Regulation of cytokine production in T-cell responses to inhalant allergen:GATA-3 expression distinguishes between Th1- and Th2-polarized immunity

Allergens induce upregulated IL-18 and IL-18Rα expression in blood Th2 and Th17 cells of patients with allergic asthma

Allergic asthma (AA) is closely associated with the polarization of T helper (Th)2 and Th17 cells. Interleukin (IL)-18 acts as an inducer of Th2 and Th17 cell responses. However, expressions of IL-18 and IL-18 receptor alpha (IL-18Rα) in blood Th2 and Th17 cells of patients with AA remain unclear. We therefore investigated their expressions in Th2 and Th17 cells using flow cytometric analysis, quantitative real-time PCR (qPCR), and murine AA model. We observed increased proportions of Th2, Th17, IL-18+, IL-18+ Th2, and IL-18+ Th17 cells in blood CD4+ T cells of patients with AA. Additionally, house dust mite seemed to upregulate further IL-18 expression in Th2 and Th17, and upregulate IL-18Rα expression in CD4+ T, Th2, and Th17 cells of AA patients. It was also found that the plasma levels of IL-4, IL-17A, and IL-18 in AA patients were elevated, and they were correlated between each other. In ovalbumin (OVA)-induced asthma mouse (AM), we observed that the percentages of blood CD4+ T, Th2, and Th17 cells were increased. Moreover, OVA-induced AM expressed higher level of IL-18Rα in blood Th2 cells, which was downregulated by IL-18. Increased IL-18Rα expression was also observed in blood Th2 cells of OVA-induced FcεRIα-/- mice. Collectively, our findings suggest the involvement of Th2 cells in AA by expressing excessive IL-18 and IL-18Rα in response to allergen, and that IL-18 and IL-18Rα expressing Th2 cells are likely to be the potential targets for AA therapy.

Association of neuropeptides with Th1/Th2 balance and allergic sensitization in children

BACKGROUND

Among neurogenic factors, the neuropeptides have an important regulatory influence on immune system activity and may lead to allergic sensitization.

OBJECTIVE

The aim of our study was to investigate the relationship of the neuropeptides vasoactive intestinal peptide (VIP), somatostatin (SOM) and substance P (SP) on modulation of Th1/Th2 balance and allergic sensitization in children.

METHODS

Within the LISAplus (Life style-Immune system-Allergy) study, blood samples of 321 six-year-old children were analysed for concentration of neuropeptides, Th1 and Th2 cytokines, transcription factors for T cell regulation and suppressors of cytokine signalling. In addition, samples were screened for specific IgE against inhalant and food allergens.

RESULTS

Children with high SOM values showed a Th2 polarization and a reduced expression of FOXP3, the marker for regulatory T cells. High (VIP) levels correlated inversely with the expression of T cell transcription factors (Tbet and SOCS3). In contrast, elevated levels of SP were associated with reduced GATA3 and SOCS3 expression and with increased IFN-gamma concentrations. Allergic sensitization was more prevalent in children with higher SOM and VIP concentrations but not associated with SP levels.

CONCLUSION

Our data reveal an association between neuropeptides and modulatory effects on immune cells in vivo, especially on Th1/Th2 balance with a correlation to allergic sensitization in children. We suggest that elevated SOM and VIP concentrations and the inducing factors should be considered as allergy risk factors.

Use of mouse models of allergic rhinitis to study the upper and lower airway link

PURPOSE OF REVIEW

Allergic rhinitis and asthma are examples of a continuum of airway diseases with diverse clinical manifestations. This review examines the most recent work in mouse models studying upper and lower airway links and interactions.

RECENT FINDINGS

The concept of united airways has been supported by investigative and epidemiological studies. Studies using mouse models of asthma and models of allergic rhinitis have demonstrated that analogous pathways lead to inflammation and airway hyperresponsiveness. Th2-type T cells and IL-13 play important immunopathologic roles. Recent studies have examined upper airway mucosal immune responses and development of both allergic and tolerant phenotypes. In a model of allergic airways disease, there is evidence of lower airway inflammation and airways hyperresponsiveness following application of allergen only to the nares, suggesting local stimulation can activate distal allergic responses. Immunomodulatory properties of the airway mucosa have also been explored. Allergen-specific tolerance can be induced by appropriate stimulation of airway mucosa and is associated with activation of IL-10-producing T cells. This effect is mediated by antigen presenting cells, especially dendritic cells.

