bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Papillomavirus Type 16 (HPV-16) Virus-Like Particle L1-Specific CD8
+
Cytotoxic T Lymphocytes (CTLs) Are Equally Effective as E7-Specific CD8
+
CTLs in Killing Autologous HPV-16-Positive Tumor Cells in Cervical Cancer Patients: Implications for L1 Dendritic Cell-Based Therapeutic Vaccines
Authors: Bellone Stefania , El-Sahwi Karim , Cocco Emiliano , Casagrande Francesca , Cargnelutti Marilisa , Palmieri Michela , Bignotti Eliana , Romani Chiara , Silasi Dan-Arin , Azodi Masoud , Schwartz Peter E. , Rutherford Thomas J. , Pecorelli Sergio , Santin Alessandro D. 
Published: April 2009

ABSTRACT

Papillomavirus-like particles (VLPs) based on L1 capsid protein represent a promising prophylactic vaccine against human papillomavirus (HPV) infections. However, cell-mediated immune responses against this antigen are believed to be of limited therapeutic value in established HPV-infected cervical lesions and, for this reason, have not been intensively investigated in cervical cancer patients. In this study we analyzed and quantified by real-time PCR (RT-PCR) the RNA expression levels of E6, E7, and L1 genes in flash-frozen HPV-16 cervical carcinomas. In addition, the kinetics of expression of E6, E7, and L1 in HPV-16-infected primary cell lines established as long-term cultures in vitro was also evaluated at RNA and protein levels. Finally, in order to evaluate the therapeutic potential of L1-specific CD4
+
and CD8
+
T lymphocytes responses in cervical cancer patients, L1 VLP-loaded dendritic cells (DCs) were used to stimulate peripheral blood lymphocytes from cervical cancer patients and such responses were compared to those elicited by the E7 oncoprotein. We show that 22 of 22 (100%) flash-frozen cervical biopsy samples collected from HPV-16-positive cervical cancer patients harbor L1, in addition to E6 and E7 RNA, as detected by RT-PCR. E7 RNA copy number (mean, 176.2) was significantly higher in HPV-16-positive cervical cancers compared to the E6 RNA copy number (mean, 47.3) and the L1 copy number (mean, 58.3) (
P
< 0.0001 and
P
< 0.001, respectively). However, no significant differences in expression levels between E6 and L1 were found. Kinetic studies of E6, E7, and L1 RNA and protein expression levels in primary tumors showed a sharp reduction in L1 expression after multiple in vitro passages compared to E6 and E7. Autologous DCs pulsed with HPV-16 VLPs or recombinant full-length E7 elicited strong type 1 L1- and E7-specific responses in CD4
+
and CD8
+
T cells from cervical cancer patients. Importantly, L1 VLP-specific CD8
+
T lymphocytes expressed strong cytolytic activity against autologous tumor cells and were as effective as E7-specific cytotoxic T lymphocytes in lysing naturally HPV-16-infected autologous tumor cells. Taken together, these data demonstrate a consistent expression of L1 in primary cervical tumors and the possibility of inducing effective L1/tumor-specific CD4
+
and CD8
+
T-lymphocyte responses in patients harboring HPV-infected cervical cancer. These results may have important implications for the treatment of patients harboring established HPV-infected lesions with L1 VLPs or combined E7/L1 DC-based vaccinations.
Herpesvirus Capsid Association with the Nuclear Pore Complex and Viral DNA Release Involve the Nucleoporin CAN/Nup214 and the Capsid Protein pUL25
Authors: Pasdeloup David , Blondel Danielle , Isidro Anabela L. , Rixon Frazer J. 
Published: April 2009

ABSTRACT
After penetrating the host cell, the herpesvirus capsid is transported to the nucleus along the microtubule network and docks to the nuclear pore complex before releasing the viral DNA into the nucleus. The viral and cellular interactions involved in the docking process are poorly characterized. However, the minor capsid protein pUL25 has recently been reported to be involved in viral DNA uncoating. Here we show that herpes simplex virus type 1 (HSV-1) capsids interact with the nucleoporin CAN/Nup214 in infected cells and that RNA silencing of CAN/Nup214 delays the onset of viral DNA replication in the nucleus. We also show that pUL25 interacts with CAN/Nup214 and another nucleoporin, hCG1, and binds to the pUL36 and pUL6 proteins, two other components of the herpesvirus particle that are known to be important for the initiation of infection and viral DNA release. These results identify CAN/Nup214 as being a nuclear receptor for the herpesvirus capsid and pUL25 as being an interface between incoming capsids and the nuclear pore complex and as being a triggering element for viral DNA release into the nucleus.
Identification of Varicella-Zoster Virus-Specific CD8 T Cells in Patients after T-Cell-Depleted Allogeneic Stem Cell Transplantation
Authors: van der Heiden Pim L. J. , de Boer Renate , van der Steen Dirk M. , Kester Michel G. D. , van der Hoorn Menno W. A. G. , Haarman Wilmy M. E. , Barnby-Porritt Helen E. , Fry Jeremy W. , Napper C. E. , Marijt Erik W. A. , Willemze Roel , Falkenburg J. H. Frederik , Heemskerk Mirjam H. M. 
Published: April 2009

