Medical Immunology Commons^™

Differential Spatial Repositioning Of Activated Genes In Biomphalaria Glabrata Snails Infected With Schistosoma Mansoni, Halime D. Arican-Goktas, Wannaporn Ittiprasert, Joanna M. Bridger, Matty Knight

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bacteria, for example, can induce beneficial chromatin remodelling of the host genome. We have previously shown in vitro thatBiomphalaria glabrata embryonic cells co-cultured with schistosome miracidia display genes changing their …

Diminished Humoral Responses Against And Reduced Gene Expression Levels Of Human Endogenous Retrovirus-K (Herv-K) In Psoriasis, Rashmi Gupta, Henri-Alexandre Michaud, Xue Zeng, Maya Debbaneh, Sarah T. Arron, R. Brad Jones, Christopher E. Ormsby, Douglas F. Nixon, Wilson Liao

Microbiology, Immunology, and Tropical Medicine Faculty Publications

No abstract provided.

Vaccination With A Genetically Modified Brugia Malayi Cysteine Protease Inhibitor-2 Reduces Adult Parasite Numbers And Affects The Fertility Of Female Worms Following A Subcutaneous Challenge Of Mongolian Gerbils (Meriones Unguiculatus) With B. Malayi Infective Larvae., Sridhar Arumugam, Junfei Wei, Danielle Ward, David Abraham, Sara Lustigman, Bin Zhan, Thomas R. Klei

Department of Microbiology and Immunology Faculty Papers

Vaccination of Mongolian gerbils with Brugia malayi cysteine protease inhibitor-2 in which the amino acid Asn66 was mutated to Lys66 (Bm-CPI-2M) resulted in reduced parasite numbers of 48.6% and 48.0% at 42 and 90 days p.i. with B. malayi L3s. Fertility of female worms was also affected at 90 days p.i. In vitro killing of L3s observed in the presence of gerbil peritoneal exudate cells and anti-Bm-CPI-2M sera suggests antibody-dependent cell-mediated cytotoxicity as a putative protective mechanism. These observations suggest that Bm-CPI-2M is a promising prophylactic and anti-fecundity vaccine candidate.

Cyclic Di-Gmp-Dependent Signaling Pathways In The Pathogenic Firmicute Listeria Monocytogenes, Li-Hong Chen, Volkan K. Köseoğlu, Zehra T. Güvener, Tanya Myers-Morales, Joseph M. Reed, Sarah E. F. D'Orazio, Kurt W. Miller, Mark Gomelsky

Microbiology, Immunology, and Molecular Genetics Faculty Publications

We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all phosphodiesterase …

Cyclic Di-Gmp-Dependent Signaling Pathways In The Pathogenic Firmicute Listeria Monocytogenes, Li-Hong Chen, Volkan K. Köseoğlu, Zehra T. Güvener, Tanya Myers-Morales, Joseph M. Reed, Sarah E. F. D'Orazio, Kurt W. Miller, Mark Gomelsky

Microbiology, Immunology, and Molecular Genetics Faculty Publications

We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all …

Vaccines To Combat River Blindness: Expression, Selection And Formulation Of Vaccines Against Infection With Onchocerca Volvulus In A Mouse Model., Jessica A. Hess, Bin Zhan, Sandra Bonne-Annee, Jessica M. Deckman, Maria Elena Bottazzi, Peter J. Hotez, Thomas R R. Klei, Sara Lustigman, David Abraham

Department of Microbiology and Immunology Faculty Papers

Human onchocerciasis is a neglected tropical disease caused by Onchocerca volvulus and an important cause of blindness and chronic disability in the developing world. Although mass drug administration of ivermectin has had a profound effect on control of the disease, additional tools are critically needed including the need for a vaccine against onchocerciasis. The objectives of the present study were to: (i) select antigens with known vaccine pedigrees as components of a vaccine; (ii) produce the selected vaccine antigens under controlled conditions, using two expression systems and in one laboratory and (iii) evaluate their vaccine efficacy using a single immunisation …

Vcam-1/Α4Β1 Integrin Interaction Is Crucial For Prompt Recruitment Of Immune T Cells Into The Brain During The Early Stage Of Reactivation Of Chronic Infection With Toxoplasma Gondii To Prevent Toxoplasmic Encephalitis, Qila Sa, Eri Ochiai, Tomoko Sengoku, Melinda E. Wilson, Morgan Brogli, Stephen Crutcher, Sara A. Michie, Baohui Xu, Laura Payne, Xisheng Wang, Yasuhiro Suzuki

