B Cell Activation and Escape of Tolerance Checkpoints: Recent Insights from Studying Autoreactive B Cells
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Primary Sjogren Syndrome: Focus on Innate Immune Cells and Inflammation
Review Primary Sjogren Syndrome: Focus on Innate Immune Cells and Inflammation Chiara Rizzo 1, Giulia Grasso 1, Giulia Maria Destro Castaniti 1, Francesco Ciccia 2 and Giuliana Guggino 1,* 1 Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, Rheumatology Section, University of Palermo, Piazza delle Cliniche 2, 90110 Palermo, Italy; [email protected] (C.R.); [email protected] (G.G.); [email protected] (G.M.D.C.) 2 Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, Via L. De Crecchio 7, 80138 Naples, Italy; [email protected] * Correspondence: [email protected]; Tel.: +39-091-6552260 Received: 30 April 2020; Accepted: 29 May 2020; Published: 3 June 2020 Abstract: Primary Sjogren Syndrome (pSS) is a complex, multifactorial rheumatic disease that mainly targets salivary and lacrimal glands, inducing epithelitis. The cause behind the autoimmunity outbreak in pSS is still elusive; however, it seems related to an aberrant reaction to exogenous triggers such as viruses, combined with individual genetic pre-disposition. For a long time, autoantibodies were considered as the hallmarks of this disease; however, more recently the complex interplay between innate and adaptive immunity as well as the consequent inflammatory process have emerged as the main mechanisms of pSS pathogenesis. The present review will focus on innate cells and on the principal mechanisms of inflammation connected. In the first part, an overview of innate cells involved in pSS pathogenesis is provided, stressing in particular the role of Innate Lymphoid Cells (ILCs). Subsequently we have highlighted the main inflammatory pathways, including intra- and extra-cellular players. -
Autoimmunity and Organ Damage in Systemic Lupus Erythematosus
REVIEW ARTICLE https://doi.org/10.1038/s41590-020-0677-6 Autoimmunity and organ damage in systemic lupus erythematosus George C. Tsokos ✉ Impressive progress has been made over the last several years toward understanding how almost every aspect of the immune sys- tem contributes to the expression of systemic autoimmunity. In parallel, studies have shed light on the mechanisms that contribute to organ inflammation and damage. New approaches that address the complicated interaction between genetic variants, epigen- etic processes, sex and the environment promise to enlighten the multitude of pathways that lead to what is clinically defined as systemic lupus erythematosus. It is expected that each patient owns a unique ‘interactome’, which will dictate specific treatment. t took almost 100 years to realize that lupus erythematosus, strongly to the heterogeneity of the disease. Several genes linked to which was initially thought to be a skin entity, is a systemic the immune response are regulated through long-distance chroma- Idisease that spares no organ and that an aberrant autoimmune tin interactions10,11. Studies addressing long-distance interactions response is involved in its pathogenesis. The involvement of vital between gene variants in SLE are still missing, but, with the advent organs and tissues such as the brain, blood and the kidney in most of new technologies, such studies will emerge. patients, the vast majority of whom are women of childbearing age, Better understanding of the epigenome is needed to under- impels efforts to develop diagnostic tools and effective therapeu- stand how it supplements the genetic contribution to the dis- tics. The prevalence ranges from 20 to 150 cases per 100,000 peo- ease. -
Pathophysiology of Immune Thrombocytopenic Purpura: a Bird's-Eye View
