Search results for "viral protein"
showing 10 items of 182 documents
Host Cell Calpains Can Cleave Structural Proteins from the Enterovirus Polyprotein
2019
Enteroviruses are small RNA viruses that cause diseases with various symptoms ranging from mild to severe. Enterovirus proteins are translated as a single polyprotein, which is cleaved by viral proteases to release capsid and nonstructural proteins. Here, we show that also cellular calpains have a potential role in the processing of the enteroviral polyprotein. Using purified calpains 1 and 2 in an in vitro assay, we show that addition of calpains leads to an increase in the release of VP1 and VP3 capsid proteins from P1 of enterovirus B species, detected by western blotting. This was prevented with a calpain inhibitor and was dependent on optimal calcium concentration, especially for calpa…
Quantitative characterization of translational riboregulators using an in vitro transcription–translation system
2018
Riboregulators are short RNA sequences that, upon binding to a ligand, change their secondary structure and influence the expression rate of a downstream gene. They constitute an attractive alternative to transcription factors for building synthetic gene regulatory networks because they can be engineered de novo. However, riboregulators are generally designed in silico and tested in vivo, which provides little quantitative information about their performances, thus hindering the improvement of design algorithms. Here we show that a cell-free transcription-translation (TX-TL) system provides valuable information about the performances of in silico designed riboregulators. We first propose a …
Molecular Characterization of Coxsackievirus B5 Isolates from Sewage, Italy 2016–2017
2019
Hereby, the partial Viral Protein 1 sequences of Coxsackievirus B5 (CV-B5) from sewage samples, collected in Italy from 2016 to 2017, were compared with those available in GenBank from clinical samples. Phylogenetic analysis highlighted: (I) the predominant circulation of CV-B5 genogroup B in Italy, and (II) the presence of two new sub-genogroups.
Exploring the Human-Nipah Virus Protein-Protein Interactome
2017
ABSTRACT Nipah virus is an emerging, highly pathogenic, zoonotic virus of the Paramyxoviridae family. Human transmission occurs by close contact with infected animals, the consumption of contaminated food, or, occasionally, via other infected individuals. Currently, we lack therapeutic or prophylactic treatments for Nipah virus. To develop these agents we must now improve our understanding of the host-virus interactions that underpin a productive infection. This aim led us to perform the present work, in which we identified 101 human-Nipah virus protein-protein interactions (PPIs), most of which (88) are novel. This data set provides a comprehensive view of the host complexes that are manip…
Constrained evolvability of interferon suppression in an RNA virus.
2016
AbstractInnate immunity responses controlled by interferon (IFN) are believed to constitute a major selective pressure shaping viral evolution. Viruses encode a variety of IFN suppressors, but these are often multifunctional proteins that also play essential roles in other steps of the viral infection cycle, possibly limiting their evolvability. Here, we experimentally evolved a vesicular stomatitis virus (VSV) mutant carrying a defect in the matrix protein (M∆51) that abolishes IFN suppression and that has been previously used in the context of oncolytic virotherapy. Serial transfers of this virus in normal, IFN-secreting cells led to a modest recovery of IFN blocking capacity and to weak …
Subdominant CD8 T-Cell Epitopes Account for Protection against Cytomegalovirus Independent of Immunodomination▿ †
2008
ABSTRACTCytomegalovirus (CMV) infection continues to be a complication in recipients of hematopoietic stem cell transplantation (HSCT). Preexisting donor immunity is recognized as a favorable prognostic factor for the reconstitution of protective antiviral immunity mediated primarily by CD8 T cells. Furthermore, adoptive transfer of CMV-specific memory CD8 T (CD8-TM) cells is a therapeutic option for preventing CMV disease in HSCT recipients. Given the different CMV infection histories of donor and recipient, a problem may arise from an antigenic mismatch between the CMV variant that has primed donor immunity and the CMV variant acquired by the recipient. Here, we have used the BALB/c mouse…
Highly protective in vivo function of cytomegalovirus IE1 epitope-specific memory CD8 T cells purified by T-cell receptor-based cell sorting.
2005
ABSTRACTReconstitution of antiviral CD8 T cells is essential for controlling cytomegalovirus (CMV) infection after bone marrow transplantation. Accordingly, polyclonal CD8 T cells derived from BALB/c mice infected with murine CMV protect immunocompromised adoptive transfer recipients against CMV disease. The protective population comprises CD8 T cells with T-cell receptors (TCRs) specific for defined and for as-yet-unknown viral epitopes, as well as a majority of nonprotective cells with unrelated specificities. Defined epitopes include IE1/m123 and m164, which are immunodominant in terms of the magnitude of the CD8 T-cell response, and a panel of subordinate epitopes (m04, m18, M45, M83, a…
LKM-1 autoantibodies recognize a short linear sequence in P450IID6, a cytochrome P-450 monooxygenase.
1991
LKM-1 autoantibodies, which are associated with autoimmune chronic active hepatitis, recognize P450IID6, a cytochrome P-450 monooxygenase. The reactivities of 26 LKM-1 antisera were tested with a panel of deletion mutants of P450IID6 expressed in Escherichia coli. 22 sera recognize a 33-amino acid segment of P450IID6, and 11 of these recognize a shorter segment, DPAQPPRD. PAQPPR is also found in IE175 of herpes simplex virus type 1 (HSV-1). Antibodies for HSV-1 proteins were detected by ELISA in 17 of 20 LKM-1 sera tested. An immobilized, synthetic peptide, DPAQPPRDC, was used to purify LKM-1 antibodies. Affinity purified LKM-1 autoantibodies react on immunoblots with a protein in BHK cells…
Trends for genetic variation of Hepatitis C Virus quasispecies in Human Immunodeficiency virus-1 coinfected patients
2007
Chronic infection by Hepatitis C Virus (HCV) causes liver fibrosis, which is accelerated by unknown mechanisms in patients with HIV-1 coinfection. The evolution of HCV quasispecies in this setting of coinfection is not fully understood. To compare HCV quasispecies between HIV-HCV coinfection and HCV monoinfection, we sequenced 340 HCV clones from the HVR-1 and NS3 regions at two different time points in two groups of treatment-naive patients with HCV-1a infection: (1) HIV-HCV positive (n=6); and (2) HIV negative-HCV positive (n=3). In HCV/HIV coinfection, we found a trend for reduced HCV genetic complexity and diversity, and a trend towards reduced dN/dS ratios in the HVR-1 region, especial…
The effect of recombinant alpha-interferon treatment on serum levels of hepatitis B virus-encoded proteins in man.
1987
The effect of alpha-interferon treatment on serum levels of hepatitis B virus-encoded proteins was analyzed in eight patients with chronic type B hepatitis who participated in a pilot study of interferon therapy. Three individuals became HBsAg-negative, 4 lost HBeAg but remained HBsAg-positive and 1 remained positive for both HBsAg and HBeAg. Initiation of interferon treatment was rapidly followed by reduction or loss of hepatitis B virus DNA in the serum but by little immediate change in hepatitis B virus antigen levels. Changes in hepatitis B virus antigens were usually delayed. Loss of HBsAg from the serum was preceded by the sequential disappearance of pre-S-encoded proteins (pre-S1 and…