Medical Immunology Commons^™

Identification Of Molecular Determinants From Moloney Leukemia Virus 10 Homolog (Mov10) Protein For Virion Packaging And Anti-Hiv-1 Activity, Aierken Abudu, Xiaojun Wang, Ying Dang, Tao Zhou, Shi-Hua Xiang, Yong -Hui Zheng

Nebraska Center for Virology: Faculty Publications

Background: MOV₁₀ inhibits HIV-1 replication after being packaged.

Results: A Gag binding plus all but one of seven helicase domains are required for MOV^₁₀ packaging. Nearly all residues are required for anti-HIV-1 activity. Conclusion: Gag binding is not sufficient for MOV₁₀ packaging, and multiple discontinuous domains regulate MOV₁₀ activity.

Significance: These findings uncover a new packaging mechanism and provide new insights into MOV₁₀ antiviral activity.

Contribution Of The Infection-Associated Complement Regulator-Acquiring Surface Protein 4 (Erpc) To Complement Resistance Of Borrelia Burgdorferi, Claudia Hammerschmidt, Teresia Hallström, Christine Skerka, Reinhard Wallich, Brian Stevenson, Peter F Zipfel, Peter Kraiczy

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Borrelia burgdorferi evades complement-mediated killing by interacting with complement regulators through distinct complement regulator-acquiring surface proteins (CRASPs). Here, we extend our analyses to the contribution of CRASP-4 in mediating complement resistance of B. burgdorferi and its interaction with human complement regulators. CRASP-4 (also known as ErpC) was immobilized onto magnetic beads and used to capture proteins from human serum. Following Western blotting, factor H (CFH), CFH-related protein 1 (CFHR1), CFHR2, and CFHR5 were identified as ligands of CRASP-4. To analyze the impact of native CRASP-4 on mediating survival of serum-sensitive cells in human serum, a B. garinii strain was generated …

Effects Of Apoptotic Cell Accumulation Caused By Mer Deficiency On Germinal Center B Cells And Helper T Cells, Tahsin N. Khan, Eric B. Wong, Ziaur S.M. Rahman

Department of Microbiology and Immunology Faculty Papers

Mer (MerTK), a member of the Tyro-3/Axl/Mer subfamily receptor tyrosine kinases, expression on phagocytes facilitates their clearance of apoptotic cells (ACs). Mer expression in germinal centers (GCs) occurs predominantly on tingible body macrophages. B and T cells do not express Mer. Mer deficiency (Mer-/-) results in the accumulation of ACs in GCs and augmented antibody-forming cell (AFC), GC and IgG2 Ab responses against T-dependent (TD) Ag. Here, we show that AC accumulation in GCs and elevated AFC, GC and IgG2 Ab responses in Mer-/- mice lasted for at least 80 days after immunization with NP-OVA. Enhanced responses and AC accumulation …

A Novel Function For Snap29 (Synaptosomal-Associated Protein Of 29 Kda) In Mast Cell Phagocytosis., Jordan Wesolowski, Vernon Caldwell, Fabienne Paumet

Department of Microbiology and Immunology Faculty Papers

Mast cells play a critical role in the innate immune response to bacterial infection. They internalize and kill a variety of bacteria and process antigen for presentation to T cells via MHC molecules. Although mast cell phagocytosis appears to play a significant role during bacterial infection, little is known about the proteins involved in its regulation. In this study, we demonstrate that the SNARE protein SNAP29 is involved in mast cell phagocytosis. SNAP29 is localized in the endocytic pathway and is transiently recruited to Escherichia coli (E. coli)-containing phagosomes. Interestingly, overexpression of SNAP29 significantly increases the internalization and killing of …

Dynamics Of Envelope Evolution In Clade C Shiv-Infected Pig-Tailed Macaques During Disease Progression Analyzed By Ultra-Deep Pyrosequencing, For Yue Tso, Damien C. Tully, Sandra Gonzalez, Christopher Quince, On Ho, Patricia Polacino, Ruth M. Ruprecht, Shiu-Lok Hu, Charles Wood

