bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antimicrobial Peptides from Amphibian Skin Potently Inhibit Human Immunodeficiency Virus Infection and Transfer of Virus from Dendritic Cells to T Cells
Authors: VanCompernolle Scott E. , Taylor R. Jeffery , Oswald-Richter Kyra , Jiang Jiyang , Youree Bryan E. , Bowie John H. , Tyler Michael J. , Conlon J. Michael , Wade David , Aiken Christopher , Dermody Terence S. , KewalRamani Vineet N. , Rollins-Smith Louise A. , Unutmaz Derya 
Published: September 2005

ABSTRACT
Topical antimicrobicides hold great promise in reducing human immunodeficiency virus (HIV) transmission. Amphibian skin provides a rich source of broad-spectrum antimicrobial peptides including some that have antiviral activity. We tested 14 peptides derived from diverse amphibian species for the capacity to inhibit HIV infection. Three peptides (caerin 1.1, caerin 1.9, and maculatin 1.1) completely inhibited HIV infection of T cells within minutes of exposure to virus at concentrations that were not toxic to target cells. These peptides also suppressed infection by murine leukemia virus but not by reovirus, a structurally unrelated nonenveloped virus. Preincubation with peptides prevented viral fusion to target cells and disrupted the HIV envelope. Remarkably, these amphibian peptides also were highly effective in inhibiting the transfer of HIV by dendritic cells (DCs) to T cells, even when DCs were transiently exposed to peptides 8 h after virus capture. These data suggest that amphibian-derived peptides can access DC-sequestered HIV and destroy the virus before it can be transferred to T cells. Thus, amphibian-derived antimicrobial peptides show promise as topical inhibitors of mucosal HIV transmission and provide novel tools to understand the complex biology of HIV capture by DCs.
Decreased Virus Population Diversity in
p53
-Null Mice Infected with Weakly Oncogenic Abelson Virus
Authors: Marchlik Erica , Kalman Richard , Rosenberg Naomi 
Published: September 2005

ABSTRACT

The Abelson murine leukemia virus (Ab-MLV), like other retroviruses that contain v-
onc
genes, arose following a recombination event between a replicating retrovirus and a cellular oncogene. Although experimentally validated models have been presented to address the mechanism by which oncogene capture occurs, very little is known about the events that influence emerging viruses following the recombination event that incorporates the cellular sequences. One feature that may play a role is the genetic makeup of the host in which the virus arises; a number of host genes, including oncogenes and tumor suppressor genes, have been shown to affect the pathogenesis of many murine leukemia viruses. To examine how a host gene might affect an emerging v-
onc
gene-containing retrovirus, we studied the weakly oncogenic Ab-MLV-P90A strain, a mutant that generates highly oncogenic variants in vivo, and compared the viral populations in normal mice and mice lacking the
p53
tumor suppressor gene. While variants arose in both
p53

+/+

and
p53
−
/
−
tumors, the samples from the wild-type animals contained a more diverse virus population. Differences in virus population diversity were not observed when wild-type and null animals were infected with a highly oncogenic wild-type strain of Ab-MLV. These results indicate that
p53
, and presumably other host genes, affects the selective forces that operate on virus populations in vivo and likely influences the evolution of oncogenic retroviruses such as Ab-MLV.
Influence of Fiber Detargeting on Adenovirus-Mediated Innate and Adaptive Immune Activation
Authors: Schoggins John W. , Nociari Marcelo , Philpott Nicola , Falck-Pedersen Erik 
Published: September 2005

