Immune dysregulation in allergic respiratory disease: the role of T regulatory cells

Distinct T helper cell-mediated antitumor immunity: T helper 2 cells in focus

The adaptive arm of the immune system is crucial for appropriate antitumor immune responses. It is generally accepted that clusters of differentiation 4+ (CD4+) T cells, which mediate T helper (Th) 1 immunity (type 1 immunity), are the primary Th cell subtype associated with tumor elimination. In this review, we discuss evidence showing that antitumor immunity and better prognosis can be associated with distinct Th cell subtypes in experimental mouse models and humans, with a focus on Th2 cells. The aim of this review is to provide an overview and understanding of the mechanisms associated with different tumor outcomes in the face of immune responses by focusing on the (1) site of tumor development, (2) tumor properties (i. e., tumor metabolism and cytokine receptor expression), and (3) type of immune response that the tumor initially escaped. Therefore, we discuss how low-tolerance organs, such as lungs and brains, might benefit from a less tissue-destructive immune response mediated by Th2 cells. In addition, Th2 cells antitumor effects can be independent of CD8+ T cells, which would circumvent some of the immune escape mechanisms that tumor cells possess, like low expression of major histocompatibility-I (MHC-I). Finally, this review aims to stimulate further studies on the role of Th2 cells in antitumor immunity and briefly discusses emerging treatment options.

Recent discovery of phosphoinositide 3-kinase γ inhibitors for the treatment of immune diseases and cancers

Recently, PI3Kγ, a vital kinase, which involved in numerous intracellular signaling pathways, has been considered as a promising drug target for the treatment of immune diseases and certain cancers. Before the 21st century, few selective PI3Kγ inhibitors were discovered because no non-conserved structure in the ATP binding sites of PI3Kγ had been found. Since the discovery of the non-ATP binding pocket, the reported structures of potent and selective PI3Kγ inhibitors have become more diverse, and one compound (IPI549) has entered Phase I clinical trial. This review centers on a general overview of PI3Kγ inhibitors in clinical and preclinical as well as further therapeutic applications in human diseases.

In vitro nasal mucosa gland-like structure formation on a chip

The emergence of microfluidic epithelial models using diverse types of cells within a physiologically relevant microenvironment has the potential to be a powerful tool for preclinical drug screening and pathophysiological studies. However, to date, few studies have reported the development of a complicated in vitro human nasal epithelial model. The aim of this study was to produce an in vitro human nasal mucosa model for reliable drug screening and clinical applications. Here, we integrated and optimized several culture conditions such as cell type, airway culture conditions, and hydrogel scaffolds into a microfluidic chip to construct an advanced in vitro human nasal mucosa model. We observed that the inducing factors for nasal gland-like structures were secreted from activated human dermal microvascular endothelial cells. Furthermore, our in vitro nasal mucosa presented different appearance and characteristics under hypoxic conditions. Morphological and functional similarities between in vivo nasal mucosa and our model indicated its utilization as a reliable research model for nasal diseases including allergic rhinitis, chronic sinusitis, and nasal polyposis.

Changes of CD4(+) CD25(+) Regulatory T Cells, FoxP3 in Adjuvant Arthritis Rats with Damage of Pulmonary Function and Effects of Tripterygium Glycosides Tablet