Nebraska Center for Virology: Faculty Publications

Understanding the evolution of the human immunodeficiency virus type 1 (HIV-1) envelope during disease progression can provide tremendous insights for vaccine development, and simian-human immunodeficiency virus (SHIV) infection of nonhuman primate provides an ideal platform for such studies. A newly developed clade C SHIV, SHIV-1157ipd3N4, which was able to infect rhesus macaques, closely resembled primary HIV-1 in transmission and pathogenesis, was used to infect several pig-tailed macaques. One of the infected animals subsequently progressed to AIDS, whereas one remained a nonprogressor. The viral envelope evolution in the infected animals during disease progression was analyzed by a bioinformatics approach using ultra-deep …

Mobilizing Subdominant Hiv-Specific Ctls As A Novel Vaccine Strategy, Margaret Christina Costanzo

Open Access Theses & Dissertations

To overcome the extreme antigenic diversity of HIV, there is increasing interest in developing vaccines that target CD8 T cell responses to conserved regions of the viral proteome. Understanding the immunogenic potential of these domains is therefore critical for the success of this vaccine strategy. CD8 T cell responses to conserved domains restricted by the "neutral" and highly prevalent HLA-A2 allele have not been extensively characterized. Here we describe a novel essentially invariant 10-mer epitope in HIV Gag (p2414-23, RTLNAWVKVV (RV10)) in that it is expressed by the majority HIV isolates from all clades. Here we examined the character of …

Evaluation Of Protection Induced By Dna Vaccine Candidate Against Leishmania Mexicana In Balb/C Mice Model, Rosina Rodarte

Open Access Theses & Dissertations

Background and Significance. The leishmaniases are a diverse group of diseases with four major clinical manifestations: cutaneous, mucocutaneous, visceral, and diffuse. Approximately 21 Leishmania species and 30 sandfly vectors have been implicated in human leishmaniasis. Leishmaniasis is endemic in 88 countries, 72 are developing countries. Currently, 350 million people live in leishmaniasis-endemic areas around the world. The true incidence of the disease is not known. However, the estimated incidence for visceral leishmaniasis is 500,000 cases per year, and for cutaneous and mucocutaneous leishmaniasis 1.5-2 million cases per year. Visceral leishmaniasis causes 70,000 deaths each year. In the Americas region, …

Role Of The Immune System And Bioactive Lipids In Trafficking Bone Marrow-Derived Stem Cells In Patients With Ischemic Heart Disease, Ahmed Abdel-Latif

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Acute myocardial infarction (AMI) triggers the mobilization of stem/progenitor cells from bone marrow (BMSPCs) into peripheral blood (PB). The underlying mechanisms orchestrating this mobilization and subsequent homing of BMSPCs to the myocardium are poorly understood. While the role of traditional chemokines in the mobilization and homing of hematopoietic stem cell (HSCs) to BM niches is undisputed, their role in directing BMSPCs to the highly proteolytic environment of the ischemic myocardium is debatable and other redundant mechanism may exist. Based on our observation that bioactive lipids, such as sphingosine-1 phosphate (S1P) and ceramide-1 phosphate (C1P), play an important role in regulating …

Regulation Of Hepatic Gene Expression During Liver Development And Disease, Hui Ren

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

My first project was to investigate the role of Hepatocyte Nuclear Factor 1 (HNF1) and Nuclear Factor I (NFI) on alpha-fetoprotein (AFP) promoter activity during liver development. AFP is highly expressed in the fetal liver, silenced at birth, and remains at very low levels in the adult liver. A GA substitution located at -119 of the human AFP promoter is associated with hereditary persistence of AFP (HPAFP) expression in the adult liver (Hum Molec Genet, 1993, 2:379). The -120 region harbors overlapping binding sites for HNF1 and NFI. While it has been shown that the GA substitution increases HNF1 binding, …

Signaling Mechanisms Involved In The Generation Of Human Peripheral Itregs, Mary Catherine Reneer

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Maintaining balance in the human immune system is critical for the body’s ability to discriminate between foreign and self-antigens. This balance is achieved, in part, by a subpopulation of T cells known as induced regulatory T cells (iTregs). Dysregulation of this population may contribute to the onset and progression of cancer, chronic inflammation and autoimmune diseases. Therefore, manipulation of iTreg development holds promising therapeutic potential; however, studying this vital population has proven difficult due to low numbers, heterogeneous cell populations, substantial phenotypic differences between mouse and human cells, and the high plasticity seen in iTregs. These current limitations have prevented …

Crosstalk Between Gastrointestinal Epithelial Cells And Resident Microbiota Promotes Immune Homeostasis, Eric William Rogier