ABSTRACTTo study the role of CD8 T cells in the control of varicella-zoster virus (VZV) reactivation, we developed multimeric major histocompatibility complexes to identify VZV-specific CD8 T cells. Potential HLA-A2 binding peptides from the putative immediate-early 62 protein (IE62) of VZV were tested for binding, and peptides with sufficient binding capacity were used to generate pentamers. Patients with VZV reactivation following stem cell transplantation were screened with these pentamers, leading to the identification of the first validated class I-restricted epitope of VZV. In 42% of HLA-A2 patients following VZV reactivation, these IE62-ALW-A2 T cells could be detected ex vivo.
Hepatitis B Virus Core Gene Mutations Which Block Nucleocapsid Envelopment
Authors: Koschel Matthias , Oed Daniela , Gerelsaikhan Tudevdagwa , Thomssen Reiner , Bruss Volker 
Published: April 2009

ABSTRACT

Recently we generated a panel of hepatitis B virus core gene mutants carrying single insertions or deletions which allowed efficient expression of the core protein in bacteria and self-assembly of capsids. Eleven of these mutations were introduced into a eukaryotic core gene expression vector and characterized by
trans
complementation of a core-negative HBV genome in cotransfected human hepatoma HuH7 cells. Surprisingly, four mutants (two insertions [EFGA downstream of A11 and LDTASALYR downstream of R39] and two deletions [Y38-R39-E40 and L42]) produced no detectable capsids. The other seven mutants supported capsid formation and pregenome packaging/viral minus- and plus-strand-DNA synthesis but to different levels. Four of these seven mutants (two insertions [GA downstream of A11 and EHCSP downstream of P50] and two deletions [S44 and A80]) allowed virion morphogenesis and secretion. The mutant carrying a deletion of A80 at the tip of the spike protruding from the capsid was hepatitis B virus core antigen negative but wild type with respect to virion formation, indicating that this site might not be crucial for capsid-surface protein interactions during morphogenesis. The other three nucleocapsid-forming mutants (one insertion [LS downstream of S141] and two deletions [T12 and P134]) were strongly blocked in virion formation. The corresponding sites are located in the part of the protein forming the body of the capsid and not in the spike. These mutations may alter sites on the particle which contact surface proteins during envelopment, or they may block the appearance of a signal for the transport or the maturation of the capsid which is linked to viral DNA synthesis and required for envelopment.
RNA Dimerization Defect in a Rous Sarcoma Virus Matrix Mutant
Authors: Parent Leslie J. , Cairns Tina M. , Albert Jessica A. , Wilson Carol B. , Wills John W. , Craven Rebecca C. 
Published: April 2009

ABSTRACT
The retrovirus matrix (MA) sequence of the Gag polyprotein has been shown to contain functions required for membrane targeting and binding during particle assembly and budding. Additional functions for MA have been proposed based on the existence of MA mutants in Rous sarcoma virus (RSV), murine leukemia virus, human immunodeficiency virus type 1, and human T-cell leukemia virus type 1 that lack infectivity even though they release particles of normal composition. Here we describe an RSV MA mutant with a surprising and previously unreported phenotype. In the mutant known as Myr1E, the small membrane-binding domain of the Src oncoprotein has been added as an N-terminal extension of Gag. While Myr1E is not infectious, full infectivity can be reestablished by a single amino acid substitution in the Src sequence (G2E), which eliminates the addition of myristic acid and the membrane-binding capacity of this foreign sequence. The presence of myristic acid at the N terminus of the Myr1E Gag protein does not explain its replication defect, because other myristylated derivatives of RSV Gag are fully infectious (e.g., Myr2 [C. R. Erdie and J. W. Wills, J. Virol. 64:5204–5208, 1990]). Biochemical analyses of Myr1E particles reveal that they contain wild-type levels of the Gag cleavage products, Env glycoproteins, and reverse transcriptase activity when measured on an exogenous template. Genomic RNA incorporation appears to be mildly reduced compared to the wild-type level. Unexpectedly, RNA isolated from Myr1E particles is monomeric when analyzed on nondenaturing Northern blots. Importantly, the insertional mutation does not lie within previously identified dimer linkage sites. In spite of the dimerization defect, the genomic RNA from Myr1E particles serves efficiently as a template for reverse transcription as measured by an endogenous reverse transcriptase assay. In marked contrast, after infection of avian cells, the products of reverse transcription are nearly undetectable. These findings might be explained either by the loss of a normal function of MA needed in the formation or stabilization of RNA dimers or by the interference in such events by the mutant MA molecules. It is possible that Myr1E viruses package a single copy of viral RNA.
B7 Costimulation Is Critical for Antibody Class Switching and CD8+Cytotoxic T-Lymphocyte Generation in the Host Response to Vesicular Stomatitis Virus
Authors: McAdam Alexander J. , Farkash Evan A. , Gewurz Benjamin E. , Sharpe Arlene H. 
Published: April 2009

