Immunology and Infectious Disease Commons^™

The Characterization Of Rna Content And Biogenesis Pathways Of Extracellular Vesicles That Have Been Implicated In The Pathogenesis Of Hiv-1 Associated Neurocognitive Disorders, Virginia Elizabeth Zwikelmaier

Master's Theses

Patients infected with HIV-1 adhering to Anti-Retroviral Therapy (ART) still suffer from a variety of neurocognitive, behavioral, and motor dysfunctions, collectively referred to has HIV-1 Associated Neurocognitive Disorders (HAND). Current research suggests the manifestations of HAND might in part be due to the dissemination of toxic HIV-1 components throughout the brain via extracellular vesicles (EVs). Our goal is to characterize these pathogenic EVs to begin to gain a better understanding of this EV-mediated pathology.

We took the first steps in developing a technique to assess the microRNA content of individual EVs but it needs to be heavily optimized to eliminate …

Lidocaine Attenuates An Induced Inflammatory Response, Stephanie Zack

Master's Theses

Inflammation is common to the pathogenesis of a variety of diseases. Therapeutics which can regulate and reduce damaging inflammation are therefore valuable in the treatment of inflammation and inflammatory diseases.

One commonly used analgesic, recently identified as limiting inflammation, is lidocaine. Additionally, alternative, less toxic therapeutics like the snake venom peptides, Zep 3 and Zep 4, are thought to have anti-inflammatory effects. Yet a well-defined mechanism or cellular target for lidocaine or Zep peptides' anti-inflammatory effects has not been proposed.

We aimed to determine whether lidocaine and Zep peptides reduce the release of the proinflammatory cytokine, IL-1β, from activated human …

The Novel Characterization Of Extracellular Vesicles Containing Proteins Which Have Been Implicated In The Pathogenesis Of Hiv Associated Neurocognitive Disorders, Grace Ispas

Master's Theses

Although Anti-Retroviral Therapy (ART) is practiced, HIV-1 positive individuals still experience HIV-Associated Neurocognitive Disorders (HAND), collectively described as the presentation of neurocognitive, behavioral and motor dysfunctions that decrease the quality of life, while increasing the mortality in ART suppressed HIV-1 positive patients.

Current literature suggests that extracellular vesicles are involved in the pathogenesis of HAND as they are believed to be transferring HIV-1 proteins to nearby neuronal cells. Although most studies assume homogeneity among populations, characterizing cellular proteins or RNA levels in bulk, we hypothesize that distinct populations of extracellular vesicles are released and that environmental conditions, including viral infections, …

Dexamethasone Treatment Effects On H3k27me3 Chromatin Organization Is Related To Nk Cell Immune Dysregulation, Michael Sarafeno Misale

Master's Theses

It is well-established that psychological stress reduces natural killer (NK) cell immune function. This reduction is mediated by stress-induced release of glucocorticoids (GC), which can suppress immune function. Associated with suppression of a particular immune function are GC induced histone-epigenetic marks. Histone-epigenetic marks are responsible for the organization and compartmentalization of genomes into transcriptionally active euchromatin domains that are localized to the interior of the nucleus. Transcriptionally silent heterochromatic domains are enriched with methylated epigenetic marks and are localized to the nuclear periphery. The purpose of this investigation was to assess the influence of GC on H3K27me3 chromatin organization by …

Multifunctional Regulatory T Cells From Human Umbilical Cord Blood And The Role Of Tumor Necrosis Factor In Immune Homeostasis, Alexander Nelson

Master's Theses

Regulatory T cells (Tregs) are required to suppress inflammation and prevent autoimmunity. During fetal development Tregs are crucial to maintain tolerance between mother and child. After birth, neonates require tolerance to avoid harmful immune responses to foreign antigens in food and allow colonization with commensal microbes. We demonstrate a propensity for T cells in human umbilical cord blood to differentiate into Tregs in response to antigen receptor stimulation ex vivo. Cord blood-derived Tregs potently suppress T cell proliferation, but also produce pro-inflammatory cytokines known to activate innate immune responses. These results suggest that antigen exposure during early life results in …

Role Of The Interleukin-22 And Stat3 Signaling Pathway In Gut Barrier Maintenance Following Intoxication And Burn Injury, Adam M. Hammer

Dissertations

More than half of patients admitted to burn centers for treatment have measurable alcohol levels in their blood. Intoxication that precedes a traumatic burn injury leads to worsened patient outcomes, including higher rates of infection and sepsis. The intestines harbor the largest concentration of bacteria in the human host. Any disruption of the intestinal barrier as a result of intoxication and burn injury could contribute to infection and/or sepsis from gut-derived microbes. Previous work has demonstrated that the intestinal barrier becomes leaky, and that administration of interleukin-22 (IL-22) significantly reduces gut barrier leakiness following alcohol and burn injury. However, the …

