EL-4 thymoma and RBL-2H3 cells transiently transfected with pGL4.14-IL-4, as well as in stable cell lines constantly expressing pGL4.14-IL-4. Cyclosporin A and dexamethasone, well-known anti-allergic agents, significantly down-regulated the activity in a dose-dependent manner. The feasibility of this system was evaluated by measuring the down-regulatory activities of various extracts from the TBRC plant library on PMA- and A23187-induced luciferase activities of IL-4 promoter, and by measuring IL-4 production in cultured cells using ELISA assays. The results of this study suggest that this primary screening system is simple and time-saving, and might be suitable for the selection of natural therapeutic candidates for allergic disease by measuring the down-regulatory effects of natural products on the IL-4 promoter.

Formaldehyde exposure induces airway inflammation by increasing eosinophil infiltrations through the regulation of reactive oxygen species production

Formaldehyde (FA) is a well-known cytotoxic irritant to the airways, but the mechanism of airway inflammation due to FA has not been clarified. In the present study, C57BL/6 mice were exposed to two concentrations (5 and 10ppm) of FA for 6h/day, 5days/week, for 2 weeks. The FA-exposed mice had much higher number of CCR3(+) eosinophils than control mice, and showed upregulated gene expression of CC-chemokine receptor-3 (CCR3), eotaxin and intercellular adhesion molecules-1 (ICAM-1) as well as an increased expression of proinflammatory and Th2 cytokines, such as interleukin (IL)-1β, IL-4 and IL-5. In addition, FA exposure revealed a considerable increase in the serum levels of IgG1, IgG3, IgA and IgE compared to controls. Histopathological analysis of the lung tissues demonstrated eosinophils and mononuclear cell infiltration of the alveolar cell walls and alveolar spaces. Gene expression of thioredoxin (TRX), redox-regulating antioxidant proteins, was markedly suppressed in FA-exposed mice, and thereby intracellular ROS levels were increased along with increased FA concentration. These results were consistent with an increase in the number of CCR3-expressing eosinophils, and indicate that FA-induced ROS was generated from eosinophils recruited to the inflammatory sites of the airways.

Cry-consensus peptide, a novel peptide for immunotherapy of Japanese cedar pollinosis, induces Th1-predominant response in Cry j 1-sensitized B10.S mice

Cry-consensus peptide (CCP) is a newly designed peptide for peptide-based immunotherapy of Japanese cedar pollinosis but its mechanism of efficacy is unknown. We investigated the effect of CCP on Cry j 1-specific Th1/Th2 response in a mice model. Subcutaneous injection of CCP decreased Cry j 1-specific IgE and IgG1 in blood slightly, but the IgG2a level was increased significantly in a dose dependent manner. Splenocytes from these mice were stimulated with Cry j 1 in vitro. This inhibited IL-4, IL-5 and IL-10 secretion significantly, but IFN-gamma secretion was increased. In vitro CCP stimulation of splenocytes from Cry j 1-sensitized mice induced more marked Th1-predominancy of cytokine production than native allergen stimulation. Taken together, these data suggest that one of the mechanisms of CCP is dependent on the modulation of the antigen-specific Th1/Th2 response.

Inhibition of IL-4/IL-13 does not enhance the efficacy of allergen immunotherapy in murine allergic airway inflammation

BACKGROUND

Successful allergen-specific immunotherapy (SIT) is associated with reduced Th2 cytokine production and the induction of IL-10-producing regulatory T cells. To improve treatment efficacy, we investigated the impact of an IL-4/IL-13 inhibitor during SIT.

METHODS

BALB/c mice were sensitized intranasally with ovalbumin (OVA) for 4 weeks. Subsequently, they were subjected to intranasal SIT, with OVA being administered at doses increasing from 1 mug to 1 mg over 3 weeks with or without an IL-4/IL-13 inhibitor. Serum OVA-specific antibodies were measured and bronchoalveolar lavage (BAL) fluids were checked for airway eosinophilia. Subsequently, lung tissue was examined histologically for inflammatory infiltrates. Cytokines were detected in BAL fluids and spleen cell cultures. Furthermore, CD4 CD25 double-positive spleen T cells were checked for intracellular IL-10 production by flow cytometry.

