95 research outputs found

    Transcriptional Analysis of the Human IgE-Expressing Plasma Cell Differentiation Pathway

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    IgE is secreted by plasma cells (PCs) and is central to allergic disease. Using an ex vivo tonsil B cell culture system, which mimics the Th2 responses in vivo, we have recently characterized the development pathway of human IgE-expressing PCs. In this system, as in mice, we reported the predisposition of IgE-expressing B cells to differentiate into PCs. To gain a comprehensive understanding of the molecular events involved in the differentiation of human IgE+ B cells into PCs we have used the Illumina HumanHT-12 v4 Expression BeadChip array to analyse the gene expression profile of ex vivo generated human IgE+ B cells at various stages of their differentiation into PCs. We also compared the transcription profiles of IgE+ and IgG1+ cells to discover isotype-specific patterns. Comparisons of IgE+ and IgG1+ cell transcriptional profiles revealed molecular signatures specific for IgE+ cells, which diverge from their IgG1+ cell counterparts upon differentiation into PCs. At the germinal center (GC) stage of development, unlike in some mouse studies of IgE biology, we observed similar rates of apoptosis and no significant differences in the expression of apoptosis-associated genes between the IgE+ and IgG1+ B cells. We identified a gene interaction network associated with early growth response 1 (EGR1) that, together with the up-regulated IRF4, may account for the predisposition of IgE+ B cells to differentiate into PCs. However, despite their swifter rates of PC differentiation, the transcription profile of IgE+ PCs is more closely related to IgE+ and IgG1+ plasmablasts (PBs) than to IgG1+ PCs, suggesting that the terminal differentiation of IgE+ cells is impeded. We also show that IgE+ PCs have increased levels of apoptosis suggesting that the IgE+ PCs generated in our in vitro tonsil B cell cultures, as in mice, are short-lived. We identified gene regulatory networks as well as cell cycle and apoptosis signatures that may explain the diverging PC differentiation programme of these cells. Overall, our study provides a detailed analysis of the transcriptional pathways underlying the differentiation of human IgE-expressing B cells and points to molecular signatures that regulate IgE+ PC differentiation and function

    Ontogeny of Human IgE-expressing B Cells and Plasma Cells

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    BACKGROUND: IgE‐expressing (IgE(+)) plasma cells (PCs) provide a continuous source of allergen‐specific IgE that is central to allergic responses. The extreme sparsity of IgE(+) cells in vivo has confined their study almost entirely to mouse models. OBJECTIVE: To characterize the development pathway of human IgE(+) PCs and to determine the ontogeny of human IgE(+) PCs. METHODS: To generate human IgE(+) cells, we cultured tonsil B cells with IL‐4 and anti‐CD40. Using FACS and RT‐PCR, we examined the phenotype of generated IgE(+) cells, the capacity of tonsil B‐cell subsets to generate IgE(+) PCs and the class switching pathways involved. RESULTS: We have identified three phenotypic stages of IgE(+) PC development pathway, namely (i) IgE(+)germinal centre (GC)‐like B cells, (ii) IgE(+) PC‐like ‘plasmablasts’ and (iii) IgE(+) PCs. The same phenotypic stages were also observed for IgG1(+) cells. Total tonsil B cells give rise to IgE(+) PCs by direct and sequential switching, whereas the isolated GC B‐cell fraction, the main source of IgE(+) PCs, generates IgE(+) PCs by sequential switching. PC differentiation of IgE(+) cells is accompanied by the down‐regulation of surface expression of the short form of membrane IgE (mIgE(S)), which is homologous to mouse mIgE, and the up‐regulation of the long form of mIgE (mIgE(L)), which is associated with an enhanced B‐cell survival and expressed in humans, but not in mice. CONCLUSION: Generation of IgE(+) PCs from tonsil GC B cells occurs mainly via sequential switching from IgG. The mIgE(L)/mIgE(S) ratio may be implicated in survival of IgE(+) B cells during PC differentiation and allergic disease

    The ecological and life history correlates of boldness in free-ranging lizards

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    In many animal populations, individuals exhibit repeatable behavioral traits across a range of contexts, and similarly, individuals differ in ecological traits such as habitat use, home range sizes, growth rates, and mating success. However, links between an individual\u27s positions on behavioral vs. ecological axes of variation remain relatively unstudied in the wild. In the course of fieldwork on a remote floodplain in tropical Australia, we quantified boldness and ecological traits in 86 free-ranging (radio-tracked) monitor lizards (Varanus panoptes). These large (up to 7 kg) lizards exhibited a spectrum of boldness, as reflected in correlated scores of responses to approach, handling, and novel prey. Bolder lizards had larger core home ranges and higher mating success and spent more time in areas of high predator abundance, and their seasonal regimes of predation-induced mortality differed from those of shyer lizards. Thus, behavioral differences among lizards underpin much of the variation in ecological traits and individual fitness within this population. Analyses of ecology and microevolution in natural populations cannot afford to ignore the complex covariation between behavior, ecology, and evolution in the wild

    Human marginal zone B cell development from early T2 progenitors.