Monocyte-Induced Regulatory T Cell Differentiation, Jessica Genevieve Lee

Dissertations

Immediately after birth, thousands of foreign antigens challenge the newborn immune system. Many of the invaders are harmless, such as food, pollen, and beneficial bacteria. Newborns have a tolerant immune system that keeps them from developing inflammation or allergies to these new antigens. In utero, this immunoregulatory tendency is important for establishing tolerance to self and maternal antigens. Multiple processes contribute to fetal tolerance, including clonal deletion, anergy, changes in antigen presenting cells (APCs), and the generation of regulatory T cells (Tregs). However, the mechanism(s) of fetal Treg differentiation and the specific APCs required are unknown.

Our lab has previously …

Mechanism By Which Commensal Bacteria Limit Inflammation, Mallory Paynich

Dissertations

Trillions of bacteria live within the gastrointestinal tract and are critical for maintaining intestinal homeostasis; however, the mechanisms utilized by specific bacterial molecules to contribute to homeostasis are not well understood. We utilize a mouse model in which a single oral dose of the probiotic, Bacillus subtilis, protects mice from acute colitis induced by the enteric pathogen Citrobacter rodentium. Our goal is to elucidate the mechanism by which B. subtilis prevents inflammation.

We identified exopolysaccharides (EPS) to be the active molecule of B. subtilis, and a single dose of EPS protects mice from disease. EPS binds F4/80+CD11b+ peritoneal macrophages, and …

A Study Of Immune-Regulation Of Microbiota Supernatant On Macrophage Function, An N. Nguyen

Master's Theses

The diverse human microbial ecosystem colonizes many different body sites. The gastrointestinal (GI) tract, especially, is a major region that that harbors a complex microbial community composed of trillions of commensal bacteria. Interactions between the commensal bacteria and the host immune system begin at birth and continue through the human lifespan. In the gut, commensal bacteria help the host to ensure the maintenance of intestinal homeostasis as well as the mucosal barrier structure through host stimulation of mucus and antimicrobial molecules. The secretion of these host factors functions to inhibit pathogenic invasion and maintain the population of commensal bacteria. The …

Characterization Of Il-22-Producing Cells In The Human Thymus And The Mechanism By Which Il-22 Expression Is Modulated By Thymic Epithelial Cells., Nadine N. Morgan

Master's Theses

Thymic epithelial cells (TECs) are indispensable for T cell development and maturation. Therefore, damages to the thymic epithelial cells are detrimental to thymic function and immune response. In young healthy individuals, TECs have a high regenerative potential and are capable of renewal from serious damage; however, the molecular mechanism of this recovery is unclear. A recent study has shown that IL-22-producing ILCs are present in the mouse thymus and can regenerate thymic epithelial cells following radiation induced injuries. However, it is unknown whether IL-22-producing cells are also found in the human thymus. Thus, the goal of this study is to …

Defining The Role Of A Putative Peptidase In Staphylococcus Aureus Quorum Sensing And Pathogenesis, Chelsea Rose White

Master's Theses

The pathogenic bacterium Staphylococcus aureus encounters a variety of immune cells that restrict bacterial growth and dissemination during infection. However, S. aureus counters these immune cell functions by producing myriad virulence factors that facilitate evasion of host defenses. Therefore, it is important to understand S. aureus-immune cell interactions and the virulence factors that perturb normal immune function to promote pathogenesis. In a genetic screen designed to identify S. aureus secreted factors that modulate macrophage activity our lab identified a transposon insertion mutant in the gene SAUSA300_1984, encoding a putative membrane spanning peptidase. To investigate the role of 1984 in pathogenesis, …

Inhibition Of B Lymphopoiesis By Adipocytes And Myeloid-Derived Suppressor Cells, Domenick Kennedy

Dissertations

B lymphopoiesis declines with age in humans, mice, and rabbits. Impaired B lymphopoiesis correlates with increased fat in the bone marrow (BM), suggesting that adipocytes negatively regulate this process. In fact, adipocyte factors were found to inhibit B cell development in BM cultures.