RESULTS

OVA sensitization resulted in persistent IgE synthesis and an eosinophil-rich allergic airway inflammation combined with increased IL-4 and IL-5 levels. Therefore, intranasal SIT could efficiently reverse the allergic phenotype. This was associated with decreased IL-4 and IL-5 levels, and increased IL-10 levels in BAL fluids as well as increased amounts of IL-10-producing CD25+ regulatory T cells. However, mice treated with the IL-4/IL-13 inhibitor during SIT did not produce significantly different results .

CONCLUSION

The use of an IL-4/IL-13 inhibitor as an adjuvant for SIT did not enhance anti-allergic effects. Thus, the observed reversal of Th2 responses during SIT may not be the keystone for successful therapy, but rather other factors, e.g. IL-10-producing regulatory T cells, may be crucial.

Attenuated Salmonella typhimurium reduces ovalbumin-induced airway inflammation and T-helper type 2 responses in mice

Cytokines produced by Th2 cells are responsible for the pathogenesis of asthma. Th1-biased immune responses caused by attenuated salmonella have the potential to relieve asthmatic symptoms. We evaluated whether oral administration of attenuated salmonella could modulate allergic responses in a chicken ovalbumin (OVA)-induced asthmatic murine model. Mice were fed with attenuated salmonella SL7207 one dose before and three doses during the induction of an allergic response. Lung histology, percentages of eosinophil in bronchoalveolar lavage fluid, serum levels of OVA-specific antibodies and cytokine production by OVA-activated splenocytes were evaluated in mice with or without the administration of SL7207. A significant reduction in pulmonary eosinophilic infiltration was observed in mice receiving attenuated salmonella. Lower levels of OVA-specific IgG1 but higher titres of OVA-IgG2a in serum were also detected in this group. Splenocytes from salmonella-fed mice produced lower levels of Th2 cytokines upon OVA stimulation. The administration of attenuated salmonella significantly suppressed immunopathological symptoms in OVA-sensitized mice. Inhibition of Th2 responses might explain the potential mechanisms. This study provides some evidence for the feasibility of attenuated salmonella as an effective vaccine for allergic diseases.

Protective effect of the DNA vaccine encoding the major house dust mite allergens on allergic inflammation in the murine model of house dust mite allergy

Background

Vaccination with naked DNA encoding antigen induces cellular and humoral immunity characterized by the activation of specific Th1 cells.

Objective

To evaluate the effects of vaccination with mixed naked DNA plasmids encoding Der p 1, Der p 2, Der p 3, Der f 1, Der f 2, and Der f 3, the major house dust mite allergens on the allergic inflammation to the whole house dust mites (HDM) crude extract.

Methods

Three hundred micrograms of these gene mixtures were injected into muscle of BALB/c mice. Control mice were injected with the pcDNA 3.1 blank vector. After 3 weeks, the mice were actively sensitized and inhaled with the whole house dust mite extract intranasally.

Results

The vaccinated mice showed a significantly decreased synthesis of total and HDM-specific IgE compared with controls. Analysis of the cytokine profile of lymphocytes after challenge with HDM crude extract revealed that mRNA expression of interferon-γ was higher in the vaccinated mice than in the controls. Reduced infiltration of inflammatory cells and the prominent infiltration of CD8+ T cells were observed in histology of lung tissue from the vaccinated mice.

Conclusion

Vaccination with DNA encoding the major house dust mite allergens provides a promising approach for treating allergic responses to whole house dust mite allergens.

Crystal structure and some properties of a major house dust mite allergen, Derf 2

Pyroglyphid house dust mites are a major source of allergens in house dust. Mite allergens sensitize and induce asthma, rhinitis, and eczema in a large portion of patients with allergic diseases. Here, the crystal structure of a major mite allergen, Derf 2, derived from Dermatophagoides farinae was solved by single isomorphous replacement method with anomalous scattering (SIRAS) at 2.1A resolution. The present study also demonstrated that the conformation of the allergen was critical in the determination of Th1/Th2 shift based on physicochemical and immunological analyses. This indicates that rigidly folded and singly dispersed structure is essentially required for the generation of Th2 type cells by the allergen, while conformational variant protein leads to Th1 skewing, irrespective of the same amino acid sequence. This structure/function relationship may allow us to develop a novel strategy for hyposensitization therapy in patients with allergic diseases triggered by house dust mite allergens.

