scholarly journals Small molecule inhibits respiratory syncytial virus entry and infection by blocking the interaction of the viral fusion protein with the cell membrane

2018 ◽  
Vol 33 (3) ◽  
pp. 4287-4299 ◽  
Author(s):  
Wei Tang ◽  
Manmei Li ◽  
Yujun Liu ◽  
Ning Liang ◽  
Zhu Yang ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Cell Membrane ◽  
Fusion Protein ◽  
Small Molecule ◽  
Virus Entry ◽  
Viral Fusion ◽  
Viral Fusion Protein ◽  
Syncytial Virus

scholarly journals 2620. Respiratory Syncytial Virus Rapid Antigen Detection Test, Can It Be Trusted?

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S912-S912
Author(s):  
Nicole Titze ◽  
Jasjit Singh ◽  
Wendi Gornick
Keyword(s):  
Respiratory Syncytial Virus ◽  
Clinical Decision Making ◽  
Fluorescent Antibody ◽  
Antigen Detection ◽  
Urgent Care ◽  
Viral Fusion ◽  
Rapid Antigen Detection Test ◽  
Viral Fusion Protein ◽  
Test Kit ◽  
Syncytial Virus

Abstract Background Many emergency departments and urgent care settings use the commonly available Respiratory Syncytial Virus Rapid Antigen Detection Test (RSV RADT) to diagnose children with RSV. We noted discordant results between RADT and definitive testing. Our study looked at the positive predictive value (PPV) and the false discovery rate (FDR) of the RSV RADT at our facility. Methods We pro- and retrospectively reviewed all patients with positive RSV RAPD tests from July 1, 2017 through March 31, 2019. The test utilized was the QuickVue® RSV Test Kit (QUIDEL Corp, CA, USA), which detects the viral fusion protein present in RSV. Of the tests performed, we chose patients who had definitive testing with either a direct fluorescent antibody (DFA) or a polymerase chain reaction (PCR). We then calculated the PPV as well as the FDR of the RSV RADT during the total interval period, as well as off-season periods (April 1 through October 31) and in-season periods (November 1 through March 31). Results During the study period there were 1128 RSV RADT tests performed, of which 232 had definitive testing with either DFA or PCR (Figures 1 and 2). We found the overall PPV during the study period was 63.3%. During the off-season 30 positive RSV RADT received definitive testing, of which 6 were positive, which yields a PPV of only 20%. In season, 202 RSV RADT received additional testing with 141 positive for RSV. The PPV was 69.8%. The FDR correlated with 36.7% throughout the entire studied period, 80% during the off-season and 30.2% during in-season. As expected, the PPV was higher during times of higher prevalence (Figure 3). Conclusion Based on our results, utilization of the RSV RADT during time of low prevalence yields a high false detection rate and should therefore be discouraged. The use during times of high prevalence yields only modest results and is unlikely to aid in clinical decision-making. Our results differ from those published by the manufacturer (PPV 84%), and may reflect differences in sample collection in the acute care setting. Disclosures All authors: No reported disclosures.

scholarly journals Respiratory Syncytial Virus-Neutralizing Monoclonal Antibodies Motavizumab and Palivizumab Inhibit Fusion

2010 ◽  
Vol 84 (16) ◽  
pp. 8132-8140 ◽  
Author(s):  
Kelly Huang ◽  
Len Incognito ◽  
Xing Cheng ◽  
Nancy D. Ulbrandt ◽  
Herren Wu
Keyword(s):  
Respiratory Syncytial Virus ◽  
Cell Membrane ◽  
Respiratory Disease ◽  
Cell Fusion ◽  
Conformational Changes ◽  
Viral Fusion ◽  
F Protein ◽  
Virus Attachment ◽  
Target Cell Membrane ◽  
Syncytial Virus

ABSTRACT Respiratory syncytial virus (RSV) is a major cause of virus-induced respiratory disease and hospitalization in infants. Palivizumab, an RSV-neutralizing monoclonal antibody, is used clinically to prevent serious RSV-related respiratory disease in high-risk infants. Motavizumab, an affinity-optimized version of palivizumab, was developed to improve protection against RSV. These antibodies bind RSV F protein, which plays a role in virus attachment and mediates fusion. Determining how these antibodies neutralize RSV is important to help guide development of new antibody drugs against RSV and, potentially, other viruses. This study aims to uncover the mechanism(s) by which palivizumab and motavizumab neutralize RSV. Assays were developed to test the effects of these antibodies at distinct steps during RSV replication. Pretreatment of virus with palivizumab or motavizumab did not inhibit virus attachment or the ability of F protein to interact with the target cell membrane. However, pretreatment of virus with either of these antibodies resulted in the absence of detectable viral transcription. These results show that palivizumab and motavizumab act at a point after F protein initiates interaction with the cell membrane and before virus transcription. Palivizumab and motavizumab also inhibited F protein-mediated cell-to-cell fusion. Therefore, these results strongly suggest that these antibodies block both cell-to-cell and virus-to-cell fusion, since these processes are likely similar. Finally, palivizumab and motavizumab did not reduce viral budding. Based on models developed from numerous studies of viral fusion proteins, our results indicate that these antibodies may prevent conformational changes in F protein required for the fusion process.