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

The gastrointestinal tract houses one of the most dense and diverse communities of bacteria on the planet. The mutualistic relationship between the host and commensal microbe permits the microbe an ideal environment to grow and provides the host with increased caloric intake, maturation of the adaptive immune system, and resistance against invading pathogens. To maintain a system in which both parties benefit, the epithelium has evolved numerous strategies to ensure epithelial cells respond to microbes appropriately and that potentially hazardous commensals remain distanced from the soma proper. Breakdown of these propitiating mechanisms elicits unchecked inflammation and can lead to pathology …

Hiv Rna Suppression And Immune Restoration: Can We Do Better?, Marilia Rita Pinzone, Michelino Di Rosa, Bruno Cacopardo, Giuseppe Nunnari

Department of Microbiology and Immunology Faculty Papers

HAART has significantly changed the natural history of HIV infection: patients receiving antiretrovirals are usually able to control viremia, even though not all virological responders adequately recover their CD4+ count. The reasons for poor immune restoration are only partially known and they include genetic, demographic and immunologic factors. A crucial element affecting immune recovery is immune activation, related to residual viremia; indeed, a suboptimal virological control (i.e., low levels of plasma HIV RNA) has been related with higher levels of chronic inflammation and all-cause mortality. The sources of residual viremia are not yet completely known, even though the most important …

Evidence That The Density Of Self Peptide-Mhc Ligands Regulates T-Cell Receptor Signaling., Nadia Anikeeva, Dimitry Gakamsky, Jørgen Schøller, Yuri Sykulev

Department of Microbiology and Immunology Faculty Papers

Noncognate or self peptide-MHC (pMHC) ligands productively interact with T-cell receptor (TCR) and are always in a large access over the cognate pMHC on the surface of antigen presenting cells. We assembled soluble cognate and noncognate pMHC class I (pMHC-I) ligands at designated ratios on various scaffolds into oligomers that mimic pMHC clustering and examined how multivalency and density of the pMHCs in model clusters influences the binding to live CD8 T cells and the kinetics of TCR signaling. Our data demonstrate that the density of self pMHC-I proteins promotes their interaction with CD8 co-receptor, which plays a critical role …

Chloroviruses: Not Your Everyday Plant Virus, James L. Van Etten, David D. Dunigan

Nebraska Center for Virology: Faculty Publications

Viruses infecting higher plants are among the smallest viruses known and typically have four to ten protein-encoding genes. By contrast, many viruses that infect algae (classified in the virus family Phycodnaviridae) are among the largest viruses found to date and have up to 600 protein- encoding genes. This brief review focuses on one group of plaque-forming phycodnaviruses that infect unicellular chlorella-like green algae. The prototype chlorovirus PBCV-1 has more than 400 protein-encoding genes and 11 tRNA genes. About 40% of the PBCV-1 encoded proteins resemble proteins of known function including many that are completely unexpected for a virus. In many …

Molecular Genetic And Biochemical Characterization Of The Vaccinia Virus I3 Protein, The Replicative Single-Stranded Dna Binding Protein, Matthew D. Greseth, Kathleen A. Boyle, Matthew S. Bluma, Bethany Unger, Matthew S. Wiebe, Jamaria A. Soares-Martins, Nadi T. Wickramasekera, James Wahlberg, Paula Traktman

Nebraska Center for Virology: Faculty Publications

Vaccinia virus, the prototypic poxvirus, efficiently and faithfully replicates its approximately 200-kb DNA genome within the cytoplasm of infected cells. This intracellular localization dictates that vaccinia virus encodes most, if not all, of its own DNA replication machinery. Included in the repertoire of viral replication proteins is the I3 protein, which binds to single-stranded DNA (ssDNA) with great specificity and stability and has been presumed to be the replicative ssDNA binding protein (SSB). We substantiate here that I3 colocalizes with bromodeoxyuridine (BrdU)-labeled nascent viral genomes and that these genomes accumulate in cytoplasmic factories that are delimited by membranes derived from …

Lineage-Specific Differences Between Human And Simian Immunodeficiency Virus Regulation Of Gp120 Trimer Association And Cd4 Binding, Andrés Finzi, Beatriz Pacheco, Shi-Hua Xiang, Marie Pancera, Alon Herschhorn, Liping Wang, Xing Zeng, Anik Desormeaux, Peter D. Kwong, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