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    B cells emerge from the bone marrow as transitional (TS) B cells that differentiate through T1, T2, and T3 stages to become naive B cells. We have identified a bifurcation of human B cell maturation from the T1 stage forming IgMhi and IgMlo developmental trajectories. IgMhi T2 cells have higher expression of α4ÎČ7 integrin and lower expression of IL-4 receptor (IL4R) compared with the IgMlo branch and are selectively recruited into gut-associated lymphoid tissue. IgMhi T2 cells also share transcriptomic features with marginal zone B cells (MZBs). Lineage progression from T1 cells to MZBs via an IgMhi trajectory is identified by pseudotime analysis of scRNA-sequencing data. Reduced frequency of IgMhi gut-homing T2 cells is observed in severe SLE and is associated with reduction of MZBs and their putative IgMhi precursors. The collapse of the gut-associated MZB maturational axis in severe SLE affirms its existence in health

    Cluster and MMS simultaneous observations of magnetosheath high speed jets and their impact on the magnetopause

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    When the supersonic solar wind encounters the Earth's magnetosphere a shock, called bow shock, is formed and the plasma is decelerated and thermalized in the magnetosheath downstream from the shock. Sometimes, however, due to discontinuities in the solar wind, bow shock ripples or ionized dust clouds carried by the solar wind, high speed jets (HSJs) are observed in the magnetosheath. These HSJs have typically a Vx component larger than 200 km s−1 and their dynamic pressure can be a few times the solar wind dynamic pressure. They are typically observed downstream from the quasi-parallel bow shock and have a typical size around one Earth radius (RE) in XGSE. We use a conjunction of Cluster and MMS, crossing simultaneously the magnetopause, to study the characteristics of these HSJs and their impact on the magnetopause. Over 1 h 15 min interval in the magnetosheath, Cluster observed 21 HSJs. During the same period, MMS observed 12 HSJs and entered the magnetosphere several times. A jet was observed simultaneously by both MMS and Cluster and it is very likely that they were two distinct HSJs. This shows that HSJs are not localized into small regions but could span a region larger than 10 RE, especially when the quasi-parallel shock is covering the entire dayside magnetosphere under radial IMF. During this period, two and six magnetopause crossings were observed, respectively, on Cluster and MMS with a significant angle between the observation and the expected normal deduced from models. The angles observed range between from 11° up to 114°. One inbound magnetopause crossing observed by Cluster (magnetopause moving out at 142 km s−1) was observed simultaneous to an outbound magnetopause crossing observed by MMS (magnetopause moving in at −83 km s−1), showing that the magnetopause can have multiple local indentation places, most likely independent from each other. Under the continuous impacts of HSJs, the magnetopause is deformed significantly and can even move in opposite directions at different places. It can therefore not be considered as a smooth surface anymore but more as surface full of local indents. Four dust impacts were observed on MMS, although not at the time when HSJs are observed, showing that dust clouds would have been present during the observations. No dust cloud in the form of Interplanetary Field Enhancements was however observed in the solar wind which may exclude large clouds of dust as a cause of HSJs. Radial IMF and AlfvĂ©n Mach number above 10 would fulfill the criteria for the creation of bow shock ripples and the subsequent crossing of HSJs in the magnetosheath.publishedVersio

    The prevalence of common mental disorders and PTSD in the UK military: using data from a clinical interview-based study