ABSTRACTThe major adenovirus (Ad) capsid proteins hexon, penton, and fiber influence the efficiency and tropism of gene transduction by Ad vectors. Fiber is the high-affinity receptor binding protein that serves to mediate cell attachment in vitro when using coxsackie-adenovirus receptor (CAR)-containing cell lines. This contrasts with transduction efficiency in macrophages or dendritic cells that lack high concentrations of CAR. To determine how fiber influences gene transduction and immune activation in a murine model, we have characterized Ad type 5 (Ad5) vectors with two classes of chimeric fiber, CAR binding and non-CAR binding. In a systemic infection, Ad5 fiber contributes to DNA localization and vector transduction in hepatic tissue. However, the majority of vector localization is due to Ad5 fiber-specific functions distinct from CAR binding. CAR-directed transduction occurs but at a modest level. In contrast to CAR binding vectors, the F7 and F7F41S non-CAR-binding vectors demonstrate a 2-log decrease in hepatic transduction, with a 10-fold decrease in the amount of vector DNA localizing to the hepatic tissue. To characterize the innate response to early infection using fiber chimeric vectors, intrahepatic cytokine and chemokine mRNAs were quantified 5 hours postinfection. Tumor necrosis factor alpha mRNA levels resulting from Ad5 fiber infections were elevated compared to viruses expressing serotype 7 or 41 fiber. Levels of chemokine mRNA (gamma interferon-inducible protein 10, T-cell activation gene 3, and macrophage inflammatory protein 1β) were 10- to 20-fold higher with CAR binding vectors (Ad5 and F41T) than with non-CAR-binding vectors (F7 and F7F41S). In spite of quantitative differences in vector localization and innate activation, fiber pseudotyping did not significantly change the outcome of anti-Ad adaptive immunity. All vectors were cleared with the same kinetics as wild-type Ad5 vectors, and each induced neutralizing antibody. Although non-CAR-binding vectors were impaired in transduction by nearly 2 orders of magnitude, the level of antitransgene immunity was the same for each of the vectors. Using primary bone marrow-derived macrophages and dendritic cells, we demonstrate that transduction, induction of cytokine/chemokine, and phenotypic maturation of these antigen-presenting cells are independent of fiber content. Our data support a model where fiber-mediated hepatic localization enhances innate responses to virus infection but minimally impacts on adaptive immunity.
Single Amino Acid Substitutions in the Severe Acute Respiratory Syndrome Coronavirus Spike Glycoprotein Determine Viral Entry and Immunogenicity of a Major Neutralizing Domain
Authors: Yi Christopher E. , Ba Lei , Zhang Linqi , Ho David D. , Chen Zhiwei 
Published: September 2005

ABSTRACT
Neutralizing antibodies (NAbs) against severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) spike (S) glycoprotein confer protection to animals experimentally infected with the pathogenic virus. We and others previously demonstrated that a major mechanism for neutralizing SARS-CoV was through blocking the interaction between the S glycoprotein and the cellular receptor angiotensin-converting enzyme 2 (ACE2). In this study, we used in vivo electroporation DNA immunization and a pseudovirus-based assay to functionally evaluate immunogenicity and viral entry. We characterized the neutralization and viral entry determinants within the ACE2-binding domain of the S glycoprotein. The deletion of a positively charged region SΔ(422-463) abolished the capacity of the S glycoprotein to induce NAbs in mice vaccinated by in vivo DNA electroporation. Moreover, the SΔ(422-463) pseudovirus was unable to infect HEK293T-ACE2 cells. To determine the specific residues that contribute to related phenotypes, we replaced eight basic amino acids with alanine. We found that a single amino acid substitution (R441A) in the full-length S DNA vaccine failed to induce NAbs and abolished viral entry when pseudoviruses were generated. However, another substitution (R453A) abolished viral entry while retaining the capacity for inducing NAbs. The difference between R441A and R453A suggests that the determinants for immunogenicity and viral entry may not be identical. Our findings provide direct evidence that these basic residues are essential for immunogenicity of the major neutralizing domain and for viral entry. Our data have implications for the rational design of vaccine and antiviral agents as well as for understanding viral tropism.
Attenuation of Marek's Disease Virus by Deletion of Open Reading Frame
RLORF4
but Not
RLORF5a
Authors: Jarosinski Keith W. , Osterrieder Nikolaus , Nair Venugopal K. , Schat Karel A. 
Published: September 2005

ABSTRACT

Marek's disease (MD) in chickens is caused by the alphaherpesvirus MD virus (MDV) and is characterized by the development of lymphoblastoid tumors in multiple organs. The recent identification and cloning of
RLORF4
and the finding that four of six attenuated strains of MDV contained deletions within
RLORF4
suggested that it is involved in the attenuation process of MDV. To assess the role of
RLORF4
in MD pathogenesis, its coding sequence was deleted in the pRB-1B bacterial artificial chromosome clone. Additionally,
RLORF5a
was deleted separately to examine its importance for oncogenesis. The sizes of plaques produced by MDV reconstituted from pRB-1BΔRLORF5a (rRB-1BΔRLORF5a) were similar to those produced by the parental pRB-1B virus (rRB-1B). In contrast, virus reconstituted from pRB-1BΔRLORF4 (rRB-1BΔRLORF4) produced significantly larger plaques. Replication of the latter virus in cultured cells was higher than that of rRB-1B or rRB-1BΔRLORF5a using quantitative PCR (qPCR) assays. In vivo, both deletion mutants and rRB-1B replicated at comparable levels at 4, 7, and 10 days postinoculation (p.i.), as determined by virus isolation and qPCR assays. At 14 days p.i., the number of PFU of virus isolated from chickens infected with rRB-1BΔRLORF4 was comparable to that from chickens infected with highly attenuated RB-1B and significantly lower than that from rRB-1B-infected birds. The number of tumors and kinetics of tumor production in chickens infected with rRB-1BΔRLORF5a were similar to those of P2a chickens infected with rRB-1B. In stark contrast, none of the chickens inoculated with rRB-1BΔRLORF4 died up to 13 weeks p.i.; however, two chickens had tumors at the termination of the experiment. The data indicate that
RLORF4
is involved in attenuation of MDV, although the function of
RLORF4
is still unknown.
Characterization of an Alternate Form of Newcastle Disease Virus Fusion Protein
Authors: Pantua Homer , McGinnes Lori W. , Leszyk John , Morrison Trudy G. 
Published: September 2005