Metastable conformations of the gp120 and gp41 envelope glycoproteins of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) must be maintained in the unliganded state of the envelope glycoprotein trimer. Binding of gp120 to the primary receptor, CD4, triggers the transition to an open conformation of the trimer, promoting interaction with the CCR5 chemokine receptor and ultimately leading to gp41-mediated virus-cell membrane fusion and entry. Topological layers in the gp120 inner domain contribute to gp120-trimer association in the unliganded state and to CD4 binding. Here we describe similarities and differences between HIV-1 and SIVmac gp120. In both …

Subunit Organization Of The Membrane-Bound Hiv-1 Envelope Glycoprotein Trimer, Youdong Mao, Liping Wang, Christopher Gu, Alon Herschhorn, Shi-Hua Xiang, Hillel Haim, Xinzhen Yang, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

The trimeric human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) spike is a molecular machine that mediates virus entry into host cells and is the sole target for virus-neutralizing antibodies. The mature Env spike results from cleavage of a trimeric gp160 precursor into three gp120 and three gp41 subunits. Here we describe an ~11-Å cryo-EM structure of the trimeric HIV-1 Env precursor in its unliganded state. The three gp120 and three gp41 subunits form a cage-like structure with an interior void surrounding the trimer axis. Interprotomer contacts are limited to the gp41 transmembrane region, the torus-like gp41 ectodomain, and …

Comparative Analysis Of The Fusion Efficiency Elicited By The Envelope Glycoprotein V1–V5 Regions Derived From Human Immunodeficiency Virus Type 1 Transmitted Perinatally, Hongyan Guo, Levon Abrahamyan, Chang Liu, Mackenzie Waltke, Yunqi Geng, Qimin Chen, Charles Wood, Xiaohong Kong

Nebraska Center for Virology: Faculty Publications

Understanding the properties of viruses preferentially establishing infection during perinatal transmission of human immunodeficiency virus type 1 (HIV-1) is critical for the development of effective measures to prevent transmission. A previous study demonstrated that the newly transmitted viruses (in infants) of chronically infected mother–infant pairs (MIPs) were fitter in terms of growth, which was imparted by their envelope (Env) glycoprotein V1–V5 regions, than those in the corresponding chronically infected mothers. In order to investigate whether the higher fitness of transmitted viruses was conferred by their higher entry efficiency directed by the V1–V5 regions during perinatal transmission, the fusogenicity of Env …

Antibody Responses To Lytic And Latent Human Herpesvirus 8 Antigens Among Hiv-Infected Patients In Central China, Tiejun Zhang, Na He, Yingying Ding, Qingwu Jiang, Charles Wood

Nebraska Center for Virology: Faculty Publications

Human herpesvirus 8 (HHV8) is an important opportunistic infection of HIV/AIDS. However, very little is known about antibody seropositivities to HHV8 lytic and latent antigens among HIVinfected patients in China. Therefore, a cross-sectional study was conducted to explore HHV8 serostatus among 316 HIV-infected patients in a rural area of central China. The antibody seropositivity to HHV8 ORF65 (lytic) and LANA (latent) antigens was 12.7% and 10.4%, respectively. Patients who were naïve to antiretroviral therapy (ART) were more likely to be seropositive for antibodies to ORF65 (OR: 3.79; 95% CI: 1.71–8.42) and LANA (OR: 3.77; 95% CI: 1.55–9.14) than patients receiving …

Heme Oxygenase-1 Regulates The Immune Response To Influenza Virus Infection And Vaccination In Aged Mice, Nathan W. Cummins, Eric A. Weaver, Shannon M. May, Anthony J. Croatt, Oded Foreman, Richard B. Kennedy, Gregory A. Polan, Michael A. Barry, Karl A. Nath, Andrew D. Badley

Nebraska Center for Virology: Faculty Publications

Underlying mechanisms of individual variation in severity of influenza infection and response to vaccination are poorly understood. We investigated the effect of reduced heme oxygenase-1 (HO-1) expression on vaccine response and outcome of influenza infection. HO-1-deficient and wild-type (WT) mice (kingdom, Animalia; phylum, Chordata; genus/species, Mus musculus) were infected with influenza virus A/PR/8/34 with or without prior vaccination with an adenoviral-based influenza vaccine. A genome-wide association study evaluated the expression of single-nucleotide polymorphisms (SNPs) in the HO-1 gene and the response to influenza vaccination in healthy humans. HO-1-deficient mice had decreased survival after influenza infection compared to WT mice (median …