Objective. To observe the effects of tripterygium glycosides tablet (TPT) on swelling degree, arthritis index (AI), pulmonary function, cytokines, the expression of regulatory T cells (Treg), and Foxp3 in rats of adjuvant arthritis. Methods. Rats were averagely divided into normal control (NC) group, model control (MC) group, methotrexate (MTX) group, and tripterygium glycosides tablet (TPT) group. Except for the rats of normal group, the others were intracutaneously injected with 0.1 mL of Freund's complete adjuvant in the right hindlimb. NC group and MC group were treated with physiological saline. MTX group and TPT group were treated with MTX, TPT, respectively. Results. The levels of swelling degree, AI, the alveolar inflammation integral, TNF alpha (TNF-α), and endothelium-1 (ET-1 ) in MC group were significantly increased (P < 0.01), and the levels of forced vital capacity (FVC), 25% vital capacity of the peak expiratory flow (FEF(25)), 50% vital capacity of the peak expiratory flow (FEF(50)), 75% vital capacity of the peak expiratory flow (FEF(75)), maximum midexpiratory flow (MMF), peak expiratory flow (PEF), interleukin-10 (IL-10), CD4(+) CD25(+) Treg, and Foxp3 were decreased (P < 0.01). The scores of alveolitis and ET-1 were decreased with treatment of TPT. The levels of FVC, FEF(25), FEF(50), FEF(75), MMF, PEF, IL-10, and CD4(+) CD25(+) Treg in peripheral blood were increased. The expressions of Foxp3 protein and mRNA in lung tissue were also increased in TPT group. Conclusions. The paw swelling can be inhibited by TPT, and the inflammatory response in lung tissue was also decreased, which is a significant improvement in pulmonary function. The mechanism is probably associated with upregulating the expression of IL-10, Foxp3, and downregulating the level of TNF-α.

CD4+CD25(high) Treg cells in peripheral blood during remission and exacerbation of allergic asthma in children

AIM

To determine the percentage of CD4+CD25(high) Treg cells in peripheral bloodCD4+ T cells of allergic asthmatic children during disease remission and exacerbation.

METHODS

Peripheral blood mononuclear cells (PBMC) and serum samples were collected from 6- to 11-year-old children with mild-to-moderate allergic asthma (n = 34)and from healthy controls (n = 15). CD4+CD25(high) T cells in PBMC were detected by flow cytometry. Total and specific IgE in serum were analysed by enzyme-amplified chemiluminescence, and IL-2 was measured by ELISA.

RESULTS

There was no significant difference in CD4+CD25(high) T-cell proportions between asthmatic children in exacerbation and remission as compared with controls.CD4+CD25(high) T-cell percentages were not correlated with total and specific IgE. IL-2 was elevated in both disease remission and exacerbation but did not correlate significantly with CD4+CD25(high) T-cell percentages.

CONCLUSION

CD4+CD25(high) T-cell proportion in the peripheral blood of total CD4+T cells is not reduced in children with allergic IgE-mediated asthma and does not differ between disease remission and exacerbation.

Effects of repeated intratracheally administered lipopolysaccharide on primary and secondary specific antibody responses and on body weight gain of broilers

Earlier, we reported that pathogen-associated molecular patterns such as lipopolysaccharide (LPS), when administered intratracheally (i.t.), affected primary and secondary specific antibody responses to antigens administered concurrently, either i.t. or systemically, and also affected BW gain (BWG) of layers and broilers. In the present study, we evaluated the effects of repeated i.t. challenge with LPS concurrently with or before i.t. immunizations with the specific antigens human serum albumin (HuSA) and rabbit gamma globulin (RGG) on primary (HuSA, RGG) and secondary (HuSA) systemic antibody responses and (isotype) IgM and IgG responses at 2 different ages. Broilers were challenged via the trachea at 3 and 7 wk of age with various combinations of LPS, HuSA, and RGG. All treatments affected immune responses at several time points and also affected BWG, albeit temporarily for the latter. Lipopolysaccharide enhanced primary antibody responses to HuSA and to RGG, when challenged concurrently, but birds challenged solely with LPS at 3 wk of age also showed enhanced primary antibody responses to HuSA and RGG given at 7 wk of age. This was true for IgM as well as IgG isotype responses. Lipopolysaccharide challenge negatively affected BWG at 3 wk of age, whereas the negative effects of LPS after a secondary LPS challenge at 7 wk of age were most pronounced in the birds challenged with LPS at 3 wk of age. The present results indicated that LPS, when administered i.t. at a young age, may affect specific humoral immune responsiveness to antigens administered simultaneously and to BWG of broilers, but also when challenged 4 wk later with specific antigens, suggesting an enhanced status of immune reactivity or sensitivity. The hygienic status of broiler houses at a young age may thus influence BWG, immune responsiveness, and, consequently, the vaccine efficacy and disease resistance in broilers at later ages. The consequences of our findings are discussed.