ABSTRACT

The sequence and structure of the Newcastle disease virus (NDV) fusion (F) protein are consistent with its classification as a type 1 glycoprotein. We have previously reported, however, that F protein can be detected in at least two topological forms with respect to membranes in both a cell-free protein synthesizing system containing membranes and infected COS-7 cells (J. Virol.
77:
1951-1963, 2003). One form is the classical type 1 glycoprotein, while the other is a polytopic form in which approximately 200 amino acids of the amino-terminal end as well as the cytoplasmic domain (CT) are translocated across membranes. Furthermore, we detected CT sequences on surfaces of F protein-expressing cells, and antibodies specific for these sequences inhibited red blood cell fusion to hemagglutinin-neuraminidase and F protein-expressing cells, suggesting a role for surface-expressed CT sequences in cell-cell fusion. Extending these findings, we have found that the alternate form of the F protein can also be detected in infected and transfected avian cells, the natural host cells of NDV. Furthermore, the alternate form of the F protein was also found in virions released from both infected COS-7 cells and avian cells by Western analysis. Mass spectrometry confirmed its presence in virions released from avian cells. Two different polyclonal antibodies raised against sequences of the CT domain of the F protein slowed plaque formation in both avian and COS-7 cells. Antibody specific for the CT domain also inhibited single-cycle infections, as detected by immunofluorescence of viral proteins in infected cells. The potential roles of this alternate form of the NDV F protein in infection are discussed.
Interferon Regulatory Factor 5 Represses Expression of the Epstein-Barr Virus Oncoprotein LMP1: Braking of the IRF7/LMP1 Regulatory Circuit
Authors: Ning Shunbin , Huye Leslie E. , Pagano Joseph S. 
Published: September 2005

ABSTRACT
We have reported evidence for a positive regulatory circuit between interferon regulatory factor 7 (IRF7) and the Epstein-Barr virus (EBV) oncoprotein 1 (LMP1) (S. Ning, A. M. Hahn, and J. S. Pagano, J. Virol. 77:9359-9368, 2003). To explore a possible braking mechanism for this circuit, several type II EBV-infected cell lines that express different levels of LMP1 and IRF7 proteins and therefore are convenient for studying modulation of expression of LMP1 were analyzed. Endogenous levels of IRF7 and LMP1 were directly correlated. Transient expression of an IRF7 dominant-negative mutant decreased LMP1 levels. Endogenous IRF5 and IRF7 proteins were shown to physically associate in EBV-positive cells. Transient expression of IRF5 decreased activation of the LMP1 promoter by IRF7 in a dose-dependent manner. Finally, transfection of either an IRF5 dominant-negative construct or IRF5 small interfering RNA in these cells resulted in increases in endogenous levels of LMP1. These results indicate that IRF5 can downregulate IRF7's induction of expression of LMP1 most likely by interacting with IRF7 and provide a means of modulating a regulatory circuit between IRF7 and LMP1.
Combined Effect of CCR5-Δ32 Heterozygosity and the CCR5 Promoter Polymorphism −2459 A/G on CCR5 Expression and Resistance to Human Immunodeficiency Virus Type 1 Transmission
Authors: Hladik Florian , Liu Huanliang , Speelmon Emily , Livingston-Rosanoff Devon , Wilson Sean , Sakchalathorn Polachai , Hwangbo Yon , Greene Benjamin , Zhu Tuofu , McElrath M. Juliana 
Published: September 2005

