Search results for "Virology"
showing 10 items of 2354 documents
Avarol restores the altered prostaglandin and leukotriene metabolism in monocytes infected with human immunodeficiency virus type 1
1991
Abstract Infection of monocytes with human immunodeficiency virus type 1 (HIV-1) (strain Ada-M) caused increased levels of leukotriene B 4 (LTB 4 ) and prostaglandin E 2 (PGE 2 ) in vitro. These two products result from the activities of the two enzymes cyclooxygenase and 5-lipoxygenase. The addition of the sesquiterpenoid hydroquinone Avarol, an HIV inhibitor, strongly reduced the levels of LTB 4 and PGE 2 via inhibition of both cyclooxygenase and lipoxygenase in monocytes. The 50% inhibition concentrations (IC 50 ) for the enzymes were determined to be 2.26 μM (cyclooxygenase) and 1.97 μM (lipoxygenase). A 50% reduction of the extent of PGE 2 and LTB 4 production in HIV-infected monocytes…
Abstract A110: Mutant MHC class II epitopes drive therapeutic immune responses to cancer
2016
Abstract Mutations are regarded as ideal targets for cancer immunotherapy. As neoepitopes with strict lack of expression in any healthy tissue, they are expected to be safe and could bypass the central tolerance mechanisms. Recent advances in nucleic acid sequencing technologies have revolutionized the field of genomics, allowing the readily targeting of mutated neoantigens for personalized cancer vaccination. We demonstrated in three independent murine tumor models that a considerable fraction of non-synonymous cancer mutations is immunogenic and that unexpectedly the immunogenic mutanome is pre-dominantly recognized by CD4+ T cells. RNA vaccination with such MHC class II restricted immuno…
Repetitive nucleotide sequencing of a dispensable DNA segment in a clonal population of African swine fever virus
1991
Abstract Repetitive nucleotide sequencing of a dispensable genomic segment of a clonal population of African swine fever (ASF) virus has been carried out to estimate the mutant frequency to neutral alleles. Since no mutations have been detected in a total of 54026 nucleotides screened, the maximum mutant frequency is 5.5 × 10 −5 substitutions/nucleotide (95% confidence level). The result renders very unlikely the occurrence of hypermutational events during ASF virus DNA replication, at least within the selected DNA fragment.
Late steps of parvoviral infection induce changes in cell morphology.
2008
Previously, virus-induced non-filopodial extensions have not been encountered in connection with viral infections. Here, we report emergence of long extensions protruding from Norden laboratory feline kidney (NLFK) and A72 (canine fibroma) cells infected with canine parvovirus for 72 h. These extensions significantly differ in length and number from those appearing in control cells. The most striking feature in the extensions is the length, reaching up to 130 microm, almost twice the average length of a healthy NLFK cell. In A72 cells, the extensions were even longer, up to 200 microm. The results presented here also suggest that the events leading to the growth of these extensions start ea…
The effect of genetic complementation on the fitness and diversity of viruses spreading as collective infectious units
2019
Viruses can spread collectively using different types of structures such as extracellular vesicles, virion aggregates, polyploid capsids, occlusion bodies, and even cells that accumulate virions at their surface, such as bacteria and dendritic cells. Despite the mounting evidence for collective spread, its implications for viral fitness and diversity remain poorly understood. It has been postulated that, by increasing the cellular multiplicity of infection, collective spread could enable mutually beneficial interactions among different viral genetic variants. One such interaction is genetic complementation, whereby deleterious mutations carried by different genomes are compensated. Here, we…
Human papillomavirus frequency in oral epithelial lesions
2005
BACKGROUND: Oral human papillomavirus (HPV) prevalence varies according to geographical occurrence, the type of lesion, and the method of diagnosis. The polymerase chain reaction method (PCR) appears to be more sensitive and can be easily applicable to epidemiologic studies. OBJECTIVES: To determine the frequency of HPV and its genotypes in oral lesions among patients attending a reference clinic of a university hospital. METHODS: PCR was performed to identify HPV DNA from samples of oral epithelial lesions in 80 patients. For HPV DNA amplification, MY09/MY11 consensus primers were used and specific genotypes were identified through restriction fragment of length polymorphism (RFLP) pattern…
Effective infection, apoptotic cell killing and gene transfer of human hepatoma cells but not primary hepatocytes by parvovirus H1 and derived vector…
2001
Autonomous parvoviruses preferentially replicate in and kill in vitro–transformed cells and reduce the incidence of spontaneous and implanted tumors in animals. Because of these natural oncotropic and oncolytic properties, parvoviruses deserve to be considered as potential antitumor vectors. Here, we assessed whether parvovirus H1 is able to kill human hepatoma cells by induction of apoptosis but spares primary human liver cells, and whether the former cells can efficiently be transduced by H1 virus–based vectors. Cell death, infectivity, and transgene transduction were investigated in Hep3B, HepG2, and Huh7 cells and in primary human hepatocytes with natural and recombinant H1 virus. All h…
Ub surprised: viral ovarian tumor domain proteases remove ubiquitin and ISG15 conjugates.
2007
Ubiquitin (Ub) and interferon stimulated gene product 15 (ISG15) reversibly conjugate to proteins via a conserved LRLRGG C-terminal motif, mediating important innate antiviral responses. The ovarian tumor (OTU) domain represents a superfamily of predicted proteases found in eukaryotic, bacterial and viral proteins, some of which have Ub-deconjugating activity. We show that the OTU domain-containing proteases of nairoviruses and arteriviruses hydrolyze Ub and ISG15 from cellular target proteins. This broad activity contrasts with the target specificity of known mammalian OTU domain-containing proteins. The biological significance of this activity of viral OTU domain-containing proteases was …
Novel recombinant GII.P16_GII.13 and GII.P16_GII.3 norovirus strains in Italy.
2014
Novel norovirus strains are continuously emerging worldwide. Molecular investigation and phylogenetic analysis identified GII.P16 recombinant noroviruses from the stools of four Italian children with gastroenteritis. The capsid gene was characterized as either GII.13 or GII.3. The GII.P16_GII.13 Italian strains were closely related to German strains involved in a large outbreak in the second half of 2012 and the Italian strains are the first recorded occurrence of GII.P16_GII.13 in Europe.
Geographical distribution and oncogenic risk association of human papillomavirus type 58 E6 and E7 sequence variations.
2013
Human papillomavirus (HPV) 58 accounts for a notable proportion of cervical cancers in East Asia and parts of Latin America, but it is uncommon elsewhere. The reason for such ethnogeographical predilection is unknown. In our study, nucleotide sequences of E6 and E7 genes of 401 HPV58 isolates collected from 15 countries/cities across four continents were examined. Phylogenetic relationship, geographical distribution and risk association of nucleotide sequence variations were analyzed. We found that the E6 genes of HPV58 variants were more conserved than E7. Thus, E6 is a more appropriate target for type-specific detection, whereas E7 is more appropriate for strain differentiation. The frequ…