Vaccination with prefusion-stabilized respiratory syncytial virus fusion protein induces genetically and antigenically diverse antibody responses

Immunity ◽  
2021 ◽  
Author(s):  
Maryam Mukhamedova ◽  
Daniel Wrapp ◽  
Chen-Hsiang Shen ◽  
Morgan S.A. Gilman ◽  
Tracy J. Ruckwardt ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Fusion Protein ◽  
Antibody Responses ◽  
Virus Fusion ◽  
Syncytial Virus

scholarly journals Membrane Interactions of the Tick-Borne Encephalitis Virus Fusion Protein E at Low pH

2002 ◽  
Vol 76 (8) ◽  
pp. 3784-3790 ◽  
Author(s):  
Karin Stiasny ◽  
Steven L. Allison ◽  
Juliane Schalich ◽  
Franz X. Heinz
Keyword(s):  
Fusion Protein ◽  
Membrane Binding ◽  
Low Ph ◽  
Encephalitis Virus ◽  
Soluble Form ◽  
Viral Fusion ◽  
Sequence Element ◽  
Viral Fusion Protein ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

ABSTRACT Membrane fusion of the flavivirus tick-borne encephalitis virus is triggered by the mildly acidic pH of the endosome and is mediated by envelope protein E, a class II viral fusion protein. The low-pH trigger induces an oligomeric rearrangement in which the subunits of the native E homodimers dissociate and the monomeric subunits then reassociate into homotrimers. Here we provide evidence that membrane binding is mediated by the intermediate monomeric form of E, generated by low-pH-induced dissociation of the dimer. Liposome coflotation experiments revealed that association with target membranes occurred only when liposomes were present at the time of acidification, whereas pretreating virions at low pH in the absence of membranes resulted in the loss of their ability to stably attach to liposomes. With the cleavable cross-linker ethylene glycolbis(succinimidylsuccinate), it was shown that a truncated soluble form of the E protein (sE) could bind to membranes only when the dimers were free to dissociate at low pH, and binding could be blocked by a monoclonal antibody that recognizes the fusion peptide, which is at the distal tip of the E monomer but is buried in the native dimer. Surprisingly, analysis of the membrane-associated sE proteins revealed that they had formed trimers. This was unexpected because this protein lacks a sequence element in the C-terminal stem-anchor region, which was shown to be essential for trimerization in the absence of a target membrane. It can therefore be concluded that the formation of a trimeric form of sE is facilitated by membrane binding. Its stability is apparently maintained by contacts between the ectodomains only and is not dependent on sequence elements in the stem-anchor region as previously assumed.  

Herpes simplex virus glycoprotein B (gB) mutations define structural sites in domain I, the membrane proximal region, and the cytodomain that regulate entry.

2021 ◽  
Author(s):  
Qing Fan ◽  
Richard Longnecker ◽  
Sarah A. Connolly
Keyword(s):  
Cell Fusion ◽  
Virus Entry ◽  
Proximal Region ◽  
Glycoprotein B ◽  
Viral Fusion ◽  
Viral Fusion Protein ◽  
Membrane Proximal Region ◽  
Domain V ◽  
Domain I ◽  
Cell Cell

The viral fusion protein glycoprotein B (gB) is conserved in all herpesviruses and is essential for virus entry. During entry, gB fuses viral and host cell membranes by refolding from a prefusion to a postfusion form. We previously introduced three structure-based mutations (gB-I671A/H681A/F683A) into the domain V arm of the gB ectodomain that resulted in reduced cell-cell fusion. A virus carrying these three mutations (called gB3A) displayed a small plaque phenotype and remarkably delayed entry into cells. To identify mutations that could counteract this phenotype, we serially passaged the gB3A virus and selected for revertant viruses with increased plaque size. Genomic sequencing revealed that the revertant viruses had second-site mutations in gB, including E187A, M742T, and S383F/G645R/V705I/V880G. Using expression constructs encoding these mutations, only gB-V880G was shown to enhance cell-cell fusion. In contrast, all of the revertant viruses showed enhanced entry kinetics, underscoring the fact that cell-cell fusion and virus-cell fusion are different. The results indicate that mutations in three different regions of gB (domain I, the membrane proximal region, and the cytoplasmic tail domain) can counteract the slow entry phenotype of gB3A virus. Mapping these compensatory mutations to prefusion and postfusion structural models suggests sites of intramolecular functional interactions with the gB domain V arm that may contribute to the gB fusion function. Importance The nine human herpesviruses are ubiquitous and cause a range of disease in humans. Glycoprotein B (gB) is an essential viral fusion protein that is conserved in all herpesviruses. During host cell entry, gB mediates virus-cell membrane fusion by undergoing a conformational change. Structural models for the prefusion and postfusion form of gB exist, but the details of how the protein converts from one to the other are unclear. We previously introduced structure-based mutations into gB that inhibited virus entry and fusion. By passaging this entry-deficient virus over time, we selected second-site mutations that partially restore virus entry. The location of these mutations suggest regulatory sites that contribute to fusion and gB refolding during entry. gB is a target of neutralizing antibodies and defining how gB refolds during entry could provide a basis for the development of fusion inhibitors for future research or clinical use.

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