Rocaglamide derivatives are immunosuppressive phytochemicals that target NF-AT activity in T cells

Aglaia (family Meliaceae) plants are used in traditional medicine (e.g., in Vietnam) for the treatment of inflammatory skin diseases and allergic inflammatory disorders such as asthma. Inflammatory diseases arise from inappropriate activation of the immune system, leading to abnormal expression of genes encoding inflammatory cytokines and tissue-destructive enzymes. The active compounds isolated from these plants are derivatives of rocaglamide. In this study we show that rocaglamides are potent immunosuppressive phytochemicals that suppress IFN-gamma, TNF-alpha, IL-2, and IL-4 production in peripheral blood T cells at nanomolar concentrations. We demonstrate that rocaglamides inhibit cytokine gene expression at the transcriptional level. At the doses that inhibit cytokine production, they selectively block NF-AT activity without impairing NF-kappaB and AP-1. We also show that inhibition of NF-AT activation by rocaglamide is mediated by strong activation of JNK and p38 kinases. Our study suggests that rocaglamide derivatives may serve as a new source of NF-AT-specific inhibitors for the treatment of certain inflammatory diseases.

CpG ODNs treatments of HIV-1 infected patients may cause the decline of transmission in high risk populations - a review, hypothesis and implications

The Joint United Nations Program on HIV-1/AIDS (UNAIDS) announced its goal to stop HIV-1 transmission by antiviral (HAART) treatment of patients since at the end of 2003 the number of people living with HIV-1 was 38 million, 25 million in the sub-Saharan region of Africa. The present review deals with a new approach to simultaneously treat HIV-1/AIDS patients in HIV-1 endemic regions with CpG oligodeoxynucleotides (ODNs) and people at high risk of infection with a vaccine containing CpG ODNs combined with synthetic HIV-1 peptides by intranasal and intradermal applications. During HIV-1 infection a gradual increase in the levels of IL-4 and IgE in the patients' serum, was reported. It was suggested that such an increase of the cytokine IL-4 and the IgE immunoglobulin are interconnected and may serve as indicators for the coming stage of AIDS. It was also suggested that the IL-4 and IgE increase in the serum of HIV-1 infected people resemble the increase of IL-4 and IgE levels in allergic patients that were exposed to endogenous or environmental allergens [Becker, Virus Genes 28, 5--18, 2004]. Indeed, it was reported that the HIV-1 virions' shed gp120 molecules, which contain a superantigen (superallergen) domain that enables the viral glycoprotein to bind the V(H)3 domain of IgE molecules that are bound to FcepsilonRI+ hematopoietic cells [basophils, mast cells, dendritic cells (DCs) and plasmacytoid DCs (pDCs)]. Such interaction was reported to induce the hematopoietic cells to release large amounts of Th2 cytokines IL-4, IL-5, IL-10 and IL-13. These findings led to the hypothesis [Op. cit.] that the cure of HIV-1/AIDS patients requires the induction of endogenous synthesis of type I interferons (INF alpha and beta) with a bacterial CpG rich DNA that will induce the patients' pDCs to release large amounts of type I IFNs. Under these conditions HIV-1 replication in polarized to Th2 cells is inhibited. Type I IFNs reactivate the patients' inhibited Th1 cells to synthesize IL-2 and IL-12 cytokines that activate the maturation of CTL precursors. The unmethylated bacterial DNA activates B synthesis to switch to IgG and IgA synthesis. The novel drug CpG ODNs is being tested for the prevention and the treatment of allergic humans and in the experimental system of allergic mice. It was also reported that treatment of mice with CpG ODN prior to or after retrovirus infections protected and cured, respectively, the retrovirus infection. It was also reported that CpG ODNs treatments of mice exposed to allergen protected them against the development of the allergic response. Phase I treatment of healthy people with CpG ODNs provided information on the safety of these compounds. The CpG ODNs A and B bind to Toll like receptors that are present in pDCs and B cells, respectively, CpG ODN - A is the ligand for TLR9+ pDCs and induce the release of large amounts of IFN-alpha, beta. CpG ODN-B is the ligand for TLR9+ in B cells and induce the synthesis of IgG and IgA. CpG ODN-C contains motifs from CpG ODNs A and B and is more active. The present review is based on findings from studies that reported that CpG ODNs treatment of retrovirus infected mice, monkeys and allergic mice prevented the virus and allergens caused diseases, respectively. Based on these studies, a hypothesis is presented that treatment of HIV-1 infected and AIDS patients with CpG ODN-A and B or CpG ODN-C have the potential to inhibit IL-4 synthesis and release from FcrepsilonRI+ hematopoietic cells by inducing TLR9+ pDCs to release large amounts of type I IFNs. TLR9+ B cells are induced by CpG ODN-B to switch from IgE to IgG, IgA synthesis. In addition, type I IFNs (alpha, beta) have the capacity to inhibit HIV-1 replication in polarized Th2 cells. Type I IFNs reactivate the patients' Th1 cells to synthesize IL-2 and IL-12 cytokines, activators of the precursor cytotoxic T cells (CTLs), leading to the reactivation of the inhibited adaptive immune response. Antiviral CTLs have the ability to clear the virus infection. The present novel approach to the treatment and of HIV-1/AIDS patients with CpG ODNs may prevent HIV-1 transmission and the AIDS pandemic if controlled studies on the treatments with CpG ODNs of HIV-1 infected people will be done by international and private agencies and companies to define the effective treatment regime and the efficacy of the treatments to HIV-1 infected people at different times post-infection. It is also hypothesized that in order to stop HIV-1 transmission in HIV-1 endemic regions the people at high risk of HIV-1 infection should be treated at the same time as HIV-1 infected people with a vaccine containing synthetic CpG-ODNs combined with synthetic HIV-1 peptides, compatible with the major HLA haplotypes of the regional population. The vaccine may be self-applied by people at high risk of infection by the intra-nasal route and by intra-dermal application as a "peplotion vaccine". The stimulation of the antiviral CTL response by HIV-1 infected people and the active antiviral immune response in the vaccinated population may lead to a decline in HIV-1 transmission and may be a model for control of the HIV-1/AIDS pandemic.

