Medical Sciences Commons^™

The Immunoregulation Of Autoimmune Diabetes, Hao Hu

Arts & Sciences Electronic Theses and Dissertations

How autoimmune diseases are regulated is a long-term research topic in the autoimmunity field. We use autoimmune diabetes as a model to study this. Autoimmune diabetes is a T cell-dependent autoimmune syndrome. The functions of T cells are regulated during their development and activation. Developmentally, T cells will undergo a stringent thymic selection: a process that self-reactive T cells are tolerized to become thymic derived Tregs or can be deleted by apoptosis based on binding affinity and avidity between the TCRs and self-peptide:MHC complexes. After T cells mature, they can also be tolerized in the periphery in many other ways, …

Regulation Of Host-Microbe Interactions In Autoimmunity And Antiviral Immunity By Cytosolic Nucleic Acid Sensing And Interferon Signaling, Derek Jerome Platt

Arts & Sciences Electronic Theses and Dissertations

Cytosolic nucleic acid sensing and interferon (IFN) signaling are central to the host immune response to microbial pathogens. However, dysregulation of immunological pathways such as these can result in devastating autoimmune disease. In order to provide a robust immune response to pathogen without causing harm to self, the host immune system must engage in a delicate balancing act, interacting with microbes and determining whether they are commensal or pathogenic. The cGAS-STING pathway is a key regulator of host-microbe interactions by cytosolic nucleic sensing and IFN signaling. Loss of function in the cGAS-STING pathway leads to increased susceptibility to pathogenic threats, …

Investigation Of Ifnγ-Induced Control Of Intracellular Pathogens, Michael Mcallaster

Arts & Sciences Electronic Theses and Dissertations

Genes required for the lysosomal degradation pathway of autophagy play key roles in topologically distinct cellular processes with significant physiologic importance. One of the first-described of these ATG gene-dependent processes is the requirement for a subset of ATG genes in interferon-γ (IFNγ)-induced inhibition of norovirus and Toxoplasma gondii replication. In this dissertation we identified novel components that are required for or that negatively regulate this immune mechanism. Enzymes involved in the conjugation of UFM1 to target proteins including UFC1 and UBA5, negatively regulated IFNγ-induced inhibition of norovirus replication via effects of Ern1. We identified and confirmed that IFNγ-induced inhibition of …

Metabolic Control And Immune Barriers Of Hematopoietic Stem Cells, Hannah Pizzato

Arts & Sciences Electronic Theses and Dissertations

Hematopoietic stem cells (HSCs) have the unique ability to self-renew for life, to differentiate into mature blood lineages, and to readily engraft upon intravenous transplantation. As such, they are the only types of stem cells in routine clinical use. Understanding HSCs and hematopoietic development can provide many lessons for other types of stem cells as they near clinical utility. Through bone marrow transplantation, it was discovered that cells exist with regenerative potential. This led to the search to purify these cells and to determine the function of other hematopoietic cells. By isolating and transplanting cells expressing different combinations of surface …

Uncovering A Myc-Driven Tumor-Suppressive Program In Proliferating Lymphocytes, Elena Tonc

Arts & Sciences Electronic Theses and Dissertations

Rapid cell proliferation is a hallmark feature of adaptive immune cells lymphocytes. It is essential for the establishment of diverse antigen receptor repertoires and amplification of antigen-specific immune responses. While such proliferation is beneficial for host protection from infections and cancers, it inevitably elevates the risk of oncogenic transformation. In developing and germinal center B lymphocytes, the risk is further increased by endogenous, genomic insults due to antigen receptor rearrangements and somatic mutations, with which expression of the proto-oncogene c-MYC is closely associated. Nonetheless, frequencies of cancers originated from B lymphocytes are relatively low, suggesting that they are protected from …

Peripheral Nerve Macrophages And Their Implications In Neuroimmunity, Peter Leon Wang

Arts & Sciences Electronic Theses and Dissertations

Macrophages are innate immune cells that protect against pathogens and maintain tissue integrity. In vertebrates, macrophages reside in every tissue where they perform specific functions from early development through adulthood. While macrophages provide important functions across all tissues, a major focus in recent years has been the role of resident brain macrophages, known as microglia, in neurodegeneration. As microglia have been shown to affect brain development, homeostasis, and disease, they demonstrate how immune cells critically mediate neurological health and point to the broader significance of neuroimmune interactions, or the coordinated actions of the nervous and immune systems for maintaining tissue …

