Increased estrogen to androgen ratio enhances immunoglobulin levels and impairs B cell function in male mice

Sex steroids, such as estrogens and androgens, are important regulators of the humoral immune response. Studies in female mice have demonstrated that alteration of circulating estrogen concentration regulates antibody-mediated immunity. As males have normally little endogenous estrogen, we hypothesized that in males high estrogens and low androgens affect the immune system and enhance the allergic inflammatory response. Here, we studied transgenic male mice expressing human aromatase (AROM+). These animals have a high circulating estrogen to androgen ratio (E/A), causing female traits such as gynecomastia. We found that AROM+ male mice had significantly higher plasma immunoglobulin levels, particularly IgE. Flow cytometry analyses of splenocytes revealed changes in mature/immature B cell ratio together with a transcriptional upregulation of the Igh locus. Furthermore, higher proliferation rate and increased IgE synthesis after IgE class-switching was found. Subsequently, we utilized an ovalbumin airway challenge model to test the allergic response in AROM+ male mice. In line with above observations, an increase in IgE levels was measured, albeit no impact on immune cell infiltration into the lungs was detected. Together, our findings suggest that high circulating E/A in males significantly alters B cell function without any significant enhancement in allergic inflammation.</p

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Role of allergen-specific CD8+ T cells in the murine asthma model.

Previous studies have indicated a divergent role for specific CD8+ T cells in allergic airway disease. To address this controversy, opposing priming conditions for CD8+ T cells using high- or low-dose allergen concentrations were applied. The recruitment of functionally active allergen-specific CD8+ T cells to the airways, which is dependent on the allergen sensitization dose, appears to be a critical predictor for the severity of the allergic phenotype in mice

Beneficial effects of cannabinoids (CB) in a murine model of allergen-induced airway inflammation: Role of CB(1)/CB(2) receptors.

The endocannabinoid system (ECS) consists of two cannabinoid (CB) receptors, namely CB(1) and CB(2) receptor, and their endogenous (endocannabinoids) and exogenous (cannabinoids, e.g. delta-9-tetrahydrocannabinol (THC)) ligands which bind to these receptors. Based on studies suggesting a role of THC and the ECS in inflammation, the objective of this study was to examine their involvement in type I hypersensitivity using a murine model of allergic airway inflammation. THC treatment of C57BL/6 wildtype mice dramatically reduced airway inflammation as determined by significantly reduced total cell counts in bronchoalveolar lavage (BAL). These effects were greatest when mice were treated during both, the sensitization and the challenge phase. Furthermore, systemic immune responses were significantly suppressed in mice which received THC during sensitization phase. To investigate a role of CB(1/2) receptors in this setting, we used pharmacological blockade of CB(1) and/or CB(2) receptors by the selective antagonists and moreover CB(1)/CB(2) receptor double-knockout mice (CB(1)(-/-)/CB(2)(-/-)) and found neither significant changes in the cell patterns in BAL nor in immunoglobulin levels as compared to wildtype mice. Our results indicate that the activation of the ECS by applying the agonist THC is involved in the development of type I allergies. However, CB(1)/CB(2) receptor-independent signalling seems likely in the observed results

TNF receptor I on human keratinocytes is a binding partner for staphylococcal protein A resulting in the activation of NF kappa B, AP-1, and downstream gene transcription.