SUMMARY

Immune stimulation of the airway mucosa, both in the upper and lower airways, results in active T-cell-mediated immune responses leading toward tolerance or asthma and allergic rhinitis. Regulation of these T-cell responses is currently under investigation. It is clear from these studies that antigenic stimulation of any part of the respiratory mucosa can have ripple effects along the entire airway and supports the concept of united airways.

Nuclear factor kappa B activation in human cord blood mononuclear cells

The immunologic signals participating in immune responses early in life have not been completely elucidated. Regarding the characterization of neonatal cells, little is known concerning the activity of transcription factor nuclear factor kappa B (NF-kappaB), which regulates inflammatory genes and cytokine production. The aim of this study was to characterize NF-kappaB activation in cord blood mononuclear cells (CBMC). We analyzed the potential association of NF-kappaB activity with lymphocyte proliferation and influences on cytokine secretion in the early immune system. To determine the contribution of a disease whereby inheritance may impact neonatal immunity, we assessed the influence of maternal allergic disease on NF-kappaB regulation and cytokine secretion. CBMC from healthy newborns were isolated and stimulated with mitogen (n = 28). Nuclear extracts were analyzed by electrophoretic mobility shift assay, cytokine secretion by ELISA. FISH analysis excluded relevant maternal contamination of CBMC. All samples showed a positive lymphoproliferative response, and NF-kappaB activity was both increased and decreased after mitogen stimulation. Increased NF-kappaB activation was significantly associated with decreased TNF-alpha secretion (median 6.1 versus 50.3 pg/mL) in unstimulated CBMC. Mitogen stimulation resulted in increased NF-kappaB activity with a trend to increased IL-13 production. Maternal allergic disease was associated with higher TNF-alpha (median 982 versus 173 pg/mL) and IL-13 secretion (median 1328 versus 1120 pg/mL) after mitogen stimulation. Together, NF-kappaB activity is differentially activated in cord blood and associated with a distinct cytokine pattern. Whether differential NF-kappaB activity in cord blood is related to the subsequent development of immune diseases requires further investigation.

Endogenous GATA Factors Bind the Core Sequence of the tetO and Influence Gene Regulation with the Tetracycline System

The tetracycline-regulated eukaryotic gene expression systems have been applied in numerous areas of bioscience. The systems utilize a tetracycline-responsive promoter (P(tet)) and synthetic transactivators (tTA or rtTA) that bind to the promoter in the presence or absence of doxycycline, regulating gene expression. Both the basal activity of the P(tet) and the magnitude of regulation by the system vary between cell types. In this investigation we have mapped the positions of endogenous transcription factor binding sites within the P(tet) and through deletion studies determined the portion of the promoter that contributes to basal activity. The tetracycline operator (tetO) repeats appear to be the source of basal activity and they were shown to harbor motifs for GATA transcription factors. The GATA motif is located within the central core of the tetO and so has the potential to compete with tTA and rtTA binding. The molecular interactions of endogenous and overexpressed GATA factors with the GATA motif in the tetO were demonstrated and effects on function of the tetracycline-regulated gene expression system investigated. GATA factors are widespread in embryonic tissues, are expressed within several adult cell types, and display altered expression in disease states. We suggest that endogenous GATA factor expression may influence the degree of gene regulation by the tetracycline system between different cell types. The findings of this study may have implications for the application of the tetracycline system in gene therapy.

The role of genetic and environmental factors in the development of T-cell mediated allergic disease in early life

Cognate immunity to inhalant allergens is virtually universal within the adult population, but in the majority of cases this does not progress to the development of persistent asthma. Accumulating evidence suggests that progression from moderate to severe allergic disease is associated with a series of host and environmental factors operative during early childhood which interact to increase risk for both allergic sensitisation and severe respiratory infection, within the same subjects.

The role of airway dendritic cell populations in regulation of T-cell responses to inhaled antigens: atopic asthma as a paradigm

Chronic atopic asthma in adulthood represents the end stage of a disease process that is initiated during the perinatal period, when the naive immune system is first confronted with potentially allergenic airborne antigens. The initial phase involves compartmentalization of immunological memory into either the T-helper (Th)-1 or Th2 cytokine phenotypes, in atopic and nonatopics, respectively, and in a subset of atopics, this results in chronic Th2 cytokine-driven inflammation in the airways. Dendritic cells appear to play a key role in directing the memory generation process, and in subsequently controlling the intensity and duration of the ensuing Th-cell responses responsible for this inflammation.