Egypt J Pediatr Allergy Immunol 2014;12(2):49-61. Review article Pathophysiology of immune thrombocytopenic purpura: a bird's-eye view. Amira Abdel Moneam Adly Pediatrics Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt ABSTRACT and B lymphocytes (including T-helper, T- Immune thrombocytopenic purpura (ITP) is a cytotoxic, and T-regulatory lymphocytes) 6. common autoimmune disorder resulting in isolated The triggering event for ITP is unknown7, but thrombocytopenia. It is a bleeding disorder continued research is providing new insights into characterized by low platelet counts due to decreased the underlying immunopathogenic processes as well platelet production as well as increased platelet as the cellular and molecular mechanisms involved destruction by autoimmune mechanisms. ITP can in megakaryocytopoiesis and platelet turnover. present either alone (primary) or in the setting of other Although historically ITP-associated thrombo- conditions (secondary) such as infections or altered cytopenia was attributed solely to increased rates of immune states. ITP is associated with a loss of destruction of antibody- coated platelets, it has tolerance to platelet antigens and a phenotype of become evident that suboptimal platelet production accelerated platelet destruction and impaired platelet also plays a role 8. production. Although the etiology of ITP remains Bleeding is due to decreased platelet production unknown, complex dysregulation of the immune as well as accelerated platelet destruction mediated system is observed in ITP patients. Antiplatelet in part by autoantibody-based destruction antibodies mediate accelerated clearance from the mechanisms9. Most autoantibodies in ITP are circulation in large part via the reticuloendothelial isotype switched and harbor somatic mutations10, (monocytic phagocytic) system. -
Case of the Anti HIV-1 Antibody, B12
Spectrum of Somatic Hypermutations and Implication on Antibody Function: Case of the anti HIV-1 antibody, b12 Mesfin Mulugeta Gewe A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Washington 2015 Reading Committee: Roland Strong, Chair Nancy Maizels Jessica A. Hamerman Program Authorized to Offer Degree: Molecular and Cellular Biology i ii ©Copyright 2015 Mesfin Mulugeta Gewe iii University of Washington Abstract Spectrum of Somatic Hypermutations and Implication on Antibody Function: Case of the anti HIV-1 antibody, b12 Mesfin Mulugeta Gewe Chair of the Supervisory Committee: Roland Strong, Full Member Fred Hutchinson Cancer Research Center Sequence diversity, ability to evade immune detection and establishment of human immunodeficiency virus type 1 (HIV-1) latent reservoirs present a formidable challenge to the development of an HIV-1 vaccine. Structure based vaccine design stenciled on infection elicited broadly neutralizing antibodies (bNAbs) is a promising approach, in some measure to circumvent existing challenges. Understanding the antibody maturation process and importance of the high frequency mutations observed in anti-HIV-1 broadly neutralizing antibodies are imperative to the success of structure based vaccine immunogen design. Here we report a biochemical and structural characterization for the affinity maturation of infection elicited neutralizing antibodies IgG1 b12 (b12). We investigated the importance of affinity maturation and mutations accumulated therein in overall antibody function and their potential implications to vaccine development. Using a panel of point iv reversions, we examined relevance of individual amino acid mutations acquired during the affinity maturation process to deduce the role of somatic hypermutation in antibody function. -
Overview of B-Cell Maturation, Activation, Differentiation
Overview of B-Cell Maturation, Activation, Differentiation B-Cell Development Begins in the Bone Marrow and Is Completed in the Periphery Antigen-Independent (Maturation) 1) Pro-B stages B-cell markers 2) Pre B-stages H- an L- chain loci rearrangements surrogate light chain 3) Naïve B-cell functional BCR . B cells are generated in the bone marrow. Takes 1-2 weeks to develop from hematopoietic stem (HSC) cells to mature B cells. Sequence of expression of cell surface receptor and adhesion molecules which allows for differentiation of B cells, proliferation at various stages, and movement within the bone marrow microenvironment. HSC passes through progressively more delimited