scholarly journals The FDA-Approved Drug Nelfinavir Inhibits Lytic Cell-Free but Not Cell-Associated Nonlytic Transmission of Human Adenovirus

2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Fanny Georgi ◽  
Vardan Andriasyan ◽  
Robert Witte ◽  
Luca Murer ◽  
Silvio Hemmi ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Recurrent Disease ◽  
Human Adenovirus ◽  
Aspartyl Protease ◽  
Viral Particles ◽  
Highly Sensitive ◽  
Immunodeficiency Virus ◽  
Nelfinavir Mesylate ◽  
Cell Transmission ◽  
Slow Growing

ABSTRACT Adenoviruses (AdVs) are prevalent and give rise to chronic and recurrent disease. Human AdV (HAdV) species B and C, such as HAdV-C2, -C5, and -B14, cause respiratory disease and constitute a health threat for immunocompromised individuals. HAdV-Cs are well known for lysing cells owing to the E3 CR1-β-encoded adenovirus death protein (ADP). We previously reported a high-throughput image-based screening framework and identified an inhibitor of HAdV-C2 multiround infection, nelfinavir mesylate. Nelfinavir is the active ingredient of Viracept, an FDA-approved inhibitor of human immunodeficiency virus (HIV) aspartyl protease that is used to treat AIDS. It is not effective against single-round HAdV infections. Here, we show that nelfinavir inhibits lytic cell-free transmission of HAdV, indicated by the suppression of comet-shaped infection foci in cell culture. Comet-shaped foci occur upon convection-based transmission of cell-free viral particles from an infected cell to neighboring uninfected cells. HAdV lacking ADP was insensitive to nelfinavir but gave rise to comet-shaped foci, indicating that ADP enhances but is not required for cell lysis. This was supported by the notion that HAdV-B14 and -B14p1 lacking ADP were highly sensitive to nelfinavir, although HAdV-A31, -B3, -B7, -B11, -B16, -B21, -D8, -D30, and -D37 were less sensitive. Conspicuously, nelfinavir uncovered slow-growing round HAdV-C2 foci, independent of neutralizing antibodies in the medium, indicative of nonlytic cell-to-cell transmission. Our study demonstrates the repurposing potential of nelfinavir with postexposure efficacy against different HAdVs and describes an alternative nonlytic cell-to-cell transmission mode of HAdV.

scholarly journals The FDA-approved drug Nelfinavir inhibits lytic cell-free transmission of human adenoviruses

2020 ◽  
Author(s):  
Fanny Georgi ◽  
Vardan Andriasyan ◽  
Robert Witte ◽  
Luca Murer ◽  
Silvio Hemmi ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Recurrent Disease ◽  
Human Immuno Deficiency Virus ◽  
Viral Particles ◽  
Highly Sensitive ◽  
Nelfinavir Mesylate ◽  
Cell Transmission ◽  
Acquired Immunodeficiency ◽  
Immunodeficiency Syndrome ◽  
Slow Growing

AbstractAdenoviruses (AdVs) are prevalent and give rise to chronic and recurrent disease. The human AdV (HAdV) species B and C, such as HAdV-C2, C5 and B14, cause respiratory disease, and constitute a health threat for immuno-compromised individuals. HAdV-Cs are well known for lysing cells, owing to the E3 CR1-β-encoded adenovirus death protein (ADP). We previously reported a high-throughput image-based screening framework and identified an inhibitor of HAdV-C2 multi-round infection, Nelfinavir Mesylate. Nelfinavir is the active ingredient of Viracept, an FDA-approved inhibitor of the human immuno-deficiency virus (HIV) aspartyl protease, and used to treat acquired immunodeficiency syndrome (AIDS). It is not effective against single round HAdV infections. Here, we show that Nelfinavir inhibits the lytic cell-free transmission of HAdV, indicated by the suppression of comet-shaped infection foci in cell culture. Comet-shaped foci occur upon convection-based transmission of cell-free viral particles from an infected cell to neighbouring uninfected cells. HAdV lacking ADP was insensitive to Nelfinavir, but gave rise to comet-shaped foci indicating that ADP enhances but is not required for cell lysis. This was supported by the notion that HAdV-B14 and B14p1 lacking ADP were highly sensitive to Nelfinavir, although HAdV-A31, B3, B7, B11, B16, B21, D8, D30 or D37 were less sensitive. Conspicuously, Nelfinavir uncovered slow-growing round-shaped HAdV-C2 foci, independent of neutralizing antibodies in the medium, indicative of non-lytic cell-to-cell transmission. Our study demonstrates the repurposing potential of Nelfinavir with post-exposure efficacy against different HAdVs, and describes an alternative non-lytic cell-to-cell transmission mode of HAdV.Graphical AbstractFigure 1.