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    <p>Abstract</p> <p>Background</p> <p>The mental health of the Armed Forces is an important issue of both academic and public interest. The aims of this study are to: a) assess the prevalence and risk factors for common mental disorders and post traumatic stress disorder (PTSD) symptoms, during the main fighting period of the Iraq War (TELIC 1) and later deployments to Iraq or elsewhere and enlistment status (regular or reserve), and b) compare the prevalence of depression, PTSD symptoms and suicidal ideation in regular and reserve UK Army personnel who deployed to Iraq with their US counterparts.</p> <p>Methods</p> <p>Participants were drawn from a large UK military health study using a standard two phase survey technique stratified by deployment status and engagement type. Participants undertook a structured telephone interview including the Patient Health Questionnaire (PHQ) and a short measure of PTSD (Primary Care PTSD, PC-PTSD). The response rate was 76% (821 participants).</p> <p>Results</p> <p>The weighted prevalence of common mental disorders and PTSD symptoms was 27.2% and 4.8%, respectively. The most common diagnoses were alcohol abuse (18.0%) and neurotic disorders (13.5%). There was no health effect of deploying for regular personnel, but an increased risk of PTSD for reservists who deployed to Iraq and other recent deployments compared to reservists who did not deploy. The prevalence of depression, PTSD symptoms and subjective poor health were similar between regular US and UK Iraq combatants.</p> <p>Conclusion</p> <p>The most common mental disorders in the UK military are alcohol abuse and neurotic disorders. The prevalence of PTSD symptoms remains low in the UK military, but reservists are at greater risk of psychiatric injury than regular personnel.</p

    HLA genotyping in the international Type 1 Diabetes Genetics Consortium

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    Background Although human leukocyte antigen (HLA) DQ and DR loci appear to confer the strongest genetic risk for type 1 diabetes, more detailed information is required for other loci within the HLA region to understand causality and stratify additional risk factors. The Type 1 Diabetes Genetics Consortium (T1DGC) study design included high-resolution genotyping of HLA-A, B, C, DRB1, DQ, and DP loci in all affected sibling pair and trio families, and cases and controls, recruited from four networks worldwide, for analysis with clinical phenotypes and immunological markers

    One year outcomes of a mentoring scheme for female academics: a pilot study at the Institute of Psychiatry, King's College London

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    <p>Abstract</p> <p>Background</p> <p>The professional development of under-represented faculty may be enhanced by mentorship, but we understand very little about the mechanisms by which mentoring brings about change. Our study posed the research question, what are the mechanisms by which mentoring may support professional development in under-represented groups?</p> <p>The study aims to: (i) to pilot a mentoring scheme for female academics; (ii) to compare various health-related and attitudinal measures in mentees at baseline, 6 months, and 1 year into the mentoring relationship and, (iii) to compare pre-mentoring expectations to outcomes at 6 months and 1 year follow-up for mentees and mentors.</p> <p>Methods</p> <p>Female academic mentees were matched 1:1 or 2:1 with more senior academic mentors. Online surveys were conducted to compare health-related and attitudinal measures and expectations of mentoring at baseline with outcomes at 6 months and 1 year using paired t-tests and McNemar's test for matched cohort data.</p> <p>Results</p> <p>N = 46 mentoring pairs, 44 (96%) mentees completed the pre-mentoring survey, 37 (80%) at 6 months and 30 (65%) at 1 year. Job-related well-being (anxiety-contentment), self-esteem and self-efficacy all improved significantly and work-family conflict diminished at 1 year. Highest expectations were career progression (39; 89%), increased confidence (38; 87%), development of networking skills (33; 75%), better time-management (29; 66%) and better work-life balance (28; 64%). For mentees, expectations at baseline were higher than perceived achievements at 6 months or 1 year follow-up.</p> <p>For mentors (N = 39), 36 (92%) completed the pre-mentoring survey, 32 (82%) at 6 months and 28 (72%) at 1 year. Mentors' highest expectations were of satisfaction in seeing people progress (26; 69%), seeing junior staff develop and grow (19; 53%), helping solve problems (18; 50%), helping women advance their careers (18; 50%) and helping remove career obstacles (13; 36%). Overall, gains at 6 months and 1 year exceeded pre-mentoring expectations.</p> <p>Conclusions</p> <p>This uncontrolled pilot study suggests that mentoring can improve aspects of job-related well-being, self-esteem and self-efficacy over 6 months, with further improvements seen after 1 year for female academics. Work-family conflict can also diminish. Despite these gains, mentees' prior expectations were shown to be unrealistically high, but mentors' expectations were exceeded.</p

    Iconic dishes, culture and identity: the Christmas pudding and its hundred years’ journey in the USA, Australia, New Zealand and India

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    Asserting that recipes are textual evidences reflecting the society that produced them, this article explores the evolution of the recipes of the iconic Christmas pudding in the United States, Australia, New Zealand and India between the mid-nineteenth and the mid-twentieth centuries. Combining a micro-analysis of the recipes and the cookbook that provided them with contemporary testimonies, the article observes the dynamics revealed by the preparation and consumption of the pudding in these different societies. The findings demonstrate the relevance of national iconic dishes to the study of notions of home, migration and colonization, as well as the development of a new society and identity. They reveal how the preservation, transformation and even rejection of a traditional dish can be representative of the complex and sometimes conflicting relationships between colonists, migrants or new citizens and the places they live in
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