Our goal was to understand the mechanism by which adipocytes inhibit B cell development. Through culturing mouse BM cells on OP9 stromal cells in the presence of adipocyte-conditioned medium (ACM), we found that adipocytes promote the accumulation of CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs). These cells were not simply bystanders, as we report for the first time that …

Characterization Of Exopolysaccharide (Eps) Produced By Bacillus Subtilis Mutants, Alexander Argianas

Master's Theses

Bacillus subtilis is a probiotic bacterium that can protect against the murine-

specific attaching and effacing (A/E) pathogen Citrobacter rodentium. C. rodentium displays many features observed with the human pathogen enteropathogenic E. coli (EPEC). Protection by B. subtilis is mediated by exopolysaccharide (EPS), which is encoded by the epsA-O operon that contains 15 genes. Disruption of one of these genes, epsH, which appears to encode a putative glycosyltransferase, leads to the loss of protective capacity by B. subtilis and by EPS. EPS is a major component of the B. subtilis biofilm and the ΔepsH mutant is unable to form a …

Role Of Heat Shock Proteins In Maintenance Of The Gut Barrier Following Burn Injury, Abigail Rhea Cannon

Master's Theses

Introduction: Burn injury remains a prominent clinical problem. Patients suffering from burns often succumb to secondary infectious complications leading to sepsis and widespread tissue injury ending in Multiple Organ Dysfunction. However, the mechanism behind the onset of these extraneous symptoms following burn injury is not fully understood. The integrity of the gut barrier is of critical importance as it harbors the largest bacterial reservoir in the body. Following burn injury, we observed a breakdown of the gut barrier resulting in increased gut leakiness and bacterial translocation. Under homeostatic conditions, heat shock proteins (HSPs) stabilize tight junction proteins. Particularly, HSP72 is …

Tcr Modifications To Enhance Expression, Chain Pairing, And Antigen Recognition For Adoptive T Cell Transfer, Kendra Foley

Master's Theses

T cell receptor (TCR) gene modified T cells for adoptive T cell transfer therapy have been shown to have clinical success in treating melanoma and other malignancies by redirecting the specificity of peripheral blood lymphocytes (PBL) to recognize tumor and/or viral associated antigens of choice. One of the challenges in using TCR gene modified T cells is the potential mispairing between endogenous and introduced alpha and beta TCR chains, allowing for unwanted off-target reactivity, autoimmunity, or impaired therapeutic efficacy. One approach to augment proper TCR chain pairing and to enhance T cell function involves the modification of the introduced TCR …

Role Of The Intestinal Microbiota In Gut Barrier Dysfunction Following Burn Injury, Zachary Earley

Master's Theses

Burn injury represents a major medical problem with half a million cases requiring medical attention and 4,000 deaths reported annually. Sepsis and multiple organ failure remain the leading causes of death following injury, and may be brought on by bacterial infections or toxins. The gastrointestinal tract contains approx. 100 trillion microbes; therefore, the indigenous commensal microbiota may play a role in leading to these complications or infections in burn patients. The overall objective of this project is to identify a potential mechanism whereby changes in gut bacteria may lead to intestinal inflammation or bacterial translocation--key factors which may lead to …

Characterizing The Mechanisms By Which Community Associated Methicillin-Resistant Staphylococcus Aureus Influences Keratinocyte Innate Immune Responses During Recurrent Infection, Ashley Lynn Larm

Master's Theses

Community associated–methicillin resistant Staphylococcus aureus (CA–MRSA) infection has become a major health concern. In human epidermal keratinocytes, S. aureus is mainly recognized through toll–like receptor 2 (TLR2) and its co–receptor, CD14. We hypothesize that CA–MRSA isolates cause recurrent infections by interrupting TLR2–mediated inflammation in keratinocytes. Recurrent CA–MRSA bacterial culture supernatant exposure to keratinocytes in vitro resulted in significant decreases in pro and anti–inflammatory cytokine and HMGB1 secretion from keratinocytes as assessed by ELISAs. Recurrent CA–MRSA live infection did not result in significant changes in cytokine or HMGB1 secretion, surface receptor expression, or NFκB activation post infection as assessed by ELISA …

Identification And Analysis Of Omentum Derived Suppressor Cells In Regards To Th17 Inhibition, Nick Huang

Dissertations

Omentum has been harnessed by surgeons for hundreds of years, providing an ideal environment for graft healing and acceptance. However, little is known about the cellular mechanisms that promote the tolergenic environment of the omentum. We examined the cellular composition and role of activated omentum in regards to T-cell immunomodulation. We then tested activated omentum as a cellular therapy in a mouse allogenic lung transplantation model.

