Project description:Foxp3+ regulatory T cells (Treg) play a central role for tolerance against self and innocuous environmental antigens. However, the role of antigen-specificity for Treg-mediated tolerance is only incompletely understood. Here we show by direct ex vivo characterization of human CD4+ T cells, that the response against innocuous airborne antigens, such as plant pollen or fungal spores, is dominated by memory-like antigen-specific Treg. Surprisingly, breakdown of tolerance in atopic donors was not accompanied by a quantitatively or qualitatively altered Treg response, but instead correlated with a striking dichotomy of Treg versus Th2 target specificity. Allergenic proteins, are selectively targeted by Th2 cells, but not Treg. Thus human Treg specific for airborne antigens maintain tolerance at mucosal sites and the failure to generate specific Treg against a subgroup of antigens provides a window of opportunity for allergy development. PBMCs from sex and age matched birch pollen allergic patients and healthy controls, were stimulated (7h) with airborne fungal (A. fumigatus) or birch pollen antigen (birch) and sorted into antigen specific conventional and regulatory T cells according to their expression of CD154+ and CD137+ on CD4+ T cells, respectively. Number of samples per group in parentheses: Healthy controls stimulated with A. fumigatus (n=5), allergic patients stimulated with A. fumigatus (n=6), healthy controls stimulated with birch (n=6), allergic patients stimulated with birch (n=4).
Project description:Analysis of germinal center B cells derived from WT and SAP-deficient mice revealed that SAP-deficient mice have reduced Myc signature
Project description:Human BEAS-2B were exposed to whole birch pollen using a Pollen Sedimentation Chamber. The chamber was designed to be able to dose cells to dry whole pollen. The goal was to understand the reaction of human epithelial cells to a human real life pollen exposure.
Project description:We have used transgenic ethylene-insensitive birches (Betula pendula), which express the Arabidopsis ethylene receptor gene ETR1 carrying the dominant mutation etr1-1, to investigate the role of ethylene in short day (SD) -induced responses in the shoot apical meristem in birch. Wild-type birch (clone V5834) and two ethylene-insensitive lines in this background (BPetr1-1-35 and BPetr1-1-86; see Plant Physiol 132: 185-195) were exposed to SD. After 12, 16 and 20 days under SD, apices of branches of three trees were pooled before RNA extraction from each sample. To study the ethylene-dependent SD-transcriptome in birch apices, the RNA extracts of lines BPetr1-1-35 and BPetr1-1-86 were separately compared with the reference, wild-type V5834, at the three time points (12SD, 16SD, 20SD) resulting in altogether six microarray hybridizations.
Project description:We performed small RNA-seq (sRNA-seq) study of Arabidopsis phloem sap under iron-sufficient (+Fe; control) and iron deficient (-Fe) conditions to investigate and identify sRNAs whose expression is regulated by iron deficiency in the phloem sap.
Project description:Sap samples from sugar maple trees across the Canadian province of Ontario were collected in 2019. These samples were minimally prepared and analyzed in both positive ESI and negative ESI by C18 and HILIC chromatography. This was done to uncover the chemical changes that occurred in the sap over the season. This will serve as the base for future analysis of maple syrup where compounds that may be responsible for specific organoleptic properties can be linked back to precursors found here in the sap.
