1,470 research outputs found

    Impact of SARS-CoV-2 infection and COVID-19 on patients with inborn errors of immunity

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    : Since the arrival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019, its characterization as a novel human pathogen, and the resulting coronavirus disease 2019 (COVID-19) pandemic, over 6.5 million people have died worldwide-a stark and sobering reminder of the fundamental and nonredundant roles of the innate and adaptive immune systems in host defense against emerging pathogens. Inborn errors of immunity (IEI) are caused by germline variants, typically in single genes. IEI are characterized by defects in development and/or function of cells involved in immunity and host defense, rendering individuals highly susceptible to severe, recurrent, and sometimes fatal infections, as well as immune dysregulatory conditions such as autoinflammation, autoimmunity, and allergy. The study of IEI has revealed key insights into the molecular and cellular requirements for immune-mediated protection against infectious diseases. Indeed, this has been exemplified by assessing the impact of SARS-CoV-2 infection in individuals with previously diagnosed IEI, as well as analyzing rare cases of severe COVID-19 in otherwise healthy individuals. This approach has defined fundamental aspects of mechanisms of disease pathogenesis, immunopathology in the context of infection with a novel pathogen, and therapeutic options to mitigate severe disease. This review summarizes these findings and illustrates how the study of these rare experiments of nature can inform key features of human immunology, which can then be leveraged to improve therapies for treating emerging and established infectious diseases

    Activated PI3Kδ breaches multiple B cell tolerance checkpoints and causes autoantibody production

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    Antibody-mediated autoimmune diseases are a major health burden. However, our understanding of how self-reactive B cells escape self-tolerance checkpoints to secrete pathogenic autoantibodies remains incomplete. Here, we demonstrate that patients with monogenic immune dysregulation caused by gain-of-function mutations in PIK3CD, encoding the p110δ catalytic subunit of phosphoinositide 3-kinase (PI3K), have highly penetrant secretion of autoreactive IgM antibodies. In mice with the corresponding heterozygous Pik3cd activating mutation, self-reactive B cells exhibit a cell-autonomous subversion of their response to self-antigen: instead of becoming tolerized and repressed from secreting autoantibody, Pik3cd gain-of-function B cells are activated by self-antigen to form plasmablasts that secrete high titers of germline-encoded IgM autoantibody and hypermutating germinal center B cells. However, within the germinal center, peripheral tolerance was still enforced, and there was selection against B cells with high affinity for self-antigen. These data show that the strength of PI3K signaling is a key regulator of pregerminal center B cell self-tolerance and thus represents a druggable pathway to treat antibody-mediated autoimmunity.sponsorship: This work was supported by National Health and Medical Research Council (NHMRC) program grants (1016953 and 1113904 to S.G. Tangye, R. Brink, and C.C. Goodnow), NHMRC project grants (1088215 to E.K. Deenick; 1127157 to S.G. Tangye and E.K. Deenick), NHMRC Principal Research Fellowships (1042925 to S.G. Tangye; 1105877 to R. Brink), a Fulbright Senior Scholarship (to S.G. Tangye), the Office of Health and Medical Research of the New South Wales Government, the Jeffrey Modell Foundation, the John Brown Cook Foundation, the Ross Trust, and a Bench-to-Bedside grant from the National Institute of Allergy and Infectious Diseases, National Institutes of Health. G. Uzel and L.D. Notarangelo are supported by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health. (National Health and Medical Research Council (NHMRC)|1016953, National Health and Medical Research Council (NHMRC)|1113904, NHMRC|1088215, NHMRC|1127157, NHMRC|1042925, NHMRC|1105877, Fulbright Senior Scholarship, Office of Health and Medical Research of the New South Wales Government, Jeffrey Modell Foundation, John Brown Cook Foundation, Ross Trust, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, National Institute of Allergy and Infectious Diseases|ZIAAI001222, National Health and Medical Research Council of Australia|1088215, National Health and Medical Research Council of Australia|1127157, National Health and Medical Research Council of Australia|1105877)status: Publishe

