bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multigene DNA Priming-Boosting Vaccines Protect Macaques from Acute CD4+-T-Cell Depletion after Simian-Human Immunodeficiency Virus SHIV89.6P Mucosal Challenge
Authors: Doria-Rose N. A. , Ohlen C. , Polacino P. , Pierce C. C. , Hensel M. T. , Kuller L. , Mulvania T. , Anderson D. , Greenberg P. D. , Hu S.-L. , Haigwood N. L. 
Published: October 2003

ABSTRACTWe evaluated four priming-boosting vaccine regimens for the highly pathogenic simian human immunodeficiency virus SHIV89.6P inMacaca nemestrina. Each regimen included gene gun delivery of a DNA vaccine expressing all SHIV89.6 genes plus Env gp160 of SHIV89.6P. Additional components were two recombinant vaccinia viruses, expressing SHIV89.6 Gag-Pol or Env gp160, and inactivated SHIV89.6 virus. We compared (i) DNA priming/DNA boosting, (ii) DNA priming/inactivated virus boosting, (iii) DNA priming/vaccinia virus boosting, and (iv) vaccinia virus priming/DNA boosting versus sham vaccines in groups of 6 macaques. Prechallenge antibody responses to Env and Gag were strongest in the groups that received vaccinia virus priming or boosting. Cellular immunity to SHIV89.6 peptides was measured by enzyme-linked immunospot assay; strong responses to Gag and Env were found in 9 of 12 vaccinia virus vaccinees and 1 of 6 DNA-primed/inactivated-virus-boosted animals. Vaccinated macaques were challenged intrarectally with 50 50% animal infectious doses of SHIV89.6P 3 weeks after the last immunization. All animals became infected. Five of six DNA-vaccinated and 5 of 6 DNA-primed/particle-boosted animals, as well as all 6 controls, experienced severe CD4+-T-cell loss in the first 3 weeks after infection. In contrast, DNA priming/vaccinia virus boosting and vaccinia virus priming/DNA boosting vaccines both protected animals from disease: 11 of 12 macaques had no loss of CD4+T cells or moderate declines. Virus loads in plasma at the set point were significantly lower in vaccinia virus-primed/DNA-boosted animals versus controls (P= 0.03). We conclude that multigene vaccines delivered by a combination of vaccinia virus and gene gun-delivered DNA were effective against SHIV89.6P viral challenge inM. nemestrina.
Caprine Arthritis-Encephalitis Virus Envelope Surface Glycoprotein Regions Interacting with the Transmembrane Glycoprotein: Structural and Functional Parallels with Human Immunodeficiency Virus Type 1 gp120
Authors: Hötzel Isidro , Cheevers William P. 
Published: October 2003

ABSTRACT
A sequence similarity between surface envelope glycoprotein (SU) gp135 of the lentiviruses maedi-visna virus and caprine arthritis-encephalitis virus (CAEV) and human immunodeficiency virus type 1 (HIV-1) gp120 has been described. The regions of sequence similarity are in the second and fifth conserved regions of gp120, and the similarity is highest in sequences coinciding with β-strands 4 to 8 and 25, which are located in the most virion-proximal region of the gp120 inner domain. A subset of this structure, formed by gp120 β-strands 4, 5, and 25, is conserved in most or all lentiviruses. Because of the orientation of gp120 on the virion, this highly conserved virion-proximal region of the gp120 core may interact with the transmembrane glycoprotein (TM) together with the amino and carboxy termini of full-length gp120. Therefore, interactions between SU and TM of lentiviruses may be structurally related. Here we tested whether the amino acid residues in the putative virion-proximal region of CAEV gp135 comprising putative β-strands 4, 5, and 25, as well as its amino and carboxy termini, are important for stable interactions with TM. An amino acid change at gp135 position 119 or 521, located in the turn between putative β-strands 4 and 5 and near β-strand 25, respectively, specifically disrupted the epitope recognized by monoclonal antibody 29A. Thus, similar to the corresponding gp120 regions, these gp135 residues are located in close proximity to each other in the folded protein, supporting the hypothesis of a structural similarity between the gp120 virion-proximal inner domain and gp135. Amino acid changes in the amino- and carboxy-terminal and putative virion-proximal regions of gp135 increased gp135 shedding from the cell surface, indicating that these gp135 regions are involved in interactions with TM. Our results indicate structural and functional parallels between CAEV gp135 and HIV-1 gp120 that may be more broadly applicable to the SU of other lentiviruses.
Replication of an E1B 55-Kilodalton Protein-Deficient Adenovirus (ONYX-015) Is Restored by Gain-of-Function Rather than Loss-of-Function p53 Mutants
Authors: Hann Byron , Balmain Allan 
Published: October 2003