Investigating The Role Of Bladder Epithelial Stem Cells In Bladder Mucosal Remodeling And Defense Against Infection, Seongmi Kim Russell

Arts & Sciences Electronic Theses and Dissertations

Urinary tract infections (UTIs) can be highly recurrent, and the mechanism(s) governing recurrence susceptibility are mostly unknown. Here I demonstrate bladder epithelial (urothelial)-intrinsic trained immunity as part of a differential mucosal remodeling response to an initial UTI. I established urothelial stem cell (USC) lines from isogenic mice with different UTI histories (naïve, chronic, or self-resolving) and discovered 2880 differential genome-accessible regions, indicating differential epigenetic reprogramming dependent on infection history. Differentiation of USC lines in vitro resulted in polarized urothelial cultures that recapitulated distinct remodeling morphologies seen in vivo and exhibited altered gene expression, including genes involved in cell death pathways. …

Mechanisms Of Natural Killer Cell Anti-Tumor Function And Homeostasis, Julia Alexandra Wagner

Arts & Sciences Electronic Theses and Dissertations

Natural killer (NK) cells are innate lymphoid cells (ILCs) that mediate anti-tumor and anti-viral immune responses. They do so via two primary effector functions: cytokine production and direct cytotoxicity. Unlike adaptive T and B lymphocytes, NK cells do not rearrange their DNA to express a predominant antigen-specific receptor, and instead express a variety of stochastically-expressed, germline DNA-encoded activating and inhibitory receptors whose signals integrate to govern their functional responses. What results is a diverse repertoire of NK cells capable of recognizing a variety of malignantly-transformed or virally-infected cells. Studies from several groups have established the anti-tumor potential of NK cells, …

Transcriptional Control Of Dendritic Cell Function And Development, David Alexander Anderson Iii

Arts & Sciences Electronic Theses and Dissertations

Dendritic cells (DCs) are innate immune cells of the myeloid lineage that are specialized at pathogen recognition, cytokine production, and antigen presentation. Their functions and developmental pathways are largely conserved between mice and humans and mice. The DC lineage is composed of two major subsets, known as plasmacytoid DCs (pDCs) and classical DCs (cDCs). Research conducted to date suggests that the function of pDCs, limited to viral antigen recognition and type I interferon production, can be compensated by other immune cell lineages. On the other hand, there is a consensus that diversified subsets cDCs in mice and humans are essential …

Dissecting The Role And Regulation Of Transcription Factor Zeb2 In Hematopoiesis, Xiao Huang

Arts & Sciences Electronic Theses and Dissertations

A potent immune response requires crosstalk and collaboration between the innate and adaptive immune systems, both of which contain highly specialized immune lineages. All immune lineages arise during adult life are generated from the differentiation of hematopoietic stem cells (HSCs) in the process of hematopoiesis. Normal hematopoiesis under steady state and emergency hematopoiesis during immune response are orchestrated precisely by transcriptional networks formed by transcription factors (TFs) to direct multipotent progenitors into specific fate. TFs required for the development of single or multiple lineages within the hematopoietic system has been identified, such as Irf8 for type I classical dendritic cells …

The Roles Of Capsular Polysaccharides And Diet In The Immune Response To A Bacteroides Thetaiotaomicron Antigen, Samantha Hsieh

Arts & Sciences Electronic Theses and Dissertations

The environment is well recognized to modulate immune responses within the intestinal mucosa in a general fashion. However, the connection between the effects of the environment on the immune response directed towards specific intestinal microbes is unclear. Progress in this area has been hampered by the lack of a model system in which the immune responses to a specific antigen in a gut symbiont can be examined. To this end, we developed a novel CD4+ T cell model, termed BθOM, that is specific for a dominant antigen in the gut symbiont Bacteroides thetaiotaomicron (B. theta). In this work, we use …

A Novel Function Of Plasmacytoid Dendritic Cells In Regulating Type 2 Immune Responses, Hannah Leigh Miller