ABSTRACT

Exposed seronegative individuals (ES) with persistent high-risk sexual behavior may be less susceptible to human immunodeficiency virus type 1 (HIV-1) infection because they carry the chemokine receptor (CR) gene alleles CCR5 open reading frame (ORF) Δ32, CCR5 promoter −2459G, or CCR2 ORF 64I (CCR2-64I), all of which have been found to diminish HIV-1 infectivity and/or disease progression. To investigate this, we determined the haplotypes for these three genetic loci in 93 ES and 247 low-risk control individuals. To test if protective haplotypes exert their effect by modulating CR expression, we measured the protein expression of CCR5 and CXCR4 on circulating CD4
+
T cells and CD14
+
monocytes in 71 ES and 92 controls. To avoid investigator bias, the analysis was performed without knowledge of each subject's risk and genotype. The CCR5 −2459G allele was significantly enriched in ES Caucasian men, who constituted the majority (84%) of the ES cohort, compared to the control Caucasian men (
P
= 0.02). This increase was mostly attributable to a higher frequency of the −2459 A/G versus the −2459 A/A genotype in individuals heterozygous for the Δ32 allele (
P
= 0.012). No protective influence of the CCR2-64I allele was observed. The haplotypes CCR5 ORF Δ32/CCR5 −2459A (in complete linkage disequilibrium) and CCR5 ORF wt/CCR5 −2459G had a cumulative negative effect on the expression of CCR5, since we measured significantly reduced CCR5 densities on both T-helper cells and monocytes only when both haplotypes were present. Densities of CCR5 on lymphocytes and monocytes were correlated (
r
= 0.59;
P
< 0.0001), indicating concordance of CCR5 expression patterns across different cell types. We conclude that the CCR5 ORF Δ32/wt-CCR5 −2459 A/G genotype combination offers an advantage in resisting sexual HIV-1 transmission and that this effect is mediated by a relative paucity of CCR5 on potential target cells of HIV-1.
Borna Disease Virus Replication in Organotypic Hippocampal Slice Cultures from Rats Results in Selective Damage of Dentate Granule Cells
Authors: Mayer Daniel , Fischer Heike , Schneider Urs , Heimrich Bernd , Schwemmle Martin 
Published: September 2005

ABSTRACTIn the hippocampus of Borna disease virus (BDV)-infected newborn rats, dentate granule cells undergo progressive cell death. BDV is noncytolytic, and the pathogenesis of this neurodevelopmental damage in the absence of immunopathology remains unclear. A suitable model system to study early events of the pathology is lacking. We show here that organotypic hippocampal slice cultures from newborn rat pups are a suitable ex vivo model to examine BDV neuropathogenesis. After challenging hippocampal slice cultures with BDV, we observed a progressive loss of calbindin-positive granule cells 21 to 28 days postinfection. This loss was accompanied by reduced numbers of mossy fiber boutons when compared to mock-infected cultures. Similarly, the density of dentate granule cell axons, the mossy fiber axons, appeared to be substantially reduced. In contrast, hilar mossy cells and pyramidal neurons survived, although BDV was detectable in these cells. Despite infection of dentate granule cells 2 weeks postinfection, the axonal projections of these cells and the synaptic connectivity patterns were comparable to those in mock-infected cultures, suggesting that BDV-induced damage of granule cells is a postmaturation event that starts after mossy fiber synapses are formed. In summary, we find that BDV infection of rat organotypic hippocampal slice cultures results in selective neuronal damage similar to that observed with infected newborn rats and is therefore a suitable model to study BDV-induced pathology in the hippocampus.
Vaccinia Virus H3L Envelope Protein Is a Major Target of Neutralizing Antibodies in Humans and Elicits Protection against Lethal Challenge in Mice
Authors: Davies D. Huw , McCausland Megan M. , Valdez Conrad , Huynh Devan , Hernandez Jenny E. , Mu Yunxiang , Hirst Siddiqua , Villarreal Luis , Felgner Philip L. , Crotty Shane 
Published: September 2005