ABSTRACT

ONYX-015 (
dl
1520) is an E1B 55-kilodalton protein-deficient replicating adenovirus that is currently in clinical trials as an antitumor agent. On the basis of the observation that the
E1B 55kD
gene product is able to bind to and inactivate p53, ONYX-015's mechanism of action is proposed to involve selective replication in and killing of p53-deficient cells. While its efficacy as a therapeutic agent appears evident, the virus's mechanism of cellular selectivity, including a possible role of p53 in this regard, is less clear. Indeed, there have been a number of recent reports suggesting that the p53 status of target cells does not reliably predict ONYX-015 replication or cell killing. To address the role of p53 in ONYX-015 selectivity, we have undertaken a rigorous analysis of the behavior of this virus in small airway-derived primary human epithelial cells expressing either dominant-negative or gain-of-function mutant
p53
genes. Examination of small airway epithelial cells expressing a variety of
p53
mutant alleles revealed that while all were able to inhibit endogenous p53 activity, only one allele examined, 248W, demonstrated a markedly increased ability to facilitate ONYX-015 replication. This allele is a member of a group of
p53
mutants (know as class I mutants) characterized by retention of global structural conformation but loss of DNA-binding activity. These observations indicate that the nature of the
p53
mutation affects ONYX-015 replication, help reconcile disparate published findings, and may provide criteria by which to direct clinical application of ONYX-015.
Optimal Induction of T-Cell Responses against Hepatitis C Virus E2 by Antigen Engineering in DNA Immunization
Authors: Youn Jin-Won , Park Su-Hyung , Cho Jae Ho , Sung Young Chul 
Published: October 2003

ABSTRACTAlthough DNA immunization is a safe and efficient method for inducing cellular immune responses, it generates relatively weak and slow immune responses. Here, we investigated the effect of hepatitis C virus (HCV) antigen modifications on the induction of T-cell responses in DNA immunization. It is likely that the strength of T-cell responses has an inverse relationship with the length of the insert DNA. Interestingly, a mixture of several plasmids carrying each gene induced a higher level of T-cell responses than a single plasmid expressing a long polyprotein. Moreover, the presence of a transmembrane domain in HCV E2 resulted in stronger T-cell responses against E2 protein than its absence. Taken together, our results indicate that the tailored modifications of DNA-encoded antigens are capable of optimizing the induction of T-cell responses which is required for eliminating the cells chronically infected with highly variable viruses such as HCV and human immunodeficiency virus.
The 3′ End of Norwalk Virus mRNA Contains Determinants That Regulate the Expression and Stability of the Viral Capsid Protein VP1: a Novel Function for the VP2 Protein
Authors: Bertolotti-Ciarlet Andrea , Crawford Sue E. , Hutson Anne M. , Estes Mary K. 
Published: October 2003

ABSTRACT

Norwalk virus (NV) is the prototype strain of a group of noncultivable human caliciviruses responsible for epidemic outbreaks of acute gastroenteritis. The capsid protein VP1 is synthesized from a subgenomic RNA that contains two open reading frames (ORFs), ORF2 and ORF3, and the 3′ untranslated region (UTR). ORF2 and ORF3 code for the capsid protein (VP1) and a small structural basic protein (VP2), respectively. We discovered that the yields of virus-like particles (VLPs) composed of VP1 are significantly reduced when this protein is expressed from ORF2 alone. To determine how the 3′ terminus of the NV subgenomic RNA regulates VP1 expression, we compared VP1 expression levels by using recombinant baculovirus constructs containing different 3′ elements. High VP1 levels were detected by using a recombinant baculovirus that contained ORF2, ORF3, and the 3′UTR (ORF2+3+3′UTR). In contrast, expression of VP1 from constructs that lacked the 3′UTR (ORF2+3), ORF3 (ORF2+3′UTR), or both (ORF2 alone) was highly reduced. Elimination of VP2 synthesis from the subgenomic RNA by mutation resulted in VP1 levels similar to those obtained with the ORF2 construct alone, suggesting a
cis
role for VP2 in upregulation of VP1 expression levels. Comparisons of the kinetics of RNA and capsid protein expression levels by using constructs with or without ORF3 or the 3′UTR revealed that the 3′UTR increased the levels of VP1 RNA, whereas the presence of VP2 resulted in increased levels of VP1. Furthermore, VP2 increased VP1 stability and protected VP1 from disassembly and protease degradation. The increase in VP1 expression levels caused by the presence of VP2 in
cis
was also observed in mammalian cells.
Changes in Mumps Virus Gene Sequence Associated with Variability in Neurovirulent Phenotype
Authors: Rubin Steven A. , Amexis Georgios , Pletnikov Mikhail , Vanderzanden Jacqueline , Mauldin Jeremy , Sauder Christian , Malik Tahir , Chumakov Konstantin , Carbone Kathryn M. 
Published: October 2003