Pioglitazone attenuates allergic inflammation and induces production of regulatory T lymphocytes

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonists have been shown to be involved in the regulation of allergic inflammatory responses. The molecular mechanisms by which PPAR-gamma activation inhibits the inflammatory process have not been well understood.

METHODS

BALB/c mice received ovalbumin (OVA) sensitization followed by OVA intranasal challenge. Mice in the treatment group received intragastric administration with pioglitazone (PIO; 30 mg/kg) before each OVA challenge. Various allergic responses were then assessed.

RESULTS

The frequencies of sneezing and nose-scratching and eosinophil infiltration decreased significantly in the PIO treatment group compared with the OVA group (p < 0.05). The PIO treatment also showed that the levels of nasal cavity lavage fluid interleukin (IL)-5 and sera OVA-specific immunoglobulin E (IgE) were markedly reduced (p < 0.05). PIO significantly increased the expression of Foxp3 mRNA (p < 0.05) and induced production of regulatory T lymphocyte (p < 0.01) compared with the OVA group.

CONCLUSION

Given the potent effectiveness shown by PIO, we conclude that PPAR-gamma agonists deserve investigation as potential therapies for human allergic upper airway inflammation.

TH1/TH2 balance in concomitant immediate and delayed-type hypersensitivity diseases

In spite of the observation of mutual inhibitory properties of TH1 and TH2 CD4+ cells, a group of patients developed simultaneously immediate and delayed-type hypersensitivity reactions that are theoretically antagonistic. Patients presenting concomitant hypersensitivity reactions were evaluated for cytokine production. PBMC from 45 patients and 13 non-atopic individuals were cultured with mite allergen and mitogen and the supernatants obtained were evaluated for cytokine production by ELISA. The analysis of the cytokines levels revealed increased production of pro-inflammatory cytokine TNF-alpha in the non-atopic individuals after specific and mitogen stimulus. The IL-4 was largely observed on serum samples and IL-5 levels were higher in the double sensitized group (group DerpNi) after PHA stimulus. The IL-13 levels were increased in sensitized groups (Derp and DerpNi groups) after PHA stimuli. Atopic patients (Derp and DerpNi groups) presented lowest levels IFN-gamma and the analysis of TGF-beta production after rDER P I stimulation have shown increased levels among sensitized patients to Dermatophagoides pteronyssinus mite. IL-10 levels did not differ after antigen stimulation but basal production was higher on Derp and DerpNi groups. Furthermore, negative correlations were observed between IFN-gamma levels and IL-4, IL-13 and IL-10. This study has shown patients able to react, concomitantly, to the two types of antigens - rDER P I and NiSO4, present distinct pattern of cytokine production. The increased levels of IL-13 in the sensitive individuals to mite antigen (rDER P I) and IFN-gamma in NiSO4 sensitized individuals confirm the role of the type TH2 response in the atopies and TH1 type in DCA.

Novel vaccination for allergy through gene silencing of CD40 using small interfering RNA

Small interfering RNA (siRNA) is a potent means of inducing gene-specific silencing. Gene silencing strategies using siRNA have demonstrated therapeutic benefits in animal models of various diseases, and are currently in clinical trials. However, the utility of gene silencing as a treatment for allergic diseases has not yet been reported. In this study, we report a novel therapy for allergy through gene silencing of CD40, a critical costimulatory molecule and a key factor in allergic immune responses. Silencing CD40 resulted in generation of immunoregulatory dendritic cells (DCs). Administration of CD40 siRNA remarkably reduced nasal allergic symptoms and local eosinophil accumulation in the OVA-induced allergic mice. The OVA-specific T cell response was inhibited after the CD40 siRNA treatment. Additionally, anti-OVA specific IgE and production of IL-4 and IL-5 of T cells stimulated by OVA were significantly decreased in CD40 siRNA-treated mice. Furthermore, we demonstrated that the therapeutic effects by CD40 siRNA were associated with impaired Ag-presenting functions of DCs and B cells, and generation of regulatory T cells. The present study highlights a therapeutic potential of siRNA-based treatment for allergic diseases.