Arts & Sciences Electronic Theses and Dissertations

The generation of an allergic response is particularly perplexing, as the mucosal immune system is exposed to a myriad of antigens on a daily basis, the majority of which do not elicit inflammation. However, for the growing population of patients impacted by allergic diseases, there is a clear breakdown of normal tolerance to innocuous antigens, resulting in symptoms mediated by antigen specific T helper 2 (Th2) cells. In addition to their well-established role in early antiviral immunity via production of type I interferon, plasmacytoid dendritic cells (pDC) have been implicated in the generation of immune tolerance in a variety of …

Regulation Of Gut Commensal-Specific T Cell Differentiation By Dendritic Cell Subsets, Emilie Russler-Germain

Arts & Sciences Electronic Theses and Dissertations

The mammalian gastrointestinal tract can harbor both beneficial commensal organisms important for host health, but also pathogenic organisms capable of intestinal damage. It is therefore important that the host immune system mounts appropriate responses to different intestinal organisms – promoting tolerance to some, controlling the colonization of others, and inducing sterilizing immunity in cases of noxious pathogens. Failure to induce tolerance to commensal organisms may underlie immune-mediated diseases such as human inflammatory bowel disease, while inappropriate tolerance to more harmful organisms has the potential to result in infection, inflammation, or even malabsorption. Adaptive immune responses to intestinal commensal organisms are …

Etv2/Myct1 Axis In The Regulation Of Tumor Angiogenesis And Anti-Tumor Immunity, Ashraf Ul Kabir

Arts & Sciences Electronic Theses and Dissertations

Angiogenesis is a critical determinant of neoplastic growth and metastatic spread. As such, anti-angiogenic approaches have long been tried to throttle down tumor progression. However, current anti-angiogenic treatments so far have produced modest clinical benefits. Further in-depth research has provided rationales behind these disappointing and apparent perplexing clinical outcomes. It is now established that VEGF (vascular endothelial growth factor) and other prominent current angiogenic targets are neither specific to the vascular system nor the pathological conditions explaining the sub-optimal angiogenic control following the existing treatments. This suggests that anti-angiogenesis could still be a viable strategy for cancer patients should there …

Glial Inflammatory Responses Regulate Neurocognitive Recovery Following Viral Encephalitis, Allison Luen Soung

Arts & Sciences Electronic Theses and Dissertations

The concept of the brain as an immune privileged organ has been slowly shifting as an in-creasing number of studies have demonstrated that even under homeostatic conditions, commu-nication between the nervous and immune system is essential for proper brain function. Given their roles in innate and adaptive immunity, glial cells and infiltrating immune cells have been placed at the center of this communication axis. Microglia, astrocytes, and T cells have all been shown to receive and convey information to all neural cell types in a coordinated effort to re-spond to injury and infection and initiate reparative mechanisms as well as …

Homeostatic T Cell Receptor Interactions With Self-Peptide Tune Cd4+ T Cell Function, Juliet Marie Bartleson

Arts & Sciences Electronic Theses and Dissertations

Homeostatic T Cell Receptor Interactions with Self-Peptide Tune CD4+ T Cell Function

by

Juliet Marie Bartleson

Doctor of Philosophy in Biology and Biomedical Sciences

Immunology

Washington University in St. Louis, 2021

Professor Paul M. Allen, Chair

Mature CD4+ T cells circulate throughout peripheral secondary lymphoid organs using their T cell receptor (TCR) to surveil peptide presented on major histocompatibility complex class II molecules (pMHC) in search of cognate, antigenic peptide. In the absence of an immune challenge, however, the TCR is continuously interacting with self-pMHC, which induces a relatively weak TCR signal known as tonic signaling. These homeostatic TCR:self-pMHC interactions …

Examining Early Interactions Between Innate Airway Resident Immune Cells And Mtb-Specific Factors During Pulmonary Infection With Mycobacterium Tuberculosis, Micah D. Dunlap

Arts & Sciences Electronic Theses and Dissertations

Mycobacterium tuberculosis (Mtb) is the leading cause of death by an infectious agent in the world today, infecting roughly one quarter of humans. Despite this, the mechanisms of early pathogenesis and host protective innate immune responses remain poorly understood and uncharacterized.

Lung resident Alveolar Macrophages (AMs) are the first host contact with Mtb bacilli after inhalation and are thus key mediators of the early pulmonary immune response. AMs are generally believed to reside entirely in the airway, but it was recently demonstrated that they have the capacity to egress and enter into granulomas during pulmonary infection with hypervirulent Mtb. Furthermore, …