progenitor-cell stages until it reaches the pro-B cell stage. Pre-B cell is irreversibly committed to the B-cell lineage and the recombination of the immunoglobulin genes expressed on the cell surface Immature B cell (transitional B cell) leaves the bone marrow to complete its maturation in the spleen through further differentiation. Immune system must create a repertoire of receptors capable of recognizing a large array of antigens while at the Source: Internet same time eliminating self-reactive B cells. B-Cell Activation and Differentiation • Exposure to antigen or various polyclonal mitogens activates resting B cells and stimulates their proliferation. • Activated B cells lose expression of sIgD and CD21 and acquire expression of activation antigens. Growth factor receptors, structures involved in cell-cell interaction, molecules that play a role in the localization and binding of activated B cells Two major types: T cell dependent (TD) T cell independent (TI) B-Cell Activation by Thymus-Independent and Dependent Antigens Source: Kuby T cell dependent: Involves protein antigens and CD4+ helper T cells. -
Mechanisms Governing Anaphylaxis: Inflammatory Cells, Mediators
International Journal of Molecular Sciences Review Mechanisms Governing Anaphylaxis: Inflammatory Cells, Mediators, Endothelial Gap Junctions and Beyond Samantha Minh Thy Nguyen 1, Chase Preston Rupprecht 2, Aaisha Haque 3, Debendra Pattanaik 4, Joseph Yusin 5 and Guha Krishnaswamy 1,3,* 1 Department of Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27106, USA; [email protected] 2 The Rowan School of Osteopathic Medicine, Stratford, NJ 08084, USA; [email protected] 3 The Bill Hefner VA Medical Center, Salisbury, NC 27106, USA; [email protected] 4 Division of Allergy and Immunology, UT Memphis College of Medicine, Memphis, TN 38103, USA; [email protected] 5 The Division of Allergy and Immunology, Greater Los Angeles VA Medical Center, Los Angeles, CA 90011, USA; [email protected] * Correspondence: [email protected] Abstract: Anaphylaxis is a severe, acute, life-threatening multisystem allergic reaction resulting from the release of a plethora of mediators from mast cells culminating in serious respiratory, cardiovascular and mucocutaneous manifestations that can be fatal. Medications, foods, latex, exercise, hormones (progesterone), and clonal mast cell disorders may be responsible. More recently, novel syndromes such as delayed reactions to red meat and hereditary alpha tryptasemia have been described. Anaphylaxis manifests as sudden onset urticaria, pruritus, flushing, erythema, Citation: Nguyen, S.M.T.; Rupprecht, angioedema (lips, tongue, airways, periphery), myocardial dysfunction (hypovolemia, distributive -
B-Cell Reconstitution Recapitulates B-Cell Lymphopoiesis Following Haploidentical BM Transplantation and Post-Transplant CY
Bone Marrow Transplantation (2015) 50, 317–319 © 2015 Macmillan Publishers Limited All rights reserved 0268-3369/15 www.nature.com/bmt LETTER TO THE EDITOR B-cell reconstitution recapitulates B-cell lymphopoiesis following haploidentical BM transplantation and post-transplant CY Bone Marrow Transplantation (2015) 50, 317–319; doi:10.1038/ From week 9, the proportion of transitional B cells progressively bmt.2014.266; published online 24 November 2014 decreased (not shown), whereas that of mature B cells increased (Figure 1d). To further evaluate the differentiation of mature cells, we included markers of naivety (IgM and IgD) and memory (IgG) in The treatment of many hematological diseases benefits from our polychromatic panel. At week 9, when a sufficient proportion myeloablative or non-myeloablative conditioning regimens of cells were available for the analysis, B cells were mostly naive followed by SCT or BMT. HLA-matched donors are preferred but and remained so for 26 weeks after haploBMT (Figure 1d). Despite not always available. Instead, haploidentical donors can be rapidly low, the proportion of memory B cells reached levels similar to identified. Unmanipulated haploidentical BMT (haploBMT) with that of marrow donors (Supplementary Figure 1D). non-myeloablative conditioning and post-transplant Cy has been To further investigate the steps of B-cell maturation, we developed to provide a universal source of BM donors.1 Cy, analyzed CD5, a regulator of B-cell activation, and CD21, a which depletes proliferating/allogeneic cells, prevents GVHD.1 component of the B-cell coreceptor complex, on transitional B Importantly, the infection-related mortality was remarkably low, cells. These surface markers characterize different stages of 5,6 5,6 suggesting effective immune reconstitution.1,2 However, a transitional B-cell development. -