scholarly journals Flow Cytometry Analysis of HIV-1 Env Conformations at the Surface of Infected Cells and Virions: Role of Nef, CD4, and SERINC5

2019 ◽  
Vol 94 (6) ◽  
Author(s):  
Isabelle Staropoli ◽  
Jérémy Dufloo ◽  
Anaïs Ducher ◽  
Pierre-Henri Commere ◽  
Anna Sartori-Rupp ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Cellular Proteins ◽  
Viral Infectivity ◽  
Viral Particles ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Env Protein ◽  
The Impact ◽  
Hiv 1

ABSTRACT The HIV-1 Env protein is exposed at the surface of virions and infected cells. Env fluctuates between different closed and open structural states and these conformations influence both viral infectivity and sensitivity to antibody binding and neutralization. We established a flow virometry assay to visualize Env proteins at the surface of human immunodeficiency virus type 1 (HIV-1) virions. The assay is performed on ultracentrifuged fluorescent viral particles that are stained with a panel of broadly neutralizing antibodies (bNAbs) and nonneutralizing antibodies (nnAbs) that probe different epitopes of Env. We used this assay to compare Env at the surface of producer cells and viral particles and to analyze the effect of Nef, CD4, and SERINC5 on Env accessibility to antibodies. We studied the laboratory-adapted strain NL4-3 and two transmitted/founder viruses, THRO and CH058. We confirm that antibody accessibility varies between viral strains and show that Nef, CD4, and SERINC5 additively impact Env conformations. We further demonstrate that the Env accessibility profile on virions is globally similar to that observed on HIV-1-infected cells, with some noticeable differences. For instance, nnAbs bind to virions more efficiently than to producer cells, likely reflecting changes in Env conformational states on mature viral particles. This test complements other techniques and provides a convenient and simple tool for quantifying and probing the structure of Env at the virion surface and to analyze the impact of viral and cellular proteins on these parameters. IMPORTANCE HIV-1 Env conformation is one of the key parameters determining viral infectivity. The flow virometry-based assay developed in this study allows for the characterization of proteins incorporated in HIV-1 particles. We studied the conformation of HIV-1 Env and the impact that the viral protein Nef and the cellular proteins CD4 and SERINC5 have on Env accessibility to antibodies. Our assay permitted us to highlight some noticeable differences in the conformation of Env between producer cells and viral particles. It contributes to a better understanding of the actual composition of HIV-1 particles.

scholarly journals Impact of maraviroc-resistant and low-CCR5-adapted mutations induced by in vitro passage on sensitivity to anti-envelope neutralizing antibodies

2014 ◽  
Vol 95 (8) ◽  
pp. 1816-1826 ◽  
Author(s):  
Kazuhisa Yoshimura ◽  
Shigeyoshi Harada ◽  
Samatchaya Boonchawalit ◽  
Yoko Kawanami ◽  
Shuzo Matsushita
Keyword(s):  
Neutralizing Antibodies ◽  
Infectious Clone ◽  
Serial Passage ◽  
Autologous Plasma ◽  
Subtype B ◽  
Highly Sensitive ◽  
Immunodeficiency Virus ◽  
Low Sensitivity ◽  
Hiv 1

