Mouse Natural Killer (NK) Cells Express the Nerve Growth Factor Receptor TrkA, which Is Dynamically Regulated

Background: Nerve growth factor (NGF) is a neurotrophin crucial for the development and survival of neurons. It also acts on cells of the immune system which express the NGF receptors TrkA and p75 NTR and can be produced by them. However, mouse NK cells have not yet been studied in this context. Methodology/Principal Findings: We used cell culture, flow cytometry, confocal microscopy and ELISA assays to investigate the expression of NGF receptors by NK cells and their secretion of NGF. We show that resting NK cells express TrkA and that the expression is different on NK cell subpopulations defined by the relative presence of CD27 and CD11b. Expression of TrkA is dramatically increased in IL-2-activated NK cells. The p75 NTR is expressed only on a very low percentage of NK cells. Functionally, NGF moderately inhibits NK cell degranulation, but does not influence proliferation or cytokine production. NK cells do not produce NGF. Conclusions/Significance: We demonstrate for the first time that mouse NK cells express the NGF receptor TrkA and tha

Phenotypic Studies of Natural Killer Cell Subsets in Human Transporter Associated with Antigen Processing Deficiency

Peripheral blood natural killer (NK) cells from patients with transporter associated with antigen processing (TAP) deficiency are hyporesponsive. The mechanism of this defect is unknown, but the phenotype of TAP-deficient NK cells is almost normal. However, we noticed a high percentage of CD56bright cells among total NK cells from two patients. We further investigated TAP-deficient NK cells in these patients and compared them to NK cells from two other TAP-deficient patients with no clinical symptoms and to individuals with chronic inflammatory diseases other than TAP deficiency (chronic lung diseases or vasculitis). Peripheral blood mononuclear cells isolated from venous blood were stained with fluorochrome-conjugated antibodies and the phenotype of NK cells was analyzed by flow cytometry. In addition, 51Chromium release assays were performed to assess the cytotoxic activity of NK cells. In the symptomatic patients, CD56bright NK cells represented 28% and 45%, respectively, of all NK cells (higher than in healthy donors). The patients also displayed a higher percentage of CD56dimCD16− NK cells than controls. Interestingly, this unusual NK cell subtype distribution was not found in the two asymptomatic TAP-deficient cases, but was instead present in several of the other patients. Over-expression of the inhibitory receptor CD94/NKG2A by TAP-deficient NK cells was confirmed and extended to the inhibitory receptor ILT2 (CD85j). These inhibitory receptors were not involved in regulating the cytotoxicity of TAP-deficient NK cells. We conclude that expansion of the CD56bright NK cell subtype in peripheral blood is not a hallmark of TAP deficiency, but can be found in other diseases as well. This might reflect a reaction of the immune system to pathologic conditions. It could be interesting to investigate the relative distribution of NK cell subsets in various respiratory and autoimmune diseases

Acariens et allergies (contribution à l'étude des allergènes de dermatophagoides pteronyssinus et d'argas reflexus)

STRASBOURG ILLKIRCH-Pharmacie (672182101) / SudocSudocFranceF

Long-Term Pollen Monitoring in the Benelux: Evaluation of Allergenic Pollen Levels and Temporal Variations of Pollen Seasons

Airborne pollen is a major cause of allergic rhinitis, affecting between 10 and 30% of the population in Belgium, the Netherlands, and Luxembourg (Benelux). Allergenic pollen is produced by wind pollinating plants and released in relatively low to massive amounts. Current climate changes, in combination with increasing urbanization, are likely to affect the presence of airborne allergenic pollen with respect to exposure intensity, timing as well as duration. Detailed analysis of long-term temporal trends at supranational scale may provide more comprehensive insight into these phenomena. To this end, the Spearman correlation was used to statistically compare the temporal trends in airborne pollen concentration monitored at the aerobiological stations which gathered the longest time-series (30–44 years) in the Benelux with a focus on the allergenic pollen taxa: Alnus, Corylus, Betula, Fraxinus, Quercus, Platanus, Poaceae, and Artemisia. Most arboreal species showed an overall trend toward an increase in the annual pollen integral and peak values and an overall trend toward an earlier start and end of the pollen season, which for Betula resulted in a significant decrease in season length. For the herbaceous species (Poaceae and Artemisia), the annual pollen integral and peak values showed a decreasing trend. The season timing of Poaceae showed a trend toward earlier starts and longer seasons in all locations. In all, these results show that temporal variations in pollen levels almost always follow a common trend in the Benelux, suggesting a similar force of climate change-driven factors, especially for Betula where a clear positive correlation was found between changes in temperature and pollen release over time. However, some trends were more local-specific indicating the influence of other environmental factors, e.g., the increasing urbanization in the surroundings of these monitoring locations. The dynamics in the observed trends can impact allergic patients by increasing the severity of symptoms, upsetting the habit of timing of the season, complicating diagnosis due to overlapping pollen seasons and the emergence of new symptoms due allergens that were weak at&nbsp;first.</p

Proteomic analysis of horse hair extracts provides no evidence for the existence of a hypoallergenic Curly Horse breed

Abstract Background The American Bashkir Curly Horse is frequently advertised to horse‐allergic riders and claimed to be a so‐called hypoallergenic breed that elicits fewer symptoms. Previous studies quantifying selected allergens in different breeds did not find a reduced allergen content in Curly Horses. Here, we provide a comprehensive proteomic analysis of horse hair extracts and a molecular analysis of the major allergen Equ c 1 with the aim of identifying differences in the Curly Horse breed that might explain their presumed reduced allergenic potential. Methods Horse hair extracts were prepared from Curly and American Quarter Horse breeds, separated by gender and castration status, extracts from other breeds served as controls. Extracts and native Equ c 1 (nEqu c 1) were analyzed by mass spectrometry. IgE‐binding capacities of nEqu c 1 and its recombinant variants were tested by ELISA using sera of patients sensitized to horses. Structures and ligand binding abilities were analyzed by computational modeling and fluorescence quenching assays. Results All known respiratory horse allergens are present in hair extracts of Curly and Quarter Horses and share identical allergen‐specific peptides. Lipocalin allergens are the most abundant proteins in horse hair extracts and contain several post‐translational modifications. We identified two new variants of Equ c 1 that have similar IgE‐binding capacities but show structural differences in their binding cavities and altered ligand binding behavior. There are no differences in IgE‐binding of Equ c 1 derived from Curly Horses compared to other horse breeds. Conclusion Our data do not support the claim that Curly Horses are less allergenic than other breeds