Human B Cell Isolation Product Selection Diagram
Human B Cell Isolation Product Selection Explore the infographic below to find the correct human B cell isolation product for your application. 1. Your Starting Sample Whole Peripheral Blood/Buffy Coat PBMCs/Leukapheresis Pack 2. Cell Separation Platform Immunodensity Cell Separation Immunomagnetic Cell Separation Immunomagnetic Cell Separation 3. Product Line RosetteSep™ EasySep™ EasySep™ Sequential Selection Negative Selection Negative Selection Positive Selection Negative Selection Positive Selection 4. Selection Method (Positive + Negative) iRosetteSep™ HLA iEasySep™ Direct HLA i, iiEasySep™ HLA iEasySep™ HLA B Cell viEasySep™ Human CD19 EasySep™ Human IgG+ B Cell Enrichment Cocktail B Cell Isolation Kit Chimerism Whole Blood Enrichment Kit Positive Selection Kit II Memory B Cell Isolation (15064HLA)1, 2, 3 (89684) / EasySep™ Direct B Cell Positive Selection (19054HLA)1, 2 (17854)1, 2 Kit (17868)1 (optional), 2' HLA Crossmatch B Cell Kit (17886)1, 2 Isolation Kit (19684 - 1, 2 RosetteSep™ Human available in the US only) iiiEasySep™ Human B Cell viEasySep™ Release EasySep™ Human Memory 5. Cell Isolation Kits B Cell Enrichment Cocktail i, iiEasySep™ HLA Enrichment Kit Human CD19 Positive B Cell Isolation Kit 1, 2, 3 1, 2 1, 2 1 (optional), 2 Catalog #s shown in ( ) (15024) Chimerism Whole Blood (19054) Selection Kit (17754) (17864) EasySep™ Direct Human CD19 Positive Selection B-CLL Cell Isolation Kit Kit (17874)1, 2 1, 2, 3, 4 *RosetteSep™ Human (19664) iiiEasySep™ Human B Cell EasySep™ Human CD138 Multiple Myeloma Cell Isolation Kit -
Of T Cell Tolerance
cells Review Strength and Numbers: The Role of Affinity and Avidity in the ‘Quality’ of T Cell Tolerance Sébastien This 1,2,† , Stefanie F. Valbon 1,2,†, Marie-Ève Lebel 1 and Heather J. Melichar 1,3,* 1 Centre de Recherche de l’Hôpital Maisonneuve-Rosemont, Montréal, QC H1T 2M4, Canada; [email protected] (S.T.); [email protected] (S.F.V.); [email protected] (M.-È.L.) 2 Département de Microbiologie, Immunologie et Infectiologie, Université de Montréal, Montréal, QC H3C 3J7, Canada 3 Département de Médecine, Université de Montréal, Montréal, QC H3T 1J4, Canada * Correspondence: [email protected] † These authors contributed equally to this work. Abstract: The ability of T cells to identify foreign antigens and mount an efficient immune response while limiting activation upon recognition of self and self-associated peptides is critical. Multiple tolerance mechanisms work in concert to prevent the generation and activation of self-reactive T cells. T cell tolerance is tightly regulated, as defects in these processes can lead to devastating disease; a wide variety of autoimmune diseases and, more recently, adverse immune-related events associated with checkpoint blockade immunotherapy have been linked to a breakdown in T cell tolerance. The quantity and quality of antigen receptor signaling depend on a variety of parameters that include T cell receptor affinity and avidity for peptide. Autoreactive T cell fate choices (e.g., deletion, anergy, regulatory T cell development) are highly dependent on the strength of T cell receptor interactions with self-peptide. However, less is known about how differences in the strength Citation: This, S.; Valbon, S.F.; Lebel, of T cell receptor signaling during differentiation influences the ‘function’ and persistence of anergic M.-È.; Melichar, H.J. -
How Does Protein Zero Assemble Compact Myelin?