The aim of this study was to generate maraviroc (MVC)-resistant viruses in vitro using a human immunodeficiency virus type 1 subtype B clinical isolate (HIV-1KP-5) to understand the mechanism(s) of resistance to MVC. To select HIV-1 variants resistant to MVC in vitro, we exposed high-chemokine (C-C motif) receptor 5 (CCR5)-expressing PM1/CCR5 cells to HIV-1KP-5 followed by serial passage in the presence of MVC. We also passaged HIV-1KP-5 in PM1 cells, which were low CCR5 expressing to determine low-CCR5-adapted substitutions and compared the Env sequences of the MVC-selected variants. Following 48 passages with MVC (10 µM), HIV-1KP-5 acquired a resistant phenotype [maximal per cent inhibition (MPI) 24 %], whilst the low-CCR5-adapted variant had low sensitivity to MVC (IC50 ~200 nM), but not reduction of the MPI. The common substitutions observed in both the MVC-selected and low-CCR5-adapted variants were selected from the quasi-species, in V1, V3 and V5. After 14 passages, the MVC-selected variants harboured substitutions around the CCR5 N-terminal-binding site and V3 (V200I, T297I, K305R and M434I). The low-CCR5-adapted infectious clone became sensitive to anti-CD4bs and CD4i mAbs, but not to anti-V3 mAb and autologous plasma IgGs. Conversely, the MVC-selected clone became highly sensitive to the anti-envelope (Env) mAbs tested and the autologous plasma IgGs. These findings suggest that the four MVC-resistant mutations required for entry using MVC-bound CCR5 result in a conformational change of Env that is associated with a phenotype sensitive to anti-Env neutralizing antibodies.

scholarly journals Evaluation of a Pseudovirus Neutralization Assay for SARS-CoV-2 and Correlation with Live Virus-Based Micro Neutralization Assay

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 994
Author(s):  
Ahmed Majdi K. Tolah ◽  
Sayed S. Sohrab ◽  
Khaled Majdi K. Tolah ◽  
Ahmed M. Hassan ◽  
Sherif A. El-Kafrawy ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Epidemiological Studies ◽  
Neutralization Assay ◽  
Serum Samples ◽  
Live Virus ◽  
Spike Gene ◽  
Microneutralization Assay ◽  
Viral Particles ◽  
Reliable Performance ◽  
Prior Infection

The unusual cases of pneumonia outbreak were reported from Wuhan city in late December 2019. Serological testing provides a powerful tool for the identification of prior infection and for epidemiological studies. Pseudotype virus neutralization assays are widely used for many viruses and applications in the fields of serology. The accuracy of pseudotype neutralizing assay allows for its use in low biosafety lab and provides a safe and effective alternative to the use of wild-type viruses. In this study, we evaluated the performance of this assay compared to the standard microneutralization assay as a reference. The lentiviral pseudotype particles were generated harboring the Spike gene of SARS-CoV-2. The generated pseudotype particles assay was used to evaluate the activity of neutralizing antibodies in 300 human serum samples from a COVID-19 sero-epidemiological study. Testing of these samples resulted in 55 positive samples and 245 negative samples by pseudotype viral particles assay while microneutralization assay resulted in 64 positive and 236 negative by MN assay. Compared to the MN, the pseudotyped viral particles assay showed a sensitivity of 85.94% and a specificity of 100%. Based on the data generated from this study, the pseudotype-based neutralization assay showed a reliable performance for the detection of neutralizing antibodies against SARS-CoV-2 and can be used safely and efficiently as a diagnostic tool in a biosafety level 2 laboratory.

scholarly journals Feline immunodeficiency virus (FIV) vaccine efficacy and FIV neutralizing antibodies

Vaccine ◽  
2014 ◽  
Vol 32 (6) ◽  
pp. 746-754 ◽  
Author(s):  
James K. Coleman ◽  
Ruiyu Pu ◽  
Marcus M. Martin ◽  
Ezra N. Noon-Song ◽  
Raphael Zwijnenberg ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Vaccine Efficacy ◽  
Neutralizing Antibodies ◽  
Immunodeficiency Virus

scholarly journals Quintuple Deglycosylation Mutant of Simian Immunodeficiency Virus SIVmac239 in Rhesus Macaques: Robust Primary Replication, Tightly Contained Chronic Infection, and Elicitation of Potent Immunity against the Parental Wild-Type Strain

2001 ◽  
Vol 75 (9) ◽  
pp. 4023-4028 ◽  
Author(s):  
Kazuyasu Mori ◽  
Yasuhiro Yasutomi ◽  
Shinji Ohgimoto ◽  
Tadashi Nakasone ◽  
Shiki Takamura ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Chronic Infection ◽  
Neutralizing Antibodies ◽  
Rhesus Macaques ◽  
Chronic Phase ◽  
Wild Type ◽  
Live Attenuated Vaccine ◽  
Challenge Virus ◽  
Culture Cells ◽  
Immunodeficiency Virus