Our findings demonstrated activated omentum is mostly comprised of non-hematopoietic cells resembling mesenchymal stem-like cells (MSCs) and myeloid derived suppressor cells (MDSCs). Activated omentum exhibited anti-inflammatory properties through suppression of Th1 and Th17, while …

The Effect Of Vitamin D On Human T Regulatory Cell Differentiation, Stephanie Anne Chapman

Master's Theses

Regulatory T cells (Tregs) are required for the induction and maintenance of immune homeostasis. Singh et al. demonstrated that depletion of Tregs in mice results in a loss of self-tolerance that manifests in the development of autoimmune diseases such as Inflammatory Bowel Disease (IBD). In humans, autoimmune diseases such as IBD, Multiple Sclerosis (MS), and Type 1 Diabetes are thought to occur due to a deficiency in the number or function of Tregs. The importance of Tregs in modulating the human immune system is perhaps best exemplified by IPEX (immune dysregulation, polyendocrinopathy, enteropathy, x-linked syndrome), a severe autoimmune disease characterized …

Particulates Initiate Immune Response Via Inducing Oxidative Stress-Mediated Nlrp3 Inflammasome Activation, Zhenyu Zhong

Dissertations

Liposomes are lipid particles formed by self-aggregated phospholipids. They are clinically used both as delivery vectors and immune adjuvants to treat many human infectious and cancerous diseases. However, how liposomes interact with host immune system remains poorly understood. Particularly, little is known about whether an innate immune receptor exists to sense liposomes. I hypothesize that liposomes activate NLRP3 inflammasome in macrophages, which results in the release of interleukin 1β (IL-1β), a proinflammatory cytokine that plays a key role in innate and adaptive immune responses.

To test my hypothesis, I determined the ability of inducing IL-1β secretion from macrophages by differentially …

Psychosocial Distress Mediates Immune Dysregulation Through Alterations In Global Epigenetic Patterns And Chromatin Remodeling Proteins, Karen Krukowski

Dissertations

Psychosocial distress, characterized by increased perceived stress, anxiety and mood disturbance, is a common response of women to a diagnosis of breast cancer (Northouse, 1992; Pettingale et al., 1988; Stark and House, 2000; Witek-Janusek et al., 2007). This psychosocial distress leads to activation of the hypothalamic-pituitary-adrenocortical (HPA) axis and increased circulating glucocorticoids (GCs) (Chrousos, 2000; Chrousos and Gold, 1992; Schoneveld and Cidlowski, 2007). Increased psychosocial distress and increased HPA activation can lead to immune dysregulation consisting of reduced natural killer (NK) cell activity (NKCA) (Biondi, 2001; Kiecolt-Glaser et al., 1987; Kiecolt-Glaser et al., 2002; Witek-Janusek et al., 2008; Witek-Janusek et …

Characterization Of Chronic Glucocorticoid Exposure On Natural Killer Cell Function: A Model For Stress Induced Alterations On The Epigenetic Landscape, Justin Lee Eddy

Dissertations

Psychological stress can impact immune function through altered glucocorticoid production. Natural killer (NK) cells and their effector functions are particularly susceptible to both psychological stress as well as exogenous glucocorticoids. The purpose of this study was to assess the impact of chronic glucocorticoid (GC) exposure on NK cells to investigate the immune dysregulation associated with periods of psychological stress.

Chronic in vitro treatment of the NK92 cell line produced a dichotomous NK phenotype with enhanced proinflammatory cytokine production yet reduced NK cell lytic activity (NKCA). This dichotomy was at the individual cell level where mRNA and protein levels for proinflammatory …

Ex Vivo Induction Of Human Regulatory T Cells, Kathleen Elizabeth Jaeger

Dissertations

Regulatory T cells (Tregs) are indispensable in the human immune system in the maintenance of self-tolerance and immune homeostasis. The dysregulation of Treg number and/or function plays a critical role in the pathogenesis of cancer, allergy and human autoimmune pathologies such as multiple sclerosis, psoriasis, rheumatoid arthritis and diabetes. The primary aim of this research was to determine the molecular mechanisms and cellular interactions which promote human Treg induction. From umbilical cord blood (UCB) samples, we found that antigen receptor stimulation of UCB T cells via a CD14+ monocyte population leads to a predominant induction of Tregs.