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 13 May 2020 doi:10.20944/preprints202005.0222.v1 Peer-reviewed version available at Cells 2020, 9, 1832; doi:10.3390/cells9081832 Perspective How Does Protein Zero Assemble Compact Myelin? Arne Raasakka 1,* and Petri Kursula 1,2 1 Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway 2 Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Aapistie 7A, FI-90220 Oulu, Finland; [email protected] * Correspondence: [email protected] Abstract: Myelin protein zero (P0), a type I transmembrane protein, is the most abundant protein in peripheral nervous system (PNS) myelin – the lipid-rich, periodic structure that concentrically encloses long axonal segments. Schwann cells, the myelinating glia of the PNS, express P0 throughout their development until the formation of mature myelin. In the intramyelinic compartment, the immunoglobulin-like domain of P0 bridges apposing membranes together via homophilic adhesion, forming a dense, macroscopic ultrastructure known as the intraperiod line. The C-terminal tail of P0 adheres apposing membranes together in the narrow cytoplasmic compartment of compact myelin, much like myelin basic protein (MBP). In mouse models, the absence of P0, unlike that of MBP or P2, severely disturbs the formation of myelin. Therefore, P0 is the executive molecule of PNS myelin maturation. How and when is P0 trafficked and modified to enable myelin compaction, and how disease mutations that give rise to incurable peripheral neuropathies alter the function of P0, are currently open questions. The potential mechanisms of P0 function in myelination are discussed, providing a foundation for the understanding of mature myelin development and how it derails in peripheral neuropathies. -
B Cell Checkpoints in Autoimmune Rheumatic Diseases
REVIEWS B cell checkpoints in autoimmune rheumatic diseases Samuel J. S. Rubin1,2,3, Michelle S. Bloom1,2,3 and William H. Robinson1,2,3* Abstract | B cells have important functions in the pathogenesis of autoimmune diseases, including autoimmune rheumatic diseases. In addition to producing autoantibodies, B cells contribute to autoimmunity by serving as professional antigen- presenting cells (APCs), producing cytokines, and through additional mechanisms. B cell activation and effector functions are regulated by immune checkpoints, including both activating and inhibitory checkpoint receptors that contribute to the regulation of B cell tolerance, activation, antigen presentation, T cell help, class switching, antibody production and cytokine production. The various activating checkpoint receptors include B cell activating receptors that engage with cognate receptors on T cells or other cells, as well as Toll-like receptors that can provide dual stimulation to B cells via co- engagement with the B cell receptor. Furthermore, various inhibitory checkpoint receptors, including B cell inhibitory receptors, have important functions in regulating B cell development, activation and effector functions. Therapeutically targeting B cell checkpoints represents a promising strategy for the treatment of a variety of autoimmune rheumatic diseases. Antibody- dependent B cells are multifunctional lymphocytes that contribute that serve as precursors to and thereby give rise to acti- cell- mediated cytotoxicity to the pathogenesis of autoimmune diseases -
B Lymphocytes in Neuromyelitis Optica
VIEWS & REVIEWS B lymphocytes in neuromyelitis optica Jeffrey L. Bennett, MD, ABSTRACT PhD Neuromyelitis optica (NMO) is an inflammatory autoimmune disorder of the CNS that predomi- ’ Kevin C. O Connor, PhD nantly affects the spinal cord and optic nerves. A majority (approximately 75%) of patients with Amit Bar-Or, MD, FRCP NMO are seropositive for autoantibodies against the astrocyte water channel aquaporin-4 Scott S. Zamvil, MD, (AQP4). These autoantibodies are predominantly IgG1, and considerable evidence supports their PhD pathogenicity, presumably by binding to AQP4 on CNS astrocytes, resulting in astrocyte injury Bernhard Hemmer, MD and inflammation. Convergent clinical and laboratory-based investigations have indicated that Thomas F. Tedder, PhD B cells play a fundamental role in NMO immunopathology. Multiple mechanisms have been H.-Christian von hypothesized: AQP4 autoantibody production, enhanced proinflammatory B cell and plasmablast Büdingen, MD activity, aberrant B cell tolerance checkpoints, diminished B cell regulatory function, and loss of Olaf Stuve, MD, PhD B cell anergy. Accordingly, many current off-label therapies for NMO deplete B cells or modulate Michael R. Yeaman, PhD their activity. Understanding the role and mechanisms whereby B cells contribute to initiation, Terry J. Smith, MD maintenance, and propagation of disease activity is important to advancing our understanding Christine Stadelmann, of NMO pathogenesis and developing effective disease-specific therapies. Neurol Neuroimmunol MD Neuroinflamm 2015;2:e104;