Long-chain polyunsaturated fatty acids influence the immune system of infants

Several events occur during the first months of life that allow the immune system to become competent and functional. The aim of this article is to review the rationale and evidence of an influence of (n-3) long-chain PUFA (LCPUFA) on the immune system of infants. The (n-3) LCPUFA exert their immunomodulatory activities at different levels. The (n-3) LCPUFA metabolites induce eicosanoid production, alter gene expression, and modify lipid raft composition, altering T-cell signaling; all contribute to immunological functional changes. However, the roles of these mechanisms and the types of T or other immunological cells involved remain unclear at present. Moreover, the effect of (n-3) LCPUFA on the immune system of infants may vary according to dose, time of exposure, and profile of the immune system (T-helper, Th1/Th2). Most of the interventional studies in infancy have been performed for the prevention of allergy. They all confirmed influence on T-cell function and cytokine profiles, but clinically beneficial effects are more conflicting. Supplementation of the maternal diet in pregnancy or early childhood with (n-3) LCPUFA is potentially a noninvasive intervention strategy to prevent the development of allergy, infection, and possibly other immune-mediated diseases. However, any long-term in vivo effects on (n-3) LCPUFA early in life for immunomodulatory defense in infants and later on immune status and health remain to be assessed.

The European LABDEL project and its relevance to the prevention and treatment of allergies

In March 2001, the European Commission funded a 3-year project (contract no. QLK3-CT-2000-00340) under the fifth Framework Programme to develop and test prototype products based on the oral delivery of vaccine and therapeutic agents using harmless lactic acid bacteria (LAB). The project, best known under its acronym LABDEL (for LAB delivery) also included research on LAB fermentation and technological innovations aimed at enhancing the efficiency of LAB delivery systems (1). One of the key scientific objectives was to investigate the possibility to prevent or treat a type I allergic disease using mucosal administration of LAB expressing the pollen allergen Bet v 1. The aim of this paper was to describe the background of the project with reference to a limited selection of articles and recent reviews as well as the results and major conclusions arising from this part of the project.

Are immunological mechanisms involved in colon cancer and are they possible markers for biotherapy improvement?

This paper focuses on our data on colon cancer patients. Our overall results lead us to believe that the suppressive effect of specific cytokines in colon cancer patients alters the functionality of TH1 and TH2 subsets of CD4+ T-cells, with an expansion of TH2 cells and a malfunctioning of TH1 cells. This immunological disregulation appears to increase with stage progression, suggesting a direct role in the mechanisms that allow the tumour to locate and expand within the host. It is also clear that in order to identify disease markers and generate an in vivo immune response that corrects the imbalance between TH1 and TH2 cells, we need to understand how tumour mechanisms cause this imbalance to begin with.

Impact of lactic Acid bacteria on dendritic cells from allergic patients in an experimental model of intestinal epithelium

Lactic acid bacteria (LAB) are Gram positive nonpathogenic commensal organisms present in human gastrointestinal tract. In vivo, LAB are separated from antigen-presenting cells such as dendritic cells (DC) by the intestinal epithelial barrier. In this study, the impact of one LAB strain (Lactobacillus casei ATCC393) on human monocyte-derived DC from allergic and healthy donors was assessed by using a polarized epithelium model. Confocal and flow cytometer analyses showed that immature DC efficiently captured FITC-labelled L. casei through the epithelial layer. After interaction with L. casei, DC acquired a partial maturation status (i.e., CD86 and CD54 increase) and increased their interleukin (IL)-10 and IL-12 production. Interestingly, after activation by L. casei in the presence of experimental epithelium, DC from allergic patients instructed autologous naïve CD4(+) T cells to produce more interferon-gamma than without the epithelium. Thus by modulating human DC reactivity, LAB and intestinal epithelium might modify T cell immune response and regulate the development of allergic reaction.