ABSTRACTMumps virus is highly neurotropic and, prior to widespread vaccination programs, was the major cause of viral meningitis in the United States. Nonetheless, the genetic basis of mumps virus neurotropism and neurovirulence was until recently not understood, largely due to the lack of an animal model. Here, nonneurovirulent (Jeryl Lynn vaccine) and highly neurovirulent (88-1961 wild type) mumps virus strains were passaged in human neural cells or in chicken fibroblast cells with the goal of neuroadapting or neuroattenuating the viruses, respectively. When tested in our rat neurovirulence assay against the respective parental strains, a Jeryl Lynn virus variant with an enhanced propensity for replication (neurotropism) and damage (neurovirulence) in the brain and an 88-1961 wild-type virus variant with decreased neurotropic and neurovirulent properties were recovered. To determine the molecular basis for the observed differences in neurovirulence and neuroattenuation, the complete genomes of the parental strains and their variants were fully sequenced. A comparison at the nucleotide level associated three amino acid changes with enhanced neurovirulence of the neuroadapted vaccine strain: one each in the nucleoprotein, matrix protein, and polymerase and three amino acid changes with reduced neurovirulence of the neuroattenuated wild-type strain: one each in the fusion protein, hemagglutinin-neuraminidase protein, and polymerase. The potential role of these amino acid changes in neurotropism, neurovirulence, and neuroattenuation is discussed.
Identification of a Human Papillomavirus Type 16-Specific Epitope on the C-Terminal Arm of the Major Capsid Protein L1
Authors: Carter Joseph J. , Wipf Greg C. , Benki Sarah F. , Christensen Neil D. , Galloway Denise A. 
Published: October 2003

ABSTRACT
To characterize epitopes on human papillomavirus (HPV) virus-like particles (VLPs), a panel of mutated HPV-16 VLPs was created. Each mutated VLP had residues substituted from HPV-31 or HPV-52 L1 sequences to the HPV-16 L1 backbone. Mutations were created on the HPV-31 and −52 L1 proteins to determine if HPV-16 type-specific recognition could be transferred. Correct folding of the mutated proteins was verified by resistance to trypsin digestion and by binding to one or more conformation-dependent monoclonal antibodies. Several of the antibodies tested were found to bind to regions already identified as being important for HPV VLP recognition (loops DE, EF, FG, and HI). Sequences at both ends of the long FG loop (amino acids 260 to 290) were required for both H16.V5 and H16.E70 reactivity. A new antibody-binding site was discovered on the C-terminal arm of L1 between positions 427 and 445. Recognition of these residues by the H16.U4 antibody suggests that this region is surface exposed and supports a recently proposed molecular model of HPV VLPs.
Murine Cytomegalovirus m41 Open Reading Frame Encodes a Golgi-Localized Antiapoptotic Protein
Authors: Brune Wolfram , Nevels Michael , Shenk Thomas 
Published: October 2003