ABSTRACTAntibody and cytotoxic T-lymphocyte (CTL) responses have critical roles in eliminating many viral infections. In addition to stimulation of the T-cell receptor, T cells require costimulatory signals to respond optimally. We evaluated the role of B7 costimulatory molecules (B7-1 and B7-2) in the immune response to viral infection using vesicular stomatitis virus (VSV) and mice lacking either B7-1 or B7-2 or both molecules. Mice lacking both B7-1 and B7-2 had essentially no anti-VSV immunoglobulin G1 (IgG1) response, decreased IgG2a responses, and normal IgM responses, while mice lacking either B7-1 or B7-2 had unaltered anti-VSV antibody responses compared to wild-type mice. Depletion of CD4+cells further reduced the IgG2a response in mice lacking both B7 molecules, suggesting that CD4−cells may supply help for IgG2a in the absence of B7 costimulation. The absence of both B7 molecules profoundly reduced generation of both primary and secondary VSV-specific class I major histocompatibility complex (MHC)-restricted CTL, whereas VSV-specific CTL responses in mice lacking either B7-1 or B7-2 were similar to those of wild-type animals. Class I MHC-restricted CTL in wild-type mice were not dependent on CD4+cells, suggesting that the failure of CTL in the absence of B7s is due to a lack of B7 costimulation directly to the CD8+CTL. These data demonstrate that B7-1 and B7-2 have critical, overlapping functions in the antibody and CTL responses to this viral infection.
A Comprehensive Approach to Mapping the Interacting Surfaces of Murine Amphotropic and Feline Subgroup B Leukemia Viruses with Their Cell Surface Receptors
Authors: Tailor Chetankumar S. , Nouri Ali , Kabat David 
Published: April 2009

ABSTRACT

Because mutations in envelope glycoproteins of retroviruses or in their cell surface receptors can eliminate function by multiple mechanisms, it has been difficult to unambiguously identify sites for their interactions by site-directed mutagenesis. Recently, we developed a gain-of-function approach to overcome this problem. Our strategy relies on the fact that feline leukemia virus subgroup B (FeLV-B) and amphotropic murine leukemia virus (A-MLV) have closely related gp70 surface envelope glycoproteins and use related Na
+
-dependent phosphate symporters, Pit1 and Pit2, respectively, as their receptors. We previously observed that FeLV-B/A-MLV envelope glycoprotein chimeras spliced between the variable regions VRA and VRB were unable to use Pit1 or Pit2 as a receptor but could efficiently use specific Pit1/Pit2 chimeras. The latter study suggested that the VRA of A-MLV and FeLV-B functionally interact with the presumptive extracellular loops 4 and 5 (ECL4 and -5) of their respective receptors, whereas VRB interacts with ECL2. We also found that FeLV-B gp70 residues F60 and P61 and A-MLV residues Y60 and V61 in the first disulfide-bonded loop of VRA were important for functional interaction with the receptor's ECL4 or -5. We have now extended this approach to identify additional VRA and VRB residues that are involved in receptor recognition. Our studies imply that FeLV-B VRA residues F60 and P61 interact with the Pit1 ECL5 region, whereas VRA residues 66 to 78 interact with Pit1 ECL4. Correspondingly, A-MLV VRA residues Y60 and V61 interact with the Pit2 ECL5 region, whereas residues 66 to 78 interact with Pit2 ECL4. Similar studies that focused on the gp70 VRB implicated residues 129 to 139 as contributing to specific interactions with the receptor ECL2. These results identify three regions of gp70 that interact in a specific manner with distinct portions of their receptors, thereby providing a map of the functionally interacting surfaces.
Identification of a Short, Hydrophilic Amino Acid Sequence Critical for Origin Recognition by the Bovine Papillomavirus E1 Protein
Authors: Gonzalez Annika , Bazaldua-Hernandez Cynthia , West Michael , Woytek Kelly , Wilson Van G. 
Published: April 2009