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Reactivation of chronic infection with Toxoplasma gondii can cause life-threatening toxoplasmic encephalitis in immunocompromised individuals. We examined the role of VCAM-1/α4β1 integrin interaction in T cell recruitment to prevent reactivation of the infection in the brain. SCID mice were infected and treated with sulfadiazine to establish a chronic infection. VCAM-1 and ICAM-1 were the endothelial adhesion molecules detected on cerebral vessels of the infected SCID and wild-type animals. Immune T cells from infected wild-type mice were treated with anti-α4 integrin or control antibodies and transferred into infected SCID or nude mice, and the animals received the same antibody every other …

Systemic Hematogenous Maintenance Of Memory Inflation By Mcmv Infection., Corinne J Smith, Holly Turula, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

Several low-grade persistent viral infections induce and sustain very large numbers of virus-specific effector T cells. This was first described as a response to cytomegalovirus (CMV), a herpesvirus that establishes a life-long persistent/latent infection, and sustains the largest known effector T cell populations in healthy people. These T cells remain functional and traffic systemically, which has led to the recent exploration of CMV as a persistent vaccine vector. However, the maintenance of this remarkable response is not understood. Current models propose that reservoirs of viral antigen and/or latently infected cells in lymph nodes stimulate T cell proliferation and effector differentiation, …

Fty720 (Fingolimod) Provides Insight Into The Molecular Mechanisms Of Multiple Sclerosis, Madelyn Elizabeth Crawford

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Multiple sclerosis (MS) is a neurodegenerative disorder caused by a prolonged immune- mediated inflammatory response that targets myelin. Nearly all of the drugs approved for the treatment of MS are general immunosuppressants or only function in symptom management. The oral medication fingolimod, however, is reported to have direct therapeutic effects on cells of the central nervous system in addition to immunomodulatory functions. Fingolimod is known to interact with sphingosine-1-phosphate (S1P) receptors, and the most widely- accepted theory for its mechanism of action is functional antagonism of the receptor. This review examines significant neuromodulatory effects achieved by functional antagonism of the …

Immunomodulatory Activity Of Interferon-Beta, Lloyd H. Kasper, Anthony T. Reder

Dartmouth Scholarship

Multiple sclerosis (MS) is a complex disorder of the central nervous system that appears to be driven by a shift in immune functioning toward excess inflammation that results in demyelination and axonal loss. Beta interferons were the first class of disease-modifying therapies to be approved for patients with MS after treatment with this type I interferon improved the course of MS on both clinical and radiological measures in clinical trials. The mechanism of action of interferon-beta appears to be driven by influencing the immune system at many levels, including antigen-presenting cells, T cells, and B cells. One effect of these …

Intrinsic Innate Immunity Fails To Control Herpes Simplex Virus And Vesicular Stomatitis Virus Replication In Sensory Neurons And Fibroblasts, Pamela C. Rosato, David A. Leib

Dartmouth Scholarship

Herpes simplex virus 1 (HSV-1) establishes lifelong latent infections in the sensory neurons of the trigeminal ganglia (TG), wherein it retains the capacity to reactivate. The interferon (IFN)-driven antiviral response is critical for the control of HSV-1 acute replication. We therefore sought to further investigate this response in TG neurons cultured from adult mice deficient in a variety of IFN signaling components. Parallel experiments were also performed in fibroblasts isolated concurrently. We showed that HSV-1 replication was comparable in wild-type (WT) and IFN signaling-deficient neurons and fibroblasts. Unexpectedly, a similar pattern was observed for the IFN-sensitive vesicular stomatitis virus (VSV). …

New Clues To Understanding Hiv Nonprogressors: Low Cholesterol Blocks Hiv Trans Infection, Vinayaka R. Prasad, Michael I. Bukrinsky