Allergen-specific immunosuppression by ovalbumin fused with diphtheria toxin in mice sensitized with albumins of different origin

BACKGROUND

We previously reported that ovalbumin-diphtheria toxin (OVA-DT) fusion protein eliminates mast cells bearing OVA-specific IgE and protects OVA-sensitized mice from fatal anaphylaxis induced by OVA challenge.

OBJECTIVE

To prove the specificity of therapeutic effect of OVA-DT to allergy induced by OVA only and not by other allergens such as human serum albumin (HSA), and to examine the cytotoxic effect of OVA-DT on B cells bearing OVA-specific IgE.

METHODS

Mice were sensitized with two different antigens, OVA and HSA, and then treated with OVA-DT. The therapeutic effect of OVA-DT on the allergy response to each of allergen was evaluated by anaphylactic test. The effect of OVA-DT on the production of allergen-specific Ig isotypes of the sensitized mice and the cytotoxic effect of OVA-DT on B cells expressing OVA-specific IgE were examined.

RESULTS

OVA-DT suppressed only OVA-induced allergy but not HSA-induced allergy in mice sensitized with a mixture of OVA and HSA. The suppression was prolonged even to the mice boosted with the same allergen 14 days after last treatment of OVA-DT. In addition, when the sensitized mice were boosted with the same allergens 14 days after last treatment of OVA-DT, the mice showed to increase the production of OVA-specific IgG2a/IgG3 and decreased that of OVA-specific IgE. OVA-DT targeted B cells bearing OVA-specific IgE, and killed them by DT-mediated cytotoxicity.

CONCLUSION

The therapeutic effect of OVA-DT was specific to OVA-induced allergy and the suppression of OVA-induced allergy was continuously shown in the mice boosted with the same allergens. This is considered to be caused by the increase of OVA-specific IgG2a and IgG3, and because of the decrease of OVA-specific IgE by killing of B cells bearing OVA-specific IgE.

Effect of the water-soluble and non-dialyzable fraction isolated from Senso (Chan Su) on lymphocyte proliferation and natural killer activity in C3H mice

We found lymphocyte proliferating substances in the water-soluble and non-dialyzable fraction prepared from the crude drug Senso (Chan Su). The effect of this fraction was increased by affinity chromatography using the concanavalin A-agarose. By analyzing the fraction using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and lectin blotting, we estimated that one of the active substances of this fraction is a glycoprotein that has about 13 kDa of molecular weight and D-mannose within the molecule. The purified fraction increased the IL-2 and the IL-12 level in the supernatant of spleen cell culture, and increased the natural killer activity of spleen lymphocyte in C3H/HeN mice. These results show that Senso contains immunopotentiating substances that may serve as an immunomodulator in an organism.

