transforming-growth-factor-beta and Aspergillosis--Allergic-Bronchopulmonary

CpG-rich oligodeoxynucleotides activate the immune system, leading to innate and acquired immune responses. The immune-stimulatory effects of CpG-rich oligodeoxynucleotides are being exploited as a therapeutic approach. Here we show that at high doses, CpG-rich oligodeoxynucleotides promote an opposite, tolerogenic response in mouse plasmacytoid dendritic cells in vivo and in a human in vitro model. Unveiling a previously undescribed role for TRIF and TRAF6 proteins in Toll-like receptor 9 (TLR9) signalling, we demonstrate that physical association of TLR9, TRIF and TRAF6 leads to activation of noncanonical NF-κB signalling and the induction of IRF3- and TGF-β-dependent immune-suppressive tryptophan catabolism. In vivo, the TLR9-TRIF circuit--but not MyD88 signalling--was required for CpG protection against allergic inflammation. Our findings may be relevant to an increased understanding of the complexity of Toll-like receptor signalling and optimal exploitation of CpG-rich oligodeoxynucleotides as immune modulators.

Topics: Adaptor Proteins, Vesicular Transport; Animals; Antigens, CD; Aspergillosis, Allergic Bronchopulmonary; Dendritic Cells; Gene Expression Regulation; Humans; Immune Tolerance; Immunomodulation; Indoleamine-Pyrrole 2,3,-Dioxygenase; Interferon Regulatory Factors; Interferon Type I; Interleukin-23; Membrane Glycoproteins; Mice; Myeloid Differentiation Factor 88; NF-kappa B; Oligodeoxyribonucleotides; Pneumonia; Signal Transduction; Skin Tests; Toll-Like Receptor 3; Toll-Like Receptor 4; Toll-Like Receptor 9; Transforming Growth Factor beta; Tumor Necrosis Factor Receptor-Associated Peptides and Proteins

Allergic bronchopulmonary aspergillosis (ABPA) is caused by a dominant Th2 immune response to antigens derived from the opportunistic mold Aspergillus, most commonly Aspergillus fumigatus. It occurs in 4%-15% of patients with cystic fibrosis (CF); however, not all patients with CF infected with A. fumigatus develop ABPA. Therefore, we compared cohorts of A. fumigatus-colonized CF patients with and without ABPA to identify factors mediating tolerance versus sensitization. We found that the costimulatory molecule OX40 ligand (OX40L) was critical in driving Th2 responses to A. fumigatus in peripheral CD4+ T cells isolated from patients with ABPA. In contrast, CD4+ T cells from the non-ABPA cohort did not mount enhanced Th2 responses in vitro and contained a higher frequency of TGF-beta-expressing regulatory T cells. Heightened Th2 reactivity in the ABPA cohort correlated with lower mean serum vitamin D levels. Further, in vitro addition of 1,25 OH-vitamin D3 substantially reduced DC expression of OX40L and increased DC expression of TGF-beta. This in vitro treatment also resulted in increased Treg TGF-beta expression and reduced Th2 responses by CD4+ T cells from patients with ABPA. These data provide rationale for a therapeutic trial of vitamin D to prevent or treat ABPA in patients with CF.

Topics: Adult; Aspergillosis, Allergic Bronchopulmonary; Aspergillus; Aspergillus fumigatus; CD4-Positive T-Lymphocytes; Cholecalciferol; Cystic Fibrosis; Female; Humans; Male; Receptors, OX40; T-Lymphocytes, Regulatory; Th2 Cells; Transforming Growth Factor beta