ABSTRACT
The E1 protein of bovine papillomavirus (BPV) is a site-specific DNA binding protein that recognizes an 18-bp inverted repeat element in the viral origin of replication. Sequence-specific DNA binding function maps to the region from approximately amino acids 140 to 300, and isolated polypeptides containing this region have been shown to retain origin binding in vitro. To investigate the sequence and structural characteristics which contribute to sequence-specific binding, the primary sequence of this region was examined for conserved features. The BPV E1 DNA binding domain (E1DBD) contains three major hydrophilic domains (HR1, amino acids 179–191; HR2, amino acids 218 to 230; and HR3, amino acids 241 to 252), of which only HR1 and HR3 are conserved among papillomavirus E1 proteins. E1DBD proteins with lysine-to-alanine mutations in HR1 and HR3 were severely impaired for DNA binding function in vitro, while a lysine-to-alanine mutation in HR2 had a minimal effect on DNA binding. Mutation of adjacent threonine residues in HR1 (T187 and T188) revealed that these two amino acids made drastically different contributions to DNA binding, with the T187 mutant being severely defective for origin binding whereas the T188 mutant was only mildly affected. Helical wheel projections of HR1 predict that T187 is on the same helical face as the critical lysine residues whereas T188 is on the opposing face, which is consistent with their respective contributions to DNA binding activity. To examine E1 binding in vivo, a yeast one-hybrid system was developed. Both full-length E1 and the E1DBD polypeptide were capable of specifically interacting with the E1 binding site in the context of the yeast genome, and HR1 was also critical for this in vivo interaction. Overall, our results indicate that HR1 is essential for origin binding by E1, and the features and properties of HR1 suggest that it may be part of a recognition sequence that mediates specific E1-nucleotide contacts.
Simplified Strategy for Detection of Recombinant Human Immunodeficiency Virus Type 1 Group M Isolates by
gag/env
Heteroduplex Mobility Assay
Authors: Heyndrickx Leo , Janssens Wouter , Zekeng Léopold , Musonda Rosemary , Anagonou Séverin , Van der Auwera Gert , Coppens Sandra , Vereecken Katleen , De Witte Ko , Van Rampelbergh Rian , Kahindo Maina , Morison Linda , McCutchan Francine E. , Carr Jean K. , Albert Jan , Essex Max , Goudsmit Jaap , Asjö Birgitta , Salminen Mika , Buvé Anne ,   Study Group on Heterogeneity of HIV Epidemics in African Cities, van der Groen Guido 
Published: April 2009

ABSTRACT

We developed a heteroduplex mobility assay in the
gag
gene (
gag
HMA) for the identification of group M subtypes A to H. The assay covers the region coding for amino acid 132 of p24 to amino acid 20 of p7 (according to human immunodeficiency virus type 1 [HIV-1] ELI, 460 bp). The
gag
HMA was compared with sequencing and phylogenetic analysis of an evaluation panel of 79 HIV-1 group M isolates isolated from infected individuals from different geographic regions. Application of
gag
HMA in combination with
env
HMA on 252 HIV-1- positive plasma samples from Bénin, Cameroon, Kenya, and Zambia revealed a high prevalence of a variety of intersubtype recombinants in Yaoundé, Cameroon (53.8%); Kisumu, Kenya (26.8%); and Cotonou, Bénin (41%); no recombinants were identified among the samples from Ndola, Zambia. The AG
IbNG
circulating recombinant form, as determined by
gag
HMA, was found to be the most common intersubtype recombinant in Yaoundé (39.4%) and Cotonou (38.5%). Using a one-tube reverse transcriptase PCR protocol, this
gag
HMA in combination with
env
HMA is a useful tool for rapidly monitoring the prevalence of the various genetic subtypes as well as of recombinants of HIV-1. Moreover, this technology can easily be applied in laboratories in developing countries.
Canine Adenovirus Vectors: an Alternative for Adenovirus-Mediated Gene Transfer
Authors: Kremer Eric J. , Boutin Sylvie , Chillon Miguel , Danos Olivier 
Published: April 2009