A novel adjuvant-allergen complex, CBP-rFel d 1, induces up-regulation of CD86 expression and enhances cytokine release by human dendritic cells in vitro

Allergen-specific immunotherapy is commonly performed with allergen extracts adsorbed to aluminium hydroxide (alum). The undesirable effects associated with the use of alum, including granuloma formation at the site of injection and stimulation of T helper 2 (Th2) cytokine production, has generated interest in alternative allergen carriers, one being carbohydrate-based particles (CBPs). Here, we have investigated the in vitro effects of the recombinant major cat allergen Fel d 1 (rFel d 1) coupled to CBPs (CBP-rFel d 1) on human monocyte-derived dendritic cells (MDDCs) obtained from healthy blood donors. A majority of the CD1a(+) MDDCs internalized fluorescein isothiocyanate-labelled CBP-rFel d 1, as demonstrated by flow cytometry and confocal laser-scanning microscopy. Furthermore, an up-regulation of the expression of the costimulatory molecule, CD86, on the MDDCs was induced by CBP-rFel d 1, but not by rFel d 1 or CBPs alone. Finally, three- and fourfold increases in the release of interleukin-8 and tumour necrosis factor-alpha, respectively, were observed when MDDCs were cultured in the presence of CBP-rFel d 1. Altogether, our results indicate that the use of CBPs as an allergen carrier and adjuvant is a promising candidate for the improvement of allergen-specific immunotherapy.

TH1 and TH2 lymphocyte development and regulation of TH cell-mediated immune responses of the skin

Since the first description of the subpopulations of TH1 and TH2 cells, insights into the development and control of these cells as two polarized and physiologically balanced subsets have been generated. In particular, implications of the TH1-TH2 concept for TH cell-mediated skin disorders have been discovered. This article will review the basic factors that control the development of TH1 and TH2 cells, such as the cytokines IL-12 and IL-4 and transcription factors, the possible role of costimulatory molecules, and specialized dendritic cell populations. These regulatory mechanisms will be discussed in the context of polarized TH1 or TH2 skin disorders such as psoriasis and atopic dermatitis. Also presented are the principles that govern how chemokines and chemokine receptors recruit TH1 and TH2 cells to inflammatory sites and how they amplify these polarized TH cell responses. All of these concepts, including a novel role for IL-4-inducing TH1 responses, can contribute to the design of better therapeutic strategies to modulate TH cell-mediated immune responses.

The role of interleukin 10 in the pathogenesis and potential treatment of skin diseases

Interleukin 10 (IL-10) is a key cytokine produced by a multitude of immune effector cells and possesses distinct regulatory effects on immune functioning in the skin. In this article we report the current understanding of the immunobiology of IL-10 and identify the role of IL-10 in cutaneous infection as well as in autoimmune and neoplastic processes. We reviewed the literature to examine the function of IL-10 in different cutaneous disorders. IL-10 can influence and potentially treat T1/T2 differentiation, antigen-presenting cell functioning, antigen-presenting cell-mediated T-cell activation, and T-cell, B-cell, and mast cell growth and differentiation that is aberrant in various disease processes. The literature consensus is that the multitude of effects of IL-10 contribute to the pathogenesis of different skin disorders. In certain circumstances IL-10 could represent novel therapeutic approaches to treating cutaneous diseases.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be acquainted with the role of IL-10 in many infectious diseases, autoimmune skin disease, inflammatory processes, and malignancy. Its possible role in the resolution of various skin diseases should be better understood.