Microbiology, Immunology, and Tropical Medicine Faculty Publications

A small percentage of HIV-infected subjects (2 to 15%) are able to control disease progression for many years without antiretroviral therapy. Years of intense studies of virologic and immunologic mechanisms of disease control in such individuals yielded a number of possible host genes that could be responsible for the preservation of immune functions, from immune surveillance genes, chemokines, or their receptors to anti-HIV restriction factors. A recent mBiopaper by Rappocciolo et al. (G. Rappocciolo, M. Jais, P. Piazza, T. A. Reinhart, S. J. Berendam, L. Garcia-Exposito, P. Gupta, and C. R. Rinaldo, mBio 5:e01031-13, 2014) describes another potential factor …

Genome-Wide Analysis Of Regulatory Proteases Sequences Identified Through Bioinformatics Data Mining In Taenia Solium, Hong-Bin Yan, Zhong-Zi Lou, Li Li, Paul J. Brindley, Yadong Zheng, Xuenong Luo, Junling Hou, Aijiang Guo, Wan-Zhong Jia, Xuepeng Cai

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Background

Cysticercosis remains a major neglected tropical disease of humanity in many regions, especially in sub-Saharan Africa, Central America and elsewhere. Owing to the emerging drug resistance and the inability of current drugs to prevent re-infection, identification of novel vaccines and chemotherapeutic agents against Taenia solium and related helminth pathogens is a public health priority. The T. solium genome and the predicted proteome were reported recently, providing a wealth of information from which new interventional targets might be identified. In order to characterize and classify the entire repertoire of protease-encoding genes of T. solium, which act fundamental biological roles in …

Secretory Iga Is Concentrated In The Outer Layer Of Colonic Mucus Along With Gut Bacteria, Eric W. Rogier, Aubrey L. Frantz, Maria E. C. Bruno, Charlotte S. Kaetzel

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Antibodies of the secretory IgA (SIgA) class comprise the first line of antigen-specific immune defense, preventing access of commensal and pathogenic microorganisms and their secreted products into the body proper. In addition to preventing infection, SIgA shapes the composition of the gut microbiome. SIgA is transported across intestinal epithelial cells into gut secretions by the polymeric immunoglobulin receptor (pIgR). The epithelial surface is protected by a thick network of mucus, which is composed of a dense, sterile inner layer and a loose outer layer that is colonized by commensal bacteria. Immunofluorescence microscopy of mouse and human colon tissues demonstrated that …

Extracellular Traps Are Associated With Human And Mouse Neutrophil And Macrophage Mediated Killing Of Larval Strongyloides Stercoralis., Sandra Bonne-Annee, Laura A. Kerepesi, Jessica A. Hess, Jordan Wesolowski, Fabienne Paumet, James B. Lok, Thomas J. Nolan, David Abraham

Department of Microbiology and Immunology Faculty Papers

Neutrophils are multifaceted cells that are often the immune system's first line of defense. Human and murine cells release extracellular DNA traps (ETs) in response to several pathogens and diseases. Neutrophil extracellular trap (NET) formation is crucial to trapping and killing extracellular pathogens. Aside from neutrophils, macrophages and eosinophils also release ETs. We hypothesized that ETs serve as a mechanism of ensnaring the large and highly motile helminth parasite Strongyloides stercoralis thereby providing a static target for the immune response. We demonstrated that S. stercoralis larvae trigger the release of ETs by human neutrophils and macrophages. Analysis of NETs revealed …

Urinary Estrogen Metabolites And Self-Reported Infertility In Women Infected With Schistosoma Haematobium, Julio Santos, Maria Joao Gouveia, Nuno Vale, Maria De Lurdes Delgado, Ana Goncalves, Gabriel Rinaldi, Paul J. Brindley, +10 Additional Authors

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Background

Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsive cells. In addition, schistosome derived catechol-estrogens induce genotoxicity that result in estrogen-DNA adducts. These catechol estrogens and the catechol-estrogen-DNA adducts can be isolated from sera of people infected with S. haematobium. The aim of this study was to study infertility in females infected with S. haematobium and its …

The Use Of Nanotrap Particles Technology In Capturing Hiv-1 Virions And Viral Proteins From Infected Cells, Elizabeth Jaworski, Mohammed Saifuddin, Gavin C. Sampey, Nazly Shafagati, Rachel Van Duyne, Sergey N. Iordanskiy, Kylene Kehn-Hall, Lance Liotta, Emanuel F. Petricoin Iii, Mary Young, Benjamin Lepene