ABSTRACTPreclinical studies have shown that gene transfer following readministration of viral vectors is often inefficient due to the presence of neutralizing antibodies. Vectors derived from ubiquitous human adenoviruses may have limited clinical use because preexisting humoral and cellular immunity is found in 90% of the population. Furthermore, risks associated with the use of human adenovirus vectors, such as the need to immunosuppress or tolerize patients to a potentially debilitating virus, are avoidable if efficient nonhuman adenovirus vectors are feasible. Plasmids containing recombinant canine adenovirus (CAV) vectors from which the E1 region had been deleted were generated and transfected into a CAV E1-transcomplementing cell line. Vector stocks, with titers greater than or equal to those obtained with human adenovirus vectors, were free of detectable levels of replication-competent CAV and had a low particle-to-transduction unit ratio. CAV vectors were replication defective in all cell lines tested, transduced human-derived cells at an efficiency similar to that of a comparable human adenovirus type 5 vector, and are amenable to in vivo use. Importantly, 49 of 50 serum samples from healthy individuals did not contain detectable levels of neutralizing CAV antibodies.
Plasmid-Driven Formation of Influenza Virus-Like Particles
Authors: Neumann Gabriele , Watanabe Tokiko , Kawaoka Yoshihiro 
Published: April 2009

ABSTRACT

We established a plasmid-based system for generating infectious influenza virus-like particles entirely from cloned cDNAs. Human embryonic kidney cells (293T) were transfected with plasmids encoding the influenza A virus structural proteins and with a plasmid encoding an influenza virus-like viral RNA (vRNA) which contained an antisense copy of the cDNA for green fluorescence protein (GFP) flanked by an RNA polymerase I promoter and terminator. Intracellular transcription of the latter construct by RNA polymerase I generated GFP vRNA that was packaged into influenza virus-like particles. This system, which produced more than 10
4
infectious particles per ml of supernatant, would be useful in studies of influenza virus replication and particle formation. It might also benefit efforts in vaccine production and in the development of improved gene therapy vectors.
Immune Complexes Containing Human Immunodeficiency Virus Type 1 Primary Isolates Bind to Lymphoid Tissue B Lymphocytes and Are Infectious for T Lymphocytes
Authors: Jakubik Jocelyn J. , Saifuddin Mohammed , Takefman Daniel M. , Spear Gregory T. 
Published: April 2009

ABSTRACTThis study investigated the interaction of tonsil B lymphocytes with immune complexes containing human immunodeficiency virus (HIV IC) primary isolates and the infectivity of the B cell-bound HIV IC. Treatment of virus with a source of antibody and complement increased HIV IC binding to B cells by 5.6-fold. Most of the HIV IC that bound to B cells were not internalized but remained on the cell surface and were gradually released over 72 h. Cell-bound HIV IC were highly infectious for T cells while virus released by cultured B cells was only slightly infectious. Removal of HIV IC from the B-cell surface by protease treatment reduced the infection of T cells to near-background levels, indicating that infectious virus remained on the B-cell surface. These studies show that B lymphocytes can carry and transfer infectious HIV IC to T cells and thus suggest a novel mode of infection of T cells in lymphoid tissue that could be important for pathogenesis during HIV infection.
COLLECTIVE ELECTRONIC EXCITATIONS IN SYSTEMS EXHIBITING QUANTUM WELL STATES
Authors: POLITANO ANTONIO , CHIARELLO GENNARO 
Published: April 2009

We present high-resolution electron energy loss spectroscopy (HREELS) measurements on surface plasmon (SP) dispersion in systems exhibiting quantum well states (QWS), i.e. Na / Cu (111), Ag / Cu (111), and Ag / Ni (111). Our results demonstrate that the dominant coefficient of SP dispersion for thin and layer-by-layer Ag films presenting QWS is quadratic even at small q||, in contrast with previous measurements on Ag semi-infinite media and Ag thin films deposited on Si (111). We suggest that this behavior is due to screening effects enhanced by the presence of QWS shifting the position of the centroid of the induced charge less inside the geometrical surface compared with Ag surfaces and Ag / Si (111). For ultrathin Ag films, i.e. two layers, the dispersion was found to be not positive, as theoretically predicted. Annealing of the Ag film caused an enhancement of the free-electron character of the QWS, thus inducing a negative linear term of the dispersion curve of the SP. Moreover, we report the first experimental evidence of chemical interface damping in thin films for K / Ag / Ni (111). As regards Na / Cu (111), we found a different dispersion curve compared with thick Na films, thus confirming the enhanced screening by Na QWS. Results reported here should shed light on the influence of QWS on dynamical screening phenomena in thin films.