Immunomodulation and immunodeficiency

This article briefly reviews the concepts of immunodeficiency and immunomodulation as they relate to selected skin diseases in the dog and cat. Immunodeficiency states are uncommon and may be associated with a subnormal or down-regulated immune system, including humoral deficiencies, such as IgA, and abnormal lymphocyte or neutrophil function. Establishing a causal relationship between a skin disease and presumed immunodeficient state has been difficult due to the rarity of such conditions, and the limited nature of the techniques used to characterise the immune system response. Severe combined immunodeficiency in dogs is a well characterised primary immunodeficiency state involving lymphocytes; retrovirus infection in cats may lead to an acquired immunodeficient state with some association with certain dermatological conditions although it remains unclear that infection is causally linked with disease. Immunomodulation usually implies stimulating the immune system along a beneficial pathway. Such a therapeutic approach may involve a wide variety of agents, for example intravenous immunoglobulin. There are few randomised controlled trials with veterinary patients that unequivocally demonstrate beneficial responses to immunomodulatory agents. Interferons are cytokines of major interest in human and veterinary medicine for their antiviral, anti-tumour and immunomodulatory effects. The advent of veterinary-licensed products containing recombinant interferon may enable demonstration of the efficacy of interferons for conditions such as canine papillomatosis and feline eosinophilic granuloma complex. Canine pyoderma has been treated with a number of presumed immunomodulatory agents with limited success. With more detailed knowledge of the pathogenesis of pyoderma it may be possible to develop efficacious immunomodulators.

Viral-induced T helper type 1 responses enhance allergic disease by effects on lung dendritic cells

It is widely accepted that T helper type 1 (T(H)1) cytokines such as interferon-gamma (IFN-gamma) antagonize allergic diseases mediated by T(H)2 cytokines. The 'hygiene hypothesis' has also proposed that decreased childhood exposure to pathogen-derived T(H)1 cytokines may underlie the recent increased prevalence of asthma, a T(H)2-mediated disease. We show here that influenza A viral infection, which induces large amounts of intrapulmonary IFN-gamma production, unexpectedly enhanced later allergen-specific asthma and promoted dual allergen-specific T(H)1 and T(H)2 responses. Pulmonary dendritic cells obtained from the lung after viral clearance and resolution of acute inflammation conferred enhanced allergic disease and concurrent T(H)1 and T(H)2 immune responses, and these effects were dependent on IFN-gamma secreted during the acute viral infection. Thus, respiratory viral infection and the acute T(H)1 response can positively regulate T(H)2-dependent allergic pulmonary disease in vivo, at least in part, by altering pulmonary dendritic cell function.

Lymphotoxin is required for maintaining physiological levels of serum IgE that minimizes Th1-mediated airway inflammation

Although elevated levels of IgE in asthmatic patients are strongly associated with lung infiltration by activated T helper (Th) 2 cells, the physiological role of immunoglobulin E (IgE) in the airway remains largely undefined. Lymphotoxin-deficient α (LTα^−/−) mice exhibit increased airway inflammation, paradoxically accompanied by diminished levels of IgE and reduced airway hyperresponsiveness in response to both environmental and induced antigen challenge. The severe lung inflammation in LTα^−/− mice is Th1 in nature and can be alleviated by IgE reconstitution. Conversely, depletion of IgE in wild-type mice recapitulates the lung pathologies of LTα^−/− mice. Therefore, this work has revealed that lymphotoxin is essential for IgE production, and a physiological role of IgE in the airway may consist of maintaining the balance of Th1 and Th2 responses to prevent aberrant inflammation.

Regulation of IL4 gene expression by T cells and therapeutic perspectives

Interleukin-4 (IL-4) is crucial for the differentiation of naive T helper (T(H)) cells into the T(H)2 effector cells that promote humoral (antibody) immunity and provide protection against intestinal helminths. IL-4 also has a central role in the pathogenesis of allergic inflammation. Many transcription factors are involved in the regulation of expression of the gene encoding IL-4. Initiation of transcription of the gene encoding IL-4 in naive T(H) cells is regulated by the T(H)2-specific transcription factor GATA3, whereas acute expression of the gene encoding IL-4 in T(H)2 cells is mediated by inducible, ubiquitous transcription factors after antigen encounter. This review focuses on acute activation of the gene encoding IL-4 in T cells and discusses therapeutic perspectives at the transcriptional level.

Chemokines: roles in leukocyte development, trafficking, and effector function

Chemokines, representing a large superfamily of 8- to 15-kd proteins, were originally discovered through their ability to recruit various cell types into sites of inflammation. It is now clear that these molecules play a much wider role in immune homeostasis, playing key roles in driving the maturation, homing, and activation of leukocytes. In this review we analyze the roles chemokines play in the development, recruitment, and activation of leukocytes. Because signaling from the receptors drives these processes, signal transduction from chemokine receptors will also be reviewed. Taken together, we highlight the various points at which chemokines contribute to allergic inflammation and at which their targeting might contribute to new therapies for type I hypersensitivity reactions.