Microbiology, Immunology, and Tropical Medicine Faculty Publications

HIV-1 infection results in a chronic but incurable illness since long-term HAART can keep the virus to an undetectable level. However, discontinuation of therapy rapidly increases viral burden. Moreover, patients under HAART frequently develop various metabolic disorders and HIV-associated neuronal disease. Today, the main challenge of HIV-1 research is the elimination of the residual virus in infected individuals. The current HIV-1 diagnostics are largely comprised of serological and nucleic acid based technologies. Our goal is to integrate the nanotrap technology into a standard research tool that will allow sensitive detection of HIV-1 infection. This study demonstrates that majority of HIV-1 …

Cd27high/Klrg1low Cd8+ T Cells That Persist Throughout Mcmv Infection Are Highly Expansive And Have The Ability To Reestablish Mcmv Immunity, Michael Quinn, Holly Turula, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

Abstract

Cytomegalovirus (CMV) is a herpesvirus that establishes life-long latency in 60-80% of Americans. Constant immune surveillance is necessary to prevent viral reactivation from latency and results in the accumulation of functional CMV-specific CD8+ T cells (CD8s) over time, a process termed memory inflation. As such, CMV reactivations remain a clinical concern for immunosuppressed patients and reconstituting CMV immunity is critical for the long-term prevention of CMV disease. Understanding the maintenance of memory inflation may reveal novel approaches to restore CMV immunity.

Previous work has shown that the majority of inflationary CD8s express a terminally-differentiated “effector” (T_EFF) phenotype, …

Suppression Of Basophil Histamine-Release And Other Ige-Dependent Responses In Childhood Schistosoma Mansoni Hookworm Co-Infection, Angela Pinot De Moira, Colin M. Fitzsimmons, Frances M. Jones, Shona Wilson, Pierre Cahen, Edridah Tukahebwa, Harriet Mpairwe, Joseph K. Mwatha, Jeffrey M. Bethony, Per S. Skov, Narcis B. Kabatereine, David W. Dunne

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Background. The poor correlation between allergen-specific-IgE (asIgE) and clinical signs of allergy in helminth infected populations suggests that helminth infections could protect against allergy by uncoupling asIgE from its effector mechanisms. We investigated this hypothesis in Ugandan schoolchildren coinfected with Schistosoma mansoni and hookworm.

Methods. Skin prick test (SPT) sensitivity to house dust mite allergen (HDM) and current wheeze were assessed pre-anthelmintic treatment. Non-specific (anti-IgE), helminth-specific and HDM-allergen-specific basophil histamine release (HR), plus helminth- and HDM-specific IgE and IgG4 responses were measured pre- and post-treatment.

Results. Non-specific- and helminth-specific-HR, and associations between helminth-specific-IgE and helminth-specific-HR increased post-treatment. Hookworm infection appeared …

Avirulent Strains Of Toxoplasma Gondii Infect Macrophages By Active Invasion From The Phagosome, Yanlin Zhao, Andrew H. Marple, David J. P. Ferguson, David J. Bzik, George S. Yap

Dartmouth Scholarship

Unlike most intracellular pathogens that gain access into host cells through endocytic pathways, Toxoplasma gondii initiates infection at the cell surface by active penetration through a moving junction and subsequent formation of a parasitophorous vacuole. Here, we describe a noncanonical pathway for T. gondii infection of macrophages, in which parasites are initially internalized through phagocytosis, and then actively invade from within a phagosomal compartment to form a parasitophorous vacuole. This phagosome to vacuole invasion (PTVI) pathway may represent an intermediary link between the endocytic and the penetrative routes for host cell entry by intracellular pathogens. The PTVI pathway is preferentially …

Limited Brain Metabolism Changes Differentiate Between The Progression And Clearance Of Rabies Virus., Keith Schutsky, Carla Portocarrero, D Craig Hooper, Bernhard Dietzschold, Milosz Faber

Department of Microbiology and Immunology Faculty Papers

Central nervous system (CNS) metabolic profiles were examined from rabies virus (RABV)-infected mice that were either mock-treated or received post-exposure treatment (PET) with a single dose of the live recombinant RABV vaccine TriGAS. CNS tissue harvested from mock-treated mice at middle and late stage infection revealed numerous changes in energy metabolites, neurotransmitters and stress hormones that correlated with replication levels of viral RNA. Although the large majority of these metabolic changes were completely absent in the brains of TriGAS-treated mice most likely due to the strong reduction in virus spread, TriGAS treatment resulted in the up-regulation of the expression of …