    Redemption in the work of Francis Stuart

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    The idea of redemption is central to an understanding of the work of Francis Stuart. Through an examination of its development and expression, it is possible to demonstrate the integrity of his work and its distinctive qualities. Such a demonstration is necessary because Stuart's writing has been subjected to comparatively little scholarly inquiry, although reviews of his work, especially that produced since 1949, suggest that it is impressive and important. First, a general background to Stuart's work, a discussion of the special problems associated with reading it, and a summary of his corpus is provided. This indicates that the idea of redemption is important to his earliest writing. The state of redemption is shown to be a necessary apotheosis for Stuart's outcast heroes; it involves spiritual suffering through which may be found a sense of reintegration and a higher reality. This is expressed through interrelated themes such as those of gambler, artist and ordinary man; mystic and criminal; sacred and profane love; and spirituality and the mundane. The nature of the redemptive experience is further elaborated by distinctive, complex motifs, especially the hare, the ark and the woman-Christ. Their recurrence provides an important element in the unity of Stuart's work. Because Stuart's idea of the outcast raises important biographical questions, an examination of the relationship between Stuart's life and his work is made. Finally, the way in which the idea of redemption exists in the language structures of Stuart's novels is examined, with especial reference to his most recent work, The High Consistory. The thesis shows that the development of the these of redemption demonstrates the integrity of Stuart's work

    John Stuart Mill’s projected science of society: 1827-1848

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    The purpose of the thesis is to examine John Stuart Mill’s political thought from about 1827 to 1848 as an exercise in intellectual history. It focuses, first, on Mill’s view, formulated by the late 1830s, that contemporary society was ‘civilized’, and second, on his project of a science of society, which he aspired to develop in the late 1830s and early 1840s. By the late 1830s, Mill came to the view that his contemporary society was a ‘commercial society or civilization’, dominated by the middle, commercial class. The first part of my thesis, constituted by Chapters 2-4, discusses the way in which Mill formed his notion of civilization, and what he meant by the term ‘civilization’. Mill paid attention to the implications of the rise of the middle class, and regarded such phenomena of contemporary society as the corruption of the commercial spirit and excessive social conformity as an inevitable consequence of the rise of the middle class. The second part of the thesis, constituted by Chapters 5-9, examines Mill’s projected science of society. In the late 1830s and early 1840s, Mill attempted to develop a new science of society whose subject-matter was the nature and prospects of commercial, civilized society. This aspiration culminated in A System of Logic, published in 1843. In examining Mill’s projected science, I pay particular attention to the fact that he conceived new sciences of history and of the formation of character, both of which were indispensable in his project, although he failed to give a complete account of these sciences. My thesis shows that the implications of his interest both in history and in the formation of character are more significant than Mill scholars have assumed

    Plasmacytoid DCs Induce Gutsy Plasma Cells

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    Immunoglobulin (Ig) A is critical for protective immune responses at mucosal surfaces. In this issue of Immunity, Tezuka et al. (2011) identify an important relay between stromal cells and plasmacytoid dendritic cells that regulates IgA production by murine B cells

    Cytokine-mediated regulation of plasma cell generation: IL-21 takes center stage

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    During our life we are surrounded by continuous threats from a diverse range of invading pathogens. Our immune system has evolved multiple mechanisms to efficiently deal with these threats to prevent them causing disease. Differentiation of mature B cells into plasma cells (PC) - the antibody (Ab) secreting cells of the immune system - is critical for the generation of protective and long-lived humoral immune responses. Indeed, efficient production of antigen (Ag)-specific Ab underlies the success of most currently available vaccines. The mature B cell pool is composed of several subsets, distinguished from one according to size, surface marker expression, location and Ag exposure, and they all have the capacity to differentiate into PCs. For a B cell to acquire the capacity to produce Abs, it must undergo an extensive differentiation process driven by changes in gene expression. Two broad categories of Ag exist that cause B cell activation and differentiation: T cell dependent (TD) or T cell independent (TI). In addition to the B cell subset and nature of the Ag, it is important to consider the cytokine environment that also influences how B cell differentiation is achieved. Thus, while many cytokines can induce Ab secretion by B cells after activation with mimics of TD and TI stimuli in vitro, they can have different efficacies and specificities, and can often preferentially induce production of one Ig isotype over another. Here, we will provide an overview of in vitro studies (mouse and human origin) that evaluated the role the different cytokines in inducing the differentiation of distinct B cell subsets to the PC lineage. We will place particular emphasis on IL-21, which has emerged as the most potent inducer of terminal B cell differentiation in humans. We will also focus on the role of IL-21 and defects in B-cell function and how these contribute to human immunopathologies such as primary immunodeficiencies and B-cell mediated autoimmune conditions

    T cells require DOCK8 for flexibility and function

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