Further studies identified …

Defining A Role For Inducible Heat Shock Protein 70 (Hsp70i) In Mediating Autoimmune Vitiligo, Jeffrey Alan Mosenson

Dissertations

Vitiligo is an autoimmune disease characterized by destruction of melanocytes, leaving 0.5% of the population with progressive depigmentation. Current treatments offer limited efficacy. Observations that heat shock proteins (HSPs) can serve as adjuvants in antitumor vaccines first suggested to us a link between HSPs and stress-induced vitiligo. Such proteins are marvelously well conserved throughout evolution, which has placed them in the spotlight for helping to understand the intriguing relationship between infection and immunity. Intracellularly, inducible heat shock protein 70 (HSP70i) is upregulated by stress and helps protect cells from undergoing apoptosis. In times of stress, melanocytes will secrete antigen bound …

Evidence For Renewal And Reconstitution Of Marginal Zone Macrophages In Young And Aged Mice, Erika Bahamon

Master's Theses

Aging in humans and mice correlates with decline in immune health, affecting both innate and adaptive immunity. Response against blood-borne bacterial pathogens is compromised because of the deterioration of the marginal zones of the spleen and decrease in frequency of marginal zone macrophages (MZM). This thesis asked if low cell turnover is the cause for the decrease of MZM, using cell proliferation to indicate cell turnover in spleens of mice. First, evidence showed MZM proliferation occurred in spleens of young mice and was decreased in the MZM from aged mice. Second, transfer of young bone marrow into old mice replenished …

Characterization Of Inducible Regulatory T Cells: An Umbilical Cord Blood Model, Rebecca Anne Krier

Master's Theses

The immune system is a group of structures and processes that protect us from disease. To function properly it must recognize a wide variety of pathogens such as viruses and bacteria. T cells play a crucial role in an immune response; however, an overactive immune response can lead to autoimmune diseases, therefore it is important that the immune system has the ability to negatively regulate an immune response. In the periphery, regulatory T cells (CD4⁺CD25⁺Foxp3⁺) are involved in the maintenance of self-tolerance and immune homeostasis. Mechanisms involved in the induction of iTregs from naïve …

Selective Expansion Of B Cells By Intestinal Microbiota, Karina Ochoa

Master's Theses

In rabbits, antibody diversity and B cell expansion are generated in gut-associated lymphoid tissues (GALT), in an antigen- and T cell-independent mechanism, and require interaction with intestinal microbiota. I investigated, in vitro, the mechanism by which commensals drive GALT reactions. Bacteria were isolated from the GALT of rabbits and identified by 16sRNA sequencing. I found that the commensals can bind to Ig, independently of their specificity. In addition, a ~20kDa bacterial molecule was immunoprecipitated with recombinant Ig molecules. Stimulation of B cells with selected bacterial molecules induced the activation of B cells. Stimulation of B cells through TLR2 induced the …

Cell Biology Of Foxp3+ Regulatory T Cells, Mariko Takami

Dissertations

T cells play a central role in the immune response to fight against pathogens and orchestrate other immune cells. An overreactive immune response can lead to autoimmune diseases, therefore the immune system must possess negative regulation mechanisms. In the periphery, naturally arising regulatory T cells (nTregs) negatively regulate immune responses and play an important role in maintaining immune homeostasis. When antigens are present, conventional CD4+ T cells recognize their cognate antigen and proliferate. After pathogen clearance, expanded effector T cells eventually decline in number due to activation induced cell death (AICD) to terminate immune response. However, it is not understood …

Urinary Antimicrobial Peptides And The Urinary Microbiota In A Uti-Susceptible Population Of Female Pelvic Floor Surgery Patients, Vanessa Nienhouse

Master's Theses

Urinary tract infections (UTI)s are a national priority. Women who undergo surgery for pelvic floor disorders such as pelvic organ prolapse (POP) or urinary incontinence (UI) are at increased risk for UTI, as 10-30% will contract a post-instrumentation UTI (postI-UTI) within six weeks after surgery. Currently, the factors that contribute to the high rate of postI-UTI are unknown, and there is currently no clinical assessment to identify at-risk patients. However, antimicrobial peptides (AMPs) and characteristics of the urinary microbiota have the potential to serve as biomarkers, identifying patients at UTI risk and facilitating clinical prevention studies.

While it was previously …

Binge Ethanol Leads To Decreased Macrophage Accumulation In Infected Cutaneous Wounds, Sara Hlavin

Master's Theses

Trauma patients who consumed alcohol prior to sustaining injuries have higher rates of morbidity and mortality than those with comparable injuries who did not drink. Additionally, those who drank had impaired wound healing and increased susceptibility to infection. Despite these clinical observations, few studies have explored the effect of ethanol on the innate immune cell function in a healing wound or how this may alter resolution of cutaneous infection. A murine model of ethanol and cutaneous wound infection was used to examine bacterial growth and recruitment of innate immune cells. Mice were given either ethanol (2.2 g/kg) or saline 30 …