Advancement in Cellular Topographic and Nanoparticle Capture Imaging by High Resolution Microscopy Incorporating a Freeze-Drying and Gaseous Nitrogen-based Approach.

Scanning electron microscopy (SEM) offers an unparalleled view of the membrane topography of mammalian cells by using a conventional osmium (OsO) and ethanol-based tissue preparation. However, conventional SEM methods limit optimal resolution due to ethanol and lipid interactions and interfere with visualization of fluorescent reporter proteins. Therefore, SEM correlative light and electron microscopy (CLEM) has been hindered by the adverse effects of ethanol and OsO on retention of fluorescence signals.

A Genetic Vaccine Encoding Shared Cancer Neoantigens to Treat Tumors with Microsatellite Instability.

Tumors with microsatellite instability (MSI) are caused by a defective DNA mismatch repair system that leads to the accumulation of mutations within microsatellite regions. Indels in microsatellites of coding genes can result in the synthesis of frameshift peptides (FSP). FSPs are tumor-specific neoantigens shared across patients with MSI.

Reverse immunology: From peptide sequence to tumor-killing human T-cell clones.

Recent advances in next generation sequencing expanded the availability of tumor mutanome data that list the mutations present in cancer cells. Mutated proteins are an interesting source of neoantigens that can be used to specifically target tumor cells in the context of immunotherapy. However, identifying new antigenic peptides from mutated proteins remains challenging.

Adenoviral vaccine targeting multiple neoantigens as strategy to eradicate large tumors combined with checkpoint blockade.

Neoantigens (nAgs) are promising tumor antigens for cancer vaccination with the potential of inducing robust and selective T cell responses. Genetic vaccines based on Adenoviruses derived from non-human Great Apes (GAd) elicit strong and effective T cell-mediated immunity in humans. Here, we investigate for the first time the potency and efficacy of a novel GAd encoding multiple neoantigens.

Author Correction: The interferon-inducible isoform of NCOA7 inhibits endosome-mediated viral entry.

In the version of Supplementary Fig. 5a originally published with this Letter, the authors mistakenly duplicated images of LAMP1 staining in place of CD63 staining; this has now been amended to the correct version shown below.

Production and Purification of Cell Culture Hepatitis C Virus.

Hepatitis C virus (HCV) is a peculiar member of the Flaviviridae family, with features in between an enveloped virus and a human lipoprotein and, consequently, unusual biophysical properties that made its production and purification rather challenging.Here we describe methods to generate HCV stocks in cell culture by electroporating in vitro transcribed viral RNA into permissive cell lines as well as downstream concentration and purification strategies.

The interferon-inducible isoform of NCOA7 inhibits endosome-mediated viral entry.

Interferons (IFNs) mediate cellular defence against viral pathogens by upregulation of IFN-stimulated genes whose products interact with viral components or alter cellular physiology to suppress viral replication. Among the IFN-stimulated genes that can inhibit influenza A virus (IAV) are the myxovirus resistance 1 GTPase and IFN-induced transmembrane protein 3 (refs ). Here, we use ectopic expression and gene knockout to demonstrate that the IFN-inducible 219-amino acid short isoform of human nuclear receptor coactivator 7 (NCOA7) is an inhibitor of IAV as well as other viruses that enter the cell by endocytosis, including hepatitis C virus.

Proteomics of HCV virions reveals an essential role for the nucleoporin Nup98 in virus morphogenesis.

Hepatitis C virus (HCV) is a unique enveloped virus that assembles as a hybrid lipoviral particle by tightly interacting with host lipoproteins. As a result, HCV virions display a characteristic low buoyant density and a deceiving coat, with host-derived apolipoproteins masking viral epitopes. We previously described methods to produce high-titer preparations of HCV particles with tagged envelope glycoproteins that enabled ultrastructural analysis of affinity-purified virions.

Advances in experimental systems to study hepatitis C virus in vitro and in vivo.

Hepatitis C virus (HCV) represents a global health concern affecting over 185 million people worldwide. Chronic HCV infection causes liver fibrosis and cirrhosis and is the leading indication for liver transplantation. Recent advances in the field of direct-acting antiviral drugs (DAAs) promise a cure for HCV in over 90% of cases that will get access to these expensive treatments.

Hepatitis C virus RNA functionally sequesters miR-122.

Hepatitis C virus (HCV) uniquely requires the liver-specific microRNA-122 for replication, yet global effects on endogenous miRNA targets during infection are unexplored. Here, high-throughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (AGO) during HCV infection showed robust AGO binding on the HCV 5'UTR at known and predicted miR-122 sites. On the human transcriptome, we observed reduced AGO binding and functional mRNA de-repression of miR-122 targets during virus infection.

Role of hypervariable region 1 for the interplay of hepatitis C virus with entry factors and lipoproteins.

Unlabelled: Hepatitis C virus (HCV) particles associate with lipoproteins and infect cells by using at least four cell entry factors. These factors include scavenger receptor class B type I (SR-BI), CD81, claudin 1 (CLDN1), and occludin (OCLN). Little is known about specific functions of individual host factors during HCV cell entry and viral domains that mediate interactions with these factors.

Successful anti-scavenger receptor class B type I (SR-BI) monoclonal antibody therapy in humanized mice after challenge with HCV variants with in vitro resistance to SR-BI-targeting agents.

Unlabelled: Hepatitis C virus (HCV)-induced endstage liver disease is currently a major indication for liver transplantation. After transplantation the donor liver inevitably becomes infected with the circulating virus. Monoclonal antibodies (mAbs) against the HCV coreceptor scavenger receptor class B type I (SR-BI) inhibit HCV infection of different genotypes, both in cell culture and in humanized mice.