Aspergillus fumigatus is ubiquitous and yet causes invasive, chronic and allergic disease of the lung. Chronic cavitary pulmonary aspergillosis (CCPA) is a slowly destructive form of pulmonary aspergillosis, without immunocompromise. We hypothesized that CCPA cytokine gene polymorphisms would differ from patients with allergic bronchopulmonary aspergillosis (ABPA) and uninfected controls. We have profiled functional cytokine gene polymorphisms for interleukin (IL)-10, IL-15, transforming growth factors (TGF)-beta1, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma in patients with CCPA (n = 24) who were compared with other forms of aspergillosis (mostly ABPA) (n = 15) and with ethnically matched controls (n = 65-330). Results are described with reference to the high-producing genotype in each case. Susceptibility to aspergillosis (all patients compared with normal controls) was associated with higher frequency of the IL-15 +13689*A allele (OR = 2.37, P = 0.0028) and A/A genotype (chi(2) = 10.31, P < 0.001), with a lower frequency of the TNF-alpha-308*A/A genotype (chi(2) = 11.05, P < 0.01). Within the aspergillosis patients, CCPA is associated with lower frequency of the IL-10 -1082*G allele (OR = 0.38, P = 0.0006) and G/G genotype (chi(2) = 22.45, P < 0.001) and with a lower frequency of the TGF-beta1 +869 *T allele (OR +0.42, P < 0.0029) and T/T genotype (chi(2) = 17.82, P < 0.001) compared with non-CCPA patients and normal controls. Patients infected with Aspergillus appear to be higher producers of IL-15, a Th2-promoting cytokine, and lower producers of TNF-alpha, a cytokine central in protective responses. CCPA occurs in patients who are genetically lower producers of both IL-10 and TGF-beta1. As these cytokines are regulatory and anti-inflammatory, CCPA may be a consequence of poor inflammatory response control in the lung.

Topics: Adult; Aspergillosis; Aspergillosis, Allergic Bronchopulmonary; Aspergillus fumigatus; Case-Control Studies; Cytokines; England; Genetic Predisposition to Disease; Genotype; Humans; Interferon-gamma; Interleukin-10; Interleukin-15; Lung Diseases, Fungal; Middle Aged; Polymerase Chain Reaction; Sinusitis; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tumor Necrosis Factor-alpha

Signal transducer and activator of transcription 6 (Stat6) is critical for Th2-mediated responses during allergic airway disease. To investigate the role of Stat6 in fungus-induced airway hyperresponsiveness and remodeling, Stat6-deficient (Stat6-/-) and Stat6-wildtype (Stat6+/+) mice were sensitized to Aspergillus fumigatus and airway disease was subsequently assessed in both groups at days 21, 30, 38, and 44 after an intratracheal challenge with live A. fumigatus conidia. At all times after conidia, histological analysis revealed an absence of goblet cell hyperplasia and markedly diminished peribronchial inflammation in Stat6-/- mice in contrast to Stat6+/+ mice. Airway hyperresponsiveness and peribronchial fibrosis in Stat6-/- mice were significantly reduced at day 21 after conidia compared with Stat6+/+ mice, but both groups exhibited significant, similar increases in these parameters at all subsequent times after conidia. In separate experiments, IL-13-responsive cells in Stat6-/- mice were targeted via the daily intranasal administration of 200 ng of IL-13-PE38QQR (IL13-PE), comprised of human IL-13 and a derivative of Pseudomonas exotoxin, from days 38 to 44 after the conidia challenge. IL13-PE treatment abolished airway hyperresponsiveness, but not peribronchial fibrosis in Stat6-/- mice. Taken together, these data demonstrate that the chronic development of airway hyperresponsiveness during fungal asthma is IL-13-dependent but Stat6-independent.

Topics: Animals; Aspergillosis, Allergic Bronchopulmonary; Aspergillus fumigatus; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Chemokine CCL11; Chemokine CCL2; Chemokine CCL5; Chemokines, CC; Chronic Disease; Collagen; Humans; Immunoglobulin E; Interleukin-13; Interleukin-4; Leukocytes; Lung; Mice; Mice, Inbred BALB C; Mice, Transgenic; Pulmonary Fibrosis; STAT6 Transcription Factor; T-Lymphocytes; Trans-Activators; Transforming Growth Factor beta