Interleukin-7-Dependent B Lymphocytes Are Required For The Anti-Pneumococcal Polysaccharide Response And Protective Immunity To Streptococcus Pneumoniae, Gregory S. Dickinson, Phd, Raja Vuyyuru, Timothy L. Manser, Phd, John F. Kerney, Kishore Alugupalli, Phd

Department of Microbiology and Immunology Faculty Papers

Unlike human adults or adult mice, young children or young mice respond poorly to pneumococcal polysaccharides (PPS). In mice, B1b lymphocytes are the major responders to a variety of bacterial polysaccharides including PPS. Despite having B1b cells, young mice are severely impaired in responding to PPS, suggesting that B cells in the young are distinct from those in adults. Since B lymphopoeisis early in life is largely Interleukin-7 (IL-7)-independent, while in adults it is IL-7-dependent, we hypothesize that B cells developed in the presence of IL-7 are required for generating anti-PPS antibody responses. In support of this, we found that …

An Immunomics Approach To Schistosome Antigen Discovery: Antibody Signatures Of Naturally Resistant And Chronically Infected Individuals From Endemic Areas, Soraya Gaze, Patrick Driguez, Mark S. Pearson, Tiago Mendes, Denise L. Doolan, Jeffrey M. Bethony, +14 Additional Authors

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Schistosomiasis is a neglected tropical disease that is responsible for almost 300,000 deaths annually. Mass drug administration (MDA) is used worldwide for the control of schistosomiasis, but chemotherapy fails to prevent reinfection with schistosomes, so MDA alone is not sufficient to eliminate the disease, and a prophylactic vaccine is required. Herein, we take advantage of recent advances in systems biology and longitudinal studies in schistosomiasis endemic areas in Brazil to pilot an immunomics approach to the discovery of schistosomiasis vaccine antigens. We selected mostly surface-derived proteins, produced them using an in vitro rapid translation system and then printed them to …

Autoantibodies To Agrin In Myasthenia Gravis Patients, Bin Zhang, Chengyong Shen, Beverly Bealmear, Samia Ragheb, Wen-Cheng Xiong, Richard A. Lewis, Robert P. Lisak, Lin Mei

Immunology and Microbiology Faculty Research Publications

To determine if patients with myasthenia gravis (MG) have antibodies to agrin, a proteoglycan released by motor neurons and is critical for neuromuscular junction (NMJ) formation, we collected serum samples from 93 patients with MG with known status of antibodies to acetylcholine receptor (AChR), muscle specific kinase (MuSK) and lipoprotein-related 4 (LRP4) and samples from control subjects (healthy individuals and individuals with other diseases). Sera were assayed for antibodies to agrin. We found antibodies to agrin in 7 serum samples of MG patients. None of the 25 healthy controls and none of the 55 control neurological patients had agrin antibodies. …

Genome Of The Human Hookworm Necator Americanus, Yat T. Tang, Xin Gao, Bruce A. Rosa, Sahar Abubucker, Kymberlie Hallsworth-Pepin, Peter J. Hotez, Jeffrey M. Bethony, +23 Additional Authors

Microbiology, Immunology, and Tropical Medicine Faculty Publications

The hookworm Necator americanus is the predominant soil-transmitted human parasite. Adult worms feed on blood in the small intestine, causing iron-deficiency anemia, malnutrition, growth and development stunting in children, and severe morbidity and mortality during pregnancy in women. We report sequencing and assembly of the N. americanus genome (244 Mb, 19,151 genes). Characterization of this first hookworm genome sequence identified genes orchestrating the hookworm's invasion of the human host, genes involved in blood feeding and development, and genes encoding proteins that represent new potential drug targets against hookworms. N. americanus has undergone a considerable and unique expansion of immunomodulator proteins, …

Myd88-Dependent Immunity To A Natural Model Of Vaccinia Virus Infection Does Not Involve Toll-Like Receptor 2., Michael L Davies, Janet J Sei, Nicholas A Siciliano, Ren-Huan Xu, Felicia Roscoe, Luis J Sigal, Laurence C. Eisenlohr, Christopher C Norbury