ABSTRACT
Viruses have evolved various strategies to prevent premature apoptosis of infected host cells. Some of the viral genes mediating antiapoptotic functions have been identified by their homology to cellular genes, but others are structurally unrelated to genes of known function. In this study, we used a random, unbiased approach to identify such genes in the murine cytomegalovirus genome. From a library of random transposon insertion mutants, a mutant virus that caused premature cell death was isolated. The transposon was inserted within open reading frame m41. An independently constructed m41 deletion mutant showed the same phenotype, whereas deletion mutants lacking the adjacent genes m40 and M42 did not. Apoptosis occurred in different cell types, could be blocked by caspase inhibitors, and did not require p53. Within the murine cytomegalovirus genome, m41, m40, and m39 form a small cluster of genes of unknown function. They are homologous to r41, r40, and r39 of rat cytomegalovirus, but lack sequence homology to UL41, UL40, and UL37 exon 1 (UL37x1) which are located at the corresponding positions of the human cytomegalovirus genome. Unlike UL37x1 of human cytomegalovirus, which encodes a mitochondrion-localized inhibitor of apoptosis that is essential for virus replication, m41 encodes a protein that localizes to the Golgi apparatus. The murine cytomegalovirus m41 product is the first example of a Golgi-localized protein that prevents premature apoptosis and thus extends the life span of infected cells.
Cell Surface Expression of Major Histocompatibility Complex Class I Molecules Is Reduced in Hepatitis C Virus Subgenomic Replicon-Expressing Cells
Authors: Tardif Keith D. , Siddiqui Aleem 
Published: October 2003

ABSTRACTThe hepatitis C virus (HCV) causes chronic hepatitis in most infected individuals by evading host immune defenses. In this investigation, we show that HCV-infected cells may go undetected in the immune system by suppressing major histocompatibility complex (MHC) class I antigen presentation to cytotoxic T lymphocytes. Cells expressing HCV subgenomic replicons have lower MHC class I cell surface expression. This is due to reduced levels of properly folded MHC class I molecules. HCV replicons induce endoplasmic reticulum (ER) stress (K. Tardif, K. Mori, and A. Siddiqui, J. Virol. 76:7453-7459, 2002), which results from a decline in protein glycosylation. Decreasing protein glycosylation can disrupt protein folding, preventing the assembly of MHC class I molecules. This results in the accumulation of unfolded MHC class I. Therefore, the persistence and pathogenesis of HCV may depend upon the ER stress-mediated interference of MHC class I assembly and cell surface expression.
Murine Leukemia Virus Particle Assembly Quantitated by Fluorescence Microscopy: Role of Gag-Gag Interactions and Membrane Association
Authors: Andrawiss Mariam , Takeuchi Yasuhiro , Hewlett Lindsay , Collins Mary 
Published: October 2003

ABSTRACT

In order to track the assembly of murine leukemia virus (MLV), we used fluorescence microscopy to visualize particles containing Gag molecules fused to fluorescent proteins (FPs). Gag-FP chimeras budded from cells to produce fluorescent spots, which passed through the same pore-size filters and sedimented at the same velocity as authentic MLV. N-terminal myristylation of Gag-FPs was necessary for particle formation unless wild-type Gag was coexpressed. By labeling nonmyristylated Gag with yellow FP and wild-type Gag with cyan FP, we could quantitate the coincorporation of two proteins into single particles. This experiment showed that nonmyristylated Gag was incorporated into mixed particles at approximately 50% the efficiency of wild-type Gag. Mutations that inhibit Gag-Gag interactions (K. Alin and S. P. Goff, Virology
216:
418-424, 1996; K. Alin and S. P. Goff, Virology
222:
339-351, 1996) were then introduced into the capsid (CA) region of Gag-FPs. The mutations P150L and R119C/P133L inhibited fluorescent particle formation by these Gag-FPs, but Gag-FPs containing these mutations could be efficiently incorporated into particles when coexpressed with wild-type Gag. When these mutations were introduced into nonmyristylated Gag-FPs, no incorporation into particles in the presence of wild-type Gag was detected. These data suggest that two independent mechanisms, CA interactions and membrane association following myristylation, cooperate in MLV Gag assembly and budding.
A Locus on Mouse Chromosome 6 That Determines Resistance to Herpes Simplex Virus Also Influences Reactivation, While an Unlinked Locus Augments Resistance of Female Mice
Authors: Lundberg Patric , Welander Paula , Openshaw Harry , Nalbandian Christina , Edwards Carl , Moldawer Lyle , Cantin Edouard 
Published: October 2003