Completion of the entire hepatitis C virus life cycle in genetically humanized mice.

More than 130 million people worldwide chronically infected with hepatitis C virus (HCV) are at risk of developing severe liver disease. Antiviral treatments are only partially effective against HCV infection, and a vaccine is not available. Development of more efficient therapies has been hampered by the lack of a small animal model.

Different requirements for scavenger receptor class B type I in hepatitis C virus cell-free versus cell-to-cell transmission.

Hepatitis C virus (HCV) is believed to initially infect the liver through the basolateral side of hepatocytes, where it engages attachment factors and the coreceptors CD81 and scavenger receptor class B type I (SR-BI). Active transport toward the apical side brings the virus in close proximity of additional entry factors, the tight junction molecules claudin-1 and occludin. HCV is also thought to propagate via cell-to-cell spread, which allows highly efficient virion delivery to neighboring cells.

Ultrastructural analysis of hepatitis C virus particles.

Hepatitis C virus (HCV) is a major cause of chronic liver disease, with an estimated 170 million people infected worldwide. Low yields, poor stability, and inefficient binding to conventional EM grids have posed significant challenges to the purification and structural analysis of HCV. In this report, we generated an infectious HCV genome with an affinity tag fused to the E2 envelope glycoprotein.

Expression of paramyxovirus V proteins promotes replication and spread of hepatitis C virus in cultures of primary human fetal liver cells.

Unlabelled: Here we demonstrate that primary cultures of human fetal liver cells (HFLC) reliably support infection with laboratory strains of hepatitis C virus (HCV), although levels of virus replication vary significantly between different donor cell preparations and frequently decline in a manner suggestive of active viral clearance. To investigate possible contributions of the interferon (IFN) system to control HCV infection in HFLC, we exploited the well-characterized ability of paramyxovirus (PMV) V proteins to counteract both IFN induction and antiviral signaling. The V proteins of measles virus (MV) and parainfluenza virus 5 (PIV5) were introduced into HFLC using lentiviral vectors encoding a fluorescent reporter for visualization of HCV-infected cells.

A human monoclonal antibody targeting scavenger receptor class B type I precludes hepatitis C virus infection and viral spread in vitro and in vivo.

Unlabelled: Endstage liver disease caused by chronic hepatitis C virus (HCV) infection is the leading indication for liver transplantation in the Western world. However, immediate reinfection of the grafted donor liver by circulating virus is inevitable and liver disease progresses much faster than the original disease. Standard antiviral therapy is not well tolerated and usually ineffective in liver transplant patients, whereas anti-HCV immunotherapy is hampered by the extreme genetic diversity of the virus and its ability to spread by way of cell-cell contacts.

A genetically humanized mouse model for hepatitis C virus infection.

Hepatitis C virus (HCV) remains a major medical problem. Antiviral treatment is only partially effective and a vaccine does not exist. Development of more effective therapies has been hampered by the lack of a suitable small animal model.

Real-time imaging of hepatitis C virus infection using a fluorescent cell-based reporter system.

Hepatitis C virus (HCV), which infects 2-3% of the world population, is a causative agent of chronic hepatitis and the leading indication for liver transplantation. The ability to propagate HCV in cell culture (HCVcc) is a relatively recent breakthrough and a key tool in the quest for specific antiviral therapeutics. Monitoring HCV infection in culture generally involves bulk population assays, use of genetically modified viruses and/or terminal processing of potentially precious samples.

Role of scavenger receptor class B type I in hepatitis C virus entry: kinetics and molecular determinants.

Scavenger receptor class B type I (SR-BI) is an essential receptor for hepatitis C virus (HCV) and a cell surface high-density-lipoprotein (HDL) receptor. The mechanism of SR-BI-mediated HCV entry, however, is not clearly understood, and the specific protein determinants required for the recognition of the virus envelope are not known. HCV infection is strictly linked to lipoprotein metabolism, and HCV virions may initially interact with SR-BI through associated lipoproteins before subsequent direct interactions of the viral glycoproteins with SR-BI occur.

High-avidity monoclonal antibodies against the human scavenger class B type I receptor efficiently block hepatitis C virus infection in the presence of high-density lipoprotein.

The human scavenger class B type 1 receptor (SR-B1/Cla1) was identified as a putative receptor for hepatitis C virus (HCV) because it binds to soluble recombinant HCV envelope glycoprotein E2 (sE2). High-density lipoprotein (HDL), a natural SR-B1 ligand, was shown to increase the in vitro infectivity of retroviral pseudoparticles bearing HCV envelope glycoproteins and of cell culture-derived HCV (HCVcc), suggesting that SR-B1 promotes viral entry in an HDL-dependent manner. To determine whether SR-B1 participates directly in HCV infection or facilitates HCV entry through lipoprotein uptake, we generated a panel of monoclonal antibodies (MAbs) against native human SR-B1.

AROS-29 is involved in adaptive response to oxidative stress.

Transient adaptation to mild oxidative stress was induced in human osteosarcoma cells chronically grown in sub-toxic concentrations of diethylmaleate (DEM), a glutathione (GSH) depleting agent. The adapted cells, compared to untreated cells, contain increased concentrations of GSH (4-6 fold) which, upon DEM withdrawal from the culture medium, return to normal values and are more resistant to subsequent oxidizing stress induced either by toxic concentrations of the same agent or by (H(2)O(2)) treatment. To investigate the molecular mechanisms involved in the adaptive response to oxidative stress, we analyzed the gene expression profiles of DEM-adapted cells by differential display.