ABSTRACT

The smallpox vaccine is the prototypic vaccine, yet the viral targets critical for vaccine-mediated protection remain unclear in humans. We have produced protein microarrays of a near-complete vaccinia proteome and used them to determine the major antigen specificities of the human humoral immune response to the smallpox vaccine (Dryvax). H3L, an intracellular mature virion envelope protein, was consistently recognized by high-titer antibodies in the majority of human donors, particularly after secondary immunization. We then focused on examining H3L as a valuable human antibody target. Purified human anti-H3L antibodies exhibited substantial vaccinia virus-neutralizing activity in vitro (50% plaque reduction neutralization test [PRNT
50
] = 44 μg/ml). Mice also make an immunodominant antibody response to H3L after vaccination with vaccinia virus, as determined by vaccinia virus protein microarray. Mice were immunized with recombinant H3L protein to examine H3L-specific antibody responses in greater detail. H3L-immunized mice developed high-titer vaccinia virus-neutralizing antibodies (mean PRNT
50
= 1:3,760). Importantly, H3L-immunized mice were subsequently protected against lethal intranasal challenges with 1 or 5 50% lethal doses (LD
50
) of pathogenic vaccinia virus strain WR, demonstrating the in vivo value of an anti-H3L response. To formally demonstrate that neutralizing anti-H3L antibodies are protective in vivo, we performed anti-H3L serum passive-transfer experiments. Mice receiving H3L-neutralizing antiserum were protected from a lethal challenge with 3 LD
50
of vaccinia virus strain WR (5/10 versus 0/10;
P
< 0.02). Together, these data show that H3L is a major target of the human anti-poxvirus antibody response and is likely to be a key contributor to protection against poxvirus infection and disease.
Involvement of Cytoskeletal Components in BK Virus Infectious Entry
Authors: Eash Sylvia , Atwood Walter J. 
Published: September 2005

ABSTRACT
Posttransplant reactivation of BK virus (BKV) in the renal allograft progresses to polyomavirus-associated nephropathy in 1% to 8% of kidney recipients. Graft dysfunction and loss in 30% to 45% of polyomavirus-associated nephropathy-affected patients are secondary to extensive tubular epithelial cell injury induced by the lytic replication of BKV. The early events in productive BKV infection are not thoroughly understood. We have previously shown that BKV enters cells by caveola-mediated endocytosis. In this report we examine the role of microfilaments and microtubules during early viral infection. Our results show that BKV infection of Vero cells is sensitive to nocodazole-induced disassembly of the microtubule network for the initial 8 hours following virus binding. In contrast, suppression of microtubule turnover with the stabilizing agent paclitaxel has no effect on BKV infectivity. Selective disassembly of the actin filaments with latrunculin A does not impede BKV infection, while inhibition of microfilament dynamics with jasplakinolide results in reduced numbers of viral antigen-positive cells. These data demonstrate that BKV, like other polyomaviruses, relies on an intact microtubule network during early infection. BKV, however, does not share the requirement with the closely related JC virus for an intact actin cytoskeleton during intracellular transport.
Rab9 GTPase Is Required for Replication of Human Immunodeficiency Virus Type 1, Filoviruses, and Measles Virus
Authors: Murray James L. , Mavrakis Manos , McDonald Natalie J. , Yilla Mamadi , Sheng Jinsong , Bellini William J. , Zhao Lijun , Le Doux Joseph M. , Shaw Michael W. , Luo Chi-Cheng , Lippincott-Schwartz Jennifer , Sanchez Anthony , Rubin Donald H. , Hodge Thomas W. 
Published: September 2005

ABSTRACT

Rab proteins and their effectors facilitate vesicular transport by tethering donor vesicles to their respective target membranes. By using gene trap insertional mutagenesis, we identified Rab9, which mediates late-endosome-to-
trans
-Golgi-network trafficking, among several candidate host genes whose disruption allowed the survival of Marburg virus-infected cells, suggesting that Rab9 is utilized in Marburg replication. Although Rab9 has not been implicated in human immunodeficiency virus (HIV) replication, previous reports suggested that the late endosome is an initiation site for HIV assembly and that TIP47-dependent trafficking out of the late endosome to the
trans
-Golgi network facilitates the sorting of HIV Env into virions budding at the plasma membrane. We examined the role of Rab9 in the life cycles of HIV and several unrelated viruses, using small interfering RNA (siRNA) to silence Rab9 expression before viral infection. Silencing Rab9 expression dramatically inhibited HIV replication, as did silencing the host genes encoding TIP47, p40, and PIKfyve, which also facilitate late-endosome-to-
trans
-Golgi vesicular transport. In addition, silencing studies revealed that HIV replication was dependent on the expression of Rab11A, which mediates
trans
-Golgi-to-plasma-membrane transport, and that increased HIV Gag was sequestered in a CD63
+
endocytic compartment in a cell line stably expressing Rab9 siRNA. Replication of the enveloped Ebola, Marburg, and measles viruses was inhibited with Rab9 siRNA, although the nonenveloped reovirus was insensitive to Rab9 silencing. These results suggest that Rab9 is an important cellular target for inhibiting diverse viruses and help to define a late-endosome-to-plasma-membrane vesicular transport pathway important in viral assembly.