Primary human keratinocytes and immortalized HaCaT cells were analysed for their capacity to bind purified staphylococcal protein A (SpA). Co-incubation with FITC-labelled SpA led to a dose-depending attachment. Pull-down experiments with cellular extracts revealed the TNF&alpha; receptor I (TNF RI) as binding partner on keratinocytes. Thus, we next looked for expression of this receptor in human epidermis and cultured keratinocytes. TNF RI is strongly expressed on all keratinocytes analysed, both at the mRNA and protein level and activation by SpA at optimal doses of 50-100 &mu;g/ml resulted in the phosphorylation of the TNF RI downstream kinases MEK1/2, JNK1/2, and p38 subsequently leading to translocation of the p65 NF kappa B subunit and AP-1 into the nucleus. This translocation was then followed by increased expression of IL-8 and COX-2, two known NF kappa B-induced pro-inflammatory genes. To further test the relevance of our findings, we analysed in vitro production of over 100 strains isolated from atopic eczema showing that more than 85% of the tested strains produced extracellular SpA in substantial amounts. Thus, besides superantigens, haemolysins, and other cell wall components, Staphylococcus aureus exerts pro-inflammatory stimuli on human keratinocytes through the production of SpA signalling through TNF RI

Endothelial amine oxidase AOC3 transiently controbutes to adaptive immune responses in the airways.

AOC3 (Amine oxidase, copper containing 3, also known as vascular adhesion protein-1 (VAP-1)) is an endothelial adhesion molecule that contributes to the extravasation of neutrophils, macrophages and lymphocytes to sites of inflammation. However, the role of AOC3/VAP-1 in allergic responses remains unknown. Here we studied eosinophil and CD4+ T-cell recruitment to the airways using AOC3/VAP-1-deficient mice. In an OVA-triggered asthma model, AOC3/VAP-1 slightly contributed to the accumulation of leukocytes in lungs in an age-dependent manner. We then established a new model to kinetically measure recruitment of OVA-specific CD4+ T cells to different airway immune compartments during the priming and effector phases of an adaptive immune response. The results showed that in the absence of AOC3/VAP-1, recruitment of antigen-specific CD4+ T cells to draining bronchial lymph nodes is reduced by 89% on day 3 after tracheal allergen exposure, but this difference was not observed on day 6. The dispersal of effector cells to lung and tracheal mucosa is AOC3/VAP-1-independent. Thus, in allergic airway reactions, AOC3/VAP-1 transiently contributes to the antigen-specific, CD4+ T-cell traffic to secondary lymphatic tissues, but not to airway mucosa or lung parenchyma. Our results suggest a largely redundant function for AOC3/VAP-1 in allergic inflammatory responses of the airways

Specific CD8 T cells in IgE-mediated allergy correlate with allergen dose and allergic phenotype.

RATIONALE: Studies in humans and rodents have indicated a causative role for CD8(+) T cells in IgE-mediated allergic inflammation, but their function is still controversial. OBJECTIVES: To analyze the role of allergen-specific CD8(+) T cells during the development of allergic airway inflammation in two parallel but diverging outcome models. METHODS: We used H2-Kb SIINFEKL (OVA(257-264)) multimers to analyze induction, natural distribution, and phenotype of allergen-specific CD8(+) T cells in a murine C57BL/6 model of ovalbumin (OVA)-induced allergic airway inflammation using low-dose or high-dose OVA sensitization. MEASUREMENTS AND MAIN RESULTS: The low-dose protocol was characterized by a significant induction of total and OVA-specific IgE, eosinophilic airway inflammation, IL-4 levels in bronchoalveolar lavage fluid. And significant alterations in lung function. The high dose protocol was characterized by a significant reduction of the allergic phenotype. Using OVA(257-264) H2-Kb multimers, we observed lung and airway infiltrating OVA-specific CD8(+) T cells showing an effector/effector-memory phenotype. The high-dose protocol caused significantly higher infiltration of allergen-specific CD8(+) cells to the airways and enhanced their cytotoxicity. Adoptive transfer with CD8(+) T cells from transgenic OT-I mice to TAP1(-/-) or wild-type mice showed their migration to the lungs and TAP1-dependent proliferation after OVA-aerosol exposure. TAP1(-/-) mice defective in CD8(+) T cells showed exacerbated symptoms in the low-dose sensitization model. CONCLUSIONS: Allergen-specific CD8(+) T cells seem to protect from allergic inflammation in the lungs. Their number, which is dependent on the sensitization dose, appears to be a critical predictor for the severity of the allergic phenotype