Department of Microbiology and Immunology Faculty Papers

UNLABELLED: Although the pattern recognition receptor Toll-like receptor 2 (TLR2) is typically thought to recognize bacterial components, it has been described to alter the induction of both innate and adaptive immunity to a number of viruses, including vaccinia virus (VACV). However, many pathogens that reportedly encode TLR2 agonists may actually be artifactually contaminated during preparation, possibly with cellular debris or merely with molecules that sensitize cells to be activated by authentic TLR2 agonists. In both humans and mice, the most relevant natural route of infection with VACV is through intradermal infection of the skin. Therefore, we examined the requirement for …

Systematic Analysis Of A Xenograft Mice Model For Kshv+ Primary Effusion Lymphoma (Pel), Lu Dai, Jimena Trillo-Tinoco, Lihua Bai, Baoli Kang, Zengguang Xu, Xiaofei Wen, Luis Del Valle, Zhiqiang Qin

School of Medicine Faculty Publications

Kaposi's sarcoma-associated herpesvirus is the causative agent of primary effusion lymphoma (PEL), which arises preferentially in the setting of infection with human immunodeficiency virus (HIV). Even with standard cytotoxic chemotherapy, PEL continues to cause high mortality rates, requiring the development of novel therapeutic strategies. PEL xenograft models employing immunodeficient mice have been used to study the in vivo effects of a variety of therapeutic approaches. However, it remains unclear whether these xenograft models entirely reflect clinical presentations of KSHV(+) PEL, especially given the recent description of extracavitary solid tumor variants arising in patients. In addition, effusion and solid tumor cells …

B Cell Tolerance In Health And Disease, Murali Gururajan, Vishal J. Sindhava, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

B lymphocyte receptors are generated randomly during the bone marrow developmental phase of B cells. Hence, the B cell repertoire consists of both self and foreign antigen specificities necessitating specific tolerance mechanisms to eliminate self-reactive B cells. This review summarizes the major mechanisms of B cell tolerance, which include clonal deletion, anergy and receptor editing. In the bone marrow presentation of antigen in membrane bound form is more effective than soluble form and the role of dendritic cells in this process is discussed. Toll like receptor derived signals affect activation of B cells by certain ligands such as nucleic acids …

A Melanin-Independent Interaction Between Mc1r And Met Signalling Pathways Is Required For Hgf-Dependent Melanoma, Agnieszka Wolnicka-Głubisz, Faith M. Strickland, Albert Wielgus, Miriam Anver, Glenn Merlino, Edward C. De Fabo, Frances P. Noonan

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Melanocortin 1 receptor (MC1R) signaling stimulates black eumelanin production through a cAMP-dependent pathway. MC1R polymorphisms can impair this process, resulting in a predominance of red phaeomelanin. The red hair, fair skin and UV sensitive phenotype is a well-described melanoma risk factor. MC1R polymorphisms also confer melanoma risk independent of pigment. We investigated the effect of Mc1r deficiency in a mouse model of UV-induced melanoma. C57BL/6-Mc1r+/+-HGF transgenic mice have a characteristic hyperpigmented black phenotype with extra-follicular dermal melanocytes located at the dermal/epidermal junction. UVB induces melanoma, independent of melanin pigmentation, but UVA-induced and spontaneous melanomas are dependent on black eumelanin. We …

Prion Infection Impairs Cholesterol Metabolism In Neuronal Cells, Huanhuan L. Cui, Belinda Guo, Benjamin Scicluna, Bradley M. Coleman, Victoria A. Lawson, Laura Ellett, Peter J. Meikle, Michael I. Bukrinsky, Nigora Mukhamedova, Dmitri Sviridov, Andrew F. Hill

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Conversion of prion protein (PrP^C) into a pathological isoform (PrP^Sc) during prion infection occurs in lipid rafts and is dependent on cholesterol. Here, we show that prion infection increases the abundance of cholesterol transporter, ATP-binding cassette transporter type A1 (ATP-binding cassette transporter type A1), but reduces cholesterol efflux from neuronal cells leading to the accumulation of cellular cholesterol. Increased abundance of ABCA1 in prion disease was confirmed in prion-infected mice. Mechanistically, conversion of PrP^C to the pathological isoform led to PrP^Sc accumulation in rafts, displacement of ABCA1 from rafts and the cell surface, and …