Heme oxygenase-1-mediated CD4+CD25high regulatory T cells suppress allergic airway inflammation

Heme oxygenase-1 (HO-1) has anti-inflammatory effects in asthma. CD4+CD25(high) regulatory T cells (Treg) are a potent immunoregulator that suppresses the immune response. We studied the effects of HO-1-mediated CD4+CD25(high) Treg on suppression of allergic airway inflammation by comparing mice treated with hemin, OVA, Sn-protoporphyrin (SnPP), and hemin plus SnPP. Airway responsiveness, airway eosinophil infiltration, the level of OVA-specific IgE, and the numbers of cells in general and eosinophils in particular in bronchial alveolar lavage fluid were lower in the hemin group than in the OVA, SnPP, and hemin plus SnPP groups. The expressions of HO-1 mRNA and protein in the lung were increased by repeated administrations of hemin and SnPP. However, the activity of HO-1 was highest in hemin mice. The percentage and suppressive function of CD4+CD25(high) Treg and the expression of Foxp3 mRNA were obviously enhanced after treatment with hemin. This increase was diminished by the administration of SnPP. The concentration of serum IL-10 was higher in the hemin group than in the other groups, whereas the level of serum TGF-beta did not significantly differ across groups. Furthermore, the ratio of IFN-gamma/IL-4 mRNA in the lung was higher in hemin-treated mice than in OVA and SnPP mice. The suppressive capacity of CD4+CD25(high) Treg was not enhanced in the IL-10-deficient mice treated with hemin. In conclusion, our experiments in the animal model demonstrated that HO-1 has anti-inflammatory effects, probably via enhancement of the secretion of IL-10 and promotion of the percentage of CD4+CD25(high) Treg.

STAT1 phosphorylation and cleavage is regulated by the histamine (H4) receptor in human atopic and non-atopic lymphocytes

Histamine can modulate the balance between T helper lymphocytes 1 and 2 (Th1 and Th2), and there is evidence that allergic reactions can be associated with excessive histamine production causing shifts toward Th2 responses. As signal transduction in Th-cells is specifically correlated to signal transducer and activator of transcription (STAT) activation and expression, the question arises whether histamine acting through histamine receptors (HR) induces modulation of the Janus kinase (JAK)-STAT pathway. Peripheral blood mononuclear cells (PBMC) from atopic and non-atopic donors were stimulated with phytohemagglutinin (PHA). Initial interleukin-4 (IL-4) levels were higher in the atopic group compared to the non-atopics and interferon-gamma (IFN-gamma) levels were lower. This was correlated to lower levels of STAT1 expression and phosphorylation. Furthermore, Western blots showed a 118-kDa STAT1 band at the start of the PHA stimulation that was apparently cleaved to STAT1alpha (91 kDa) and a 28 kDa-fragment with further stimulation. Histamine or the H4R agonist, clobenpropit, led to a significant suppression of the formation and phosphorylation of STAT1alpha in the non-atopic group after 48 h of PHA stimulation, but had no effect in the atopic group where STAT1alpha levels were already reduced. The STAT1alpha levels in the non-atopic group were enhanced by the H4R antagonist JNJ7777120. The phosphorylation of STAT1 could also be potentiated by the H4R antagonist, mimicking the precursor responses of STAT1alpha. JNJ7777120 also increased the binding of STAT1 to DNA and this effect could be reversed by histamine. As for histamine, the effects of the H4R antagonist were only seen in the non-atopic group. These results suggest that, in non-atopic individuals, histamine acting via the H4R can influence STAT1 regulation, but that this pathway is not present in atopics perhaps due to constitutive suppression of STAT1 activity.