ABSTRACT We previously generated a mutant of simian immunodeficiency virus (SIV) lacking 5 of a total of 22 N-glycans in its external envelope protein gp120 with no impairment in viral replication capability and infectivity in tissue culture cells. Here, we infected rhesus macaques with this mutant and found that it also replicated robustly in the acute phase but was tightly, though not completely, contained in the chronic phase. Thus, a critical requirement for the N-glycans for the full extent of chronic infection was demonstrated. No evidence indicating reversion to a wild type was obtained during the observation period of more than 40 weeks. Monkeys infected with the mutant were found to tolerate a challenge infection with wild-type SIV very well. Analyses of host responses following challenge revealed no neutralizing antibodies against the challenge virus but strong secondary responses of cytotoxic T lymphocytes against multiple antigens, including Gag-Pol, Nef, and Env. Thus, the quintuple deglycosylation mutant appeared to represent a novel class of SIV live attenuated vaccine.

scholarly journals Consistent Patterns of Change during the Divergence of Human Immunodeficiency Virus Type 1 Envelope from That of the Inoculated Virus in Simian/Human Immunodeficiency Virus-Infected Macaques

2006 ◽  
Vol 80 (2) ◽  
pp. 999-1014 ◽  
Author(s):  
W.M. Blay ◽  
S. Gnanakaran ◽  
B. Foley ◽  
N. A. Doria-Rose ◽  
B. T. Korber ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Disulfide Bonds ◽  
Neutralizing Antibodies ◽  
Outer Region ◽  
Synonymous Substitution ◽  
Cross Sectional Study ◽  
Macaca Nemestrina ◽  
Cross Sectional ◽  
Immunodeficiency Virus ◽  
And Shifts

ABSTRACT We have analyzed changes to proviral Env gp120 sequences and the development of neutralizing antibodies (NAbs) during 1 year of simian/human immunodeficiency virus SHIV-89.6P infection in 11 Macaca nemestrina macaques. Seven macaques had significant env divergence from that of the inoculum, and macaques with greater divergence had higher titers of homologous NAbs. Substitutions in sequons encoding potential N-linked glycosylation sites (PNGs) were among the first to be established, although overall the total number of sequons did not increase significantly. The majority (19 of 23) of PNGs present in the inoculum were conserved in the sequences from all macaques. Statistically significant variations in PNGs occurred in multiple macaques within constrained regions we term “hot spots,” resulting in the selection of sequences more similar to the B consensus. These included additions on V1, the N-terminal side of V4, and the outer region of C2. Complex mutational patterns resulted in convergent PNG shifts in V2 and V5. Charge changes in Env V1V2, resulting in a net acidic charge, and a proline addition in V5 occurred in several macaques. Molecular modeling of the 89.6P sequence showed that the conserved glycans lie on the silent face of Env and that many are proximal to disulfide bonds, while PNG additions and shifts are proximal to the CD4 binding site. Nonsynonymous-to-synonymous substitution ratios suggest that these changes result from selective pressure. This longitudinal and cross-sectional study of mutations in human immunodeficiency virus (HIV) env in the SHIV background provides evidence that there are more constraints on the configuration of the glycan shield than were previously appreciated.

Plaque Formation by Chlamydia in L Cells

1970 ◽  
Vol 1 (3) ◽  
pp. 259-262
Author(s):  
Joyce Banks ◽  
B. Eddie ◽  
Julius Schachter ◽  
K. F. Meyer
Keyword(s):  
Cell Lines ◽  
Plaque Assay ◽  
Mouse Fibroblast ◽  
Plaque Formation ◽  
Fibroblast Cells ◽  
Human Origin ◽  
L Cells ◽  
Highly Sensitive ◽  
Slow Growing ◽  
Potential Tool

Chlamydiae were found capable of producing plaques in several cell lines. Mouse fibroblast cells, L-929, proved the most sensitive to infection and yielded plaques of the highest clarity. Assay of chlamydial infectivity by plaque titration was at least as sensitive as egg ld 50 determination. Among chlamydial isolates of avian, mammalian, and human origin, only slow-growing trachoma-inclusion-conjunctivitis agents did not produce plaques. The plaque assay is highly sensitive, reproducible, and offers a potential tool for investigations requiring accurate measurement of small changes in chlamydial infectivity.

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