ABSTRACTDuring studies to determine a role for tumor necrosis factor (TNF) in herpes simplex virus type 1 (HSV-1) infection using TNF receptor null mutant mice, we discovered a genetic locus, closely linked to the TNF p55 receptor (Tnfrsf1a) gene on mouse chromosome 6 (c6), that determines resistance or susceptibility to HSV-1. We named this locus the herpes resistance locus,Hrl, and showed that it also mediates resistance to HSV-2.Hrlhas at least two alleles,Hrlr, expressed by resistant strains like C57BL/6 (B6), andHrls, expressed by susceptible strains like 129S6 (129) and BALB/c. AlthoughHrlis inherited as an autosomal dominant gene, resistance to HSV-1 is strongly sex biased such that female mice are significantly more resistant than male mice. Analysis of backcrosses between resistant B6 and susceptible 129 mice revealed that a second locus, tentatively named the sex modifier locus,Sml, functions to augment resistance of female mice. Besides determining resistance,Hrlis one of several genes involved in the control of HSV-1 replication in the eye and ganglion. Remarkably,Hrlalso affects reactivation of HSV-1, possibly by interaction with some unknown gene(s). We showed thatHrlis distinct fromCmv1, the gene that determines resistance to murine cytomegalovirus, which is encoded in the major NK cell complex just distal of p55 on c6.Hrlhas been mapped to a roughly 5-centimorgan interval on c6, and current efforts are focused on obtaining a high-resolution map forHrl.
Mutational Inactivation of Two Distinct Negative RNA Elements in the Human Papillomavirus Type 16 L2 Coding Region Induces Production of High Levels of L2 in Human Cells
Authors: Öberg Daniel , Collier Brian , Zhao Xiaomin , Schwartz Stefan 
Published: October 2003

ABSTRACT

Here we show that the 5′ end and the middle region of the L2 coding sequence of human papillomavirus type 16 contain strong inhibitory RNA sequences termed inhibitory regions I and II. This is in contrast to L1, which contains one inhibitory region in the 5′ end of the coding region. Inhibitory regions I and II acted in
cis
to reduce L2 mRNA levels and to inhibit the use of the mRNA. In tandem, the two regions reduced L2 mRNA production to undetectable levels. Specific mutational inactivation of the two inhibitory elements in the 5′ end and in the middle region of L2 by the introduction of nucleotide substitutions that changed the nucleotide sequence but not the protein sequence resulted in production of high levels of L2 mRNA and protein. In contrast to L2, a partial L1 mutant in which only the first one third of L1 was mutated produced levels of L1 mRNA and protein similar to those in a full L1 mutant. In addition, the constitutive transport element of simian retrovirus type 1 overcomes the effect of the inhibitory sequences of L1 but not L2.
Distinct Domains in the Adenovirus E3 RIDα Protein Are Required for Degradation of Fas and the Epidermal Growth Factor Receptor
Authors: Zanardi Tom A. , Yei Soonpin , Lichtenstein Drew L. , Tollefson Ann E. , Wold William S. M. 
Published: October 2003

ABSTRACTAdenovirus (Ad) types 2 and 5 encode at least five proteins within the E3 transcription unit that help the virus evade the immune system. Two such proteins, RIDα (formerly E3-10.4K) and RIDβ (formerly E3-14.5K), form the RID (receptor internalization and degradation) complex (formerly E3-10.4K/14.5K). RID mediates clearance from the cell surface and lysosomal degradation of a number of important members in the tumor necrosis factor receptor (TNFR) superfamily and the receptor tyrosine kinase receptor family. Affected receptors include Fas, TRAIL (TNF-related apoptosis-inducing ligand) receptor 1 (TR1), TR2, and epidermal growth factor receptor (EGFR). Degradation of Fas and TRAIL receptors protects Ad-infected cells from apoptosis. To investigate the mechanism of action of RIDα, 14 mutant RIDα proteins, each containing a three- to five-amino-acid deletion, were constructed and then expressed from the E3 region of a replication-competent recombinant Ad in the same context as wild-type RIDα. Each mutant protein was characterized with regard to five physical properties associated with wild-type RIDα, namely, protein stability, proteolytic cleavage, insertion into the membrane, complex formation with RIDβ, and transport to the cell surface. Additionally, the mutant proteins were tested for their ability to mediate internalization and degradation of EGFR and Fas and to protect cells from Fas-mediated apoptosis. The majority of mutant RIDα proteins (8 out of 14) were physically similar to wild-type RIDα. With regard to functional characteristics, the cytoplasmic domain of RIDα is largely unimportant for receptor internalization and degradation and the extracellular domain of RIDα is important for down-regulation of EGFR but not Fas.