scholarly journals Recombinant SARS-CoV-2 spike S1-Fc fusion protein induced high levels of neutralizing responses in nonhuman primates

2020 ◽  
Author(s):  
Wenlin Ren ◽  
Hunter Sun ◽  
George F. Gao ◽  
Jianxin Chen ◽  
Sean Sun ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Vaccine Development ◽  
Neutralization Assay ◽  
List Type ◽  
Potential Candidate ◽  
Live Virus ◽  
Global Pandemic ◽  
Fc Fusion Protein ◽  
Antibody Titers ◽  
Strong Candidate

AbstractThe COVID-19 outbreak has become a global pandemic responsible for over 2,000,000 confirmed cases and over 126,000 deaths worldwide. In this study, we examined the immunogenicity of CHO-expressed recombinant SARS-CoV-2 S1-Fc fusion protein in mice, rabbits, and monkeys as a potential candidate for a COVID-19 vaccine. We demonstrate that the S1-Fc fusion protein is extremely immunogenic, as evidenced by strong antibody titers observed by day 7. Strong virus neutralizing activity was observed on day 14 in rabbits immunized with the S1-Fc fusion protein using a pseudovirus neutralization assay. Most importantly, in less than 20 days and three injections of the S1-Fc fusion protein, two monkeys developed higher virus neutralizing titers than a recovered COVID-19 patient in a live SARS-CoV-2 infection assay. Our data strongly suggests that the CHO-expressed SARS-CoV-2 S1-Fc recombinant protein could be a strong candidate for vaccine development against COVID-19.HighlightsCHO-expressed S1-Fc protein is very immunogenic in various animals and can rapidly induce strong antibody productionS1-Fc protein solicits strong neutralizing activities against live virusStable CHO cell line expressing 50 mg/L of S1-Fc and a 3,000 L Bioreactor can produce 3 million doses of human COVID-19 vaccine every 10 days, making it an accessible and affordable option for worldwide vaccination

scholarly journals Serology in Children with Multisystem Inflammatory Syndrome (MIS-C) associated with COVID-19

2020 ◽  
Author(s):  
Christina A. Rostad ◽  
Ann Chahroudi ◽  
Grace Mantus ◽  
Stacey A. Lapp ◽  
Mehgan Teherani ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Limit Of Detection ◽  
Geometric Mean ◽  
Neutralization Assay ◽  
Adverse Outcomes ◽  
Igg Antibody ◽  
Live Virus ◽  
Lengths Of Stay ◽  
Antibody Titers ◽  
Inflammatory Syndrome

Objectives: We aimed to measure SARS-CoV-2 serologic responses in children hospitalized with multisystem inflammatory syndrome (MIS-C) compared to COVID-19, Kawasaki Disease (KD) and other hospitalized pediatric controls. Methods: From March 17, 2020 - May 26, 2020, we prospectively identified hospitalized children at Children's Healthcare of Atlanta with MIS-C (n=10), symptomatic PCR-confirmed COVID-19 (n=10), KD (n=5), and hospitalized controls (n=4). With IRB approval, we obtained prospective and residual blood samples from these children and measured SARS-CoV-2 spike (S) receptor binding domain (RBD) IgM and IgG binding antibodies by quantitative ELISA and SARS-CoV-2 neutralizing antibodies by live-virus focus reduction neutralization assay. We statistically compared the log-transformed antibody titers among groups and performed correlation analyses using linear regression. Results: All children with MIS-C had high titers of SARS-CoV-2 RBD IgG antibodies, which correlated strongly with neutralizing antibodies (R2=0.667, P<0.001). Children with MIS-C had significantly higher SARS-CoV-2 RBD IgG antibody titers (geometric mean titer [GMT] 6800, 95%CI 3495-13231) than children with COVID-19 (GMT 626, 95%CI 251-1563, P<0.001), children with KD (GMT 124, 95%CI 91-170, P<0.001) and other hospitalized pediatric controls (GMT 85 [all below assay limit of detection], P<0.001). All children with MIS-C also had detectable RBD IgM antibodies, indicating recent SARS-CoV-2 infection. RBD IgG titers correlated with erythrocyte sedimentation rate (ESR) (R2=0.512, P<0.046) and with hospital and ICU lengths of stay (R2=0.590, P=0.010). Conclusion: Quantitative SARS-CoV-2 RBD antibody titers may have a role in establishing the diagnosis of MIS-C, distinguishing it from other similar clinical entities, and stratifying risk for adverse outcomes.

scholarly journals A potent bispecific nanobody protects hACE2 mice against SARS-CoV-2 infection via intranasal administration

2021 ◽  
Author(s):  
Xilin Wu ◽  
Lin Cheng ◽  
Ming Fu ◽  
Bilian Huang ◽  
Linjing Zhu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Intranasal Administration ◽  
List Type ◽  
Potential Candidate ◽  
Intranasal Delivery ◽  
Wild Type ◽  
Viral Inhibition ◽  
Live Virus

AbstractThe dramatically expanding COVID-19 needs multiple effective countermeasures. Neutralizing antibodies are a potential therapeutic strategy for treating COVID-19. A number of neutralizing nanobodies (Nbs) were reported for their in vitro activities. However, in vivo protection of these nanobodies was not reported in animal models. In the current report, we characterized several RBD-specific Nbs isolated from a screen of an Nb library derived from an alpaca immunized with SARS-CoV-2 spike glycoprotein (S); among them, three Nbs exhibited picomolar potency against SARS-CoV-2 live virus, pseudotyped viruses, and 15 circulating SARS-CoV-2 variants. To improve the efficacy, various configurations of Nbs were engineered. Nb15-NbH-Nb15, a novel trimer constituted of three Nbs, was constructed to be bispecific for human serum albumin (HSA) and RBD of SARS-CoV-2. Nb15-NbH-Nb15 exhibited sub-ng/ml neutralization potency against the wild-type and currently circulating variants of SARS-CoV-2 with a long half-life in vivo. In addition, we showed that intranasal administration of Nb15-NbH-Nb15 provided 100% protection for both prophylactic and therapeutic purposes against SARS-CoV-2 infection in transgenic hACE2 mice. Nb15-NbH-Nb15 is a potential candidate for both prevention and treatment of SARS-CoV-2 through respiratory administration.One sentence summaryNb15-NbH-Nb15, with a novel heterotrimeric bispecific configuration, exhibited potent and broad neutralization potency against SARS-CoV-2 in vitro and provided in vivo protection against SARS-CoV-2 infection in hACE2 transgenic mice via intranasal delivery.Graphical abstract:HighlightsWe described a novel heterotrimeric configuration of Nb-NbH-Nb (Nb15-NbH-Nb15) that exhibited improved viral inhibition and stability.Nb15-NbH-Nb15 provides ultrahigh neutralization potency against SARS-CoV-2 wild type and 18 mutant variants, including the current circulating variants of D614G and N501Y predominantly in the UK and South Africa.It is the first to demonstrate the Nbs efficacy in preventing and treating SARS-CoV-2 infection in hACE2 transgenic mice via intranasal delivery.

scholarly journals The Optimal Concentration of Formaldehyde is Key to Stabilizing the Pre-Fusion Conformation of Respiratory Syncytial Virus Fusion Protein

Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 628 ◽  
Author(s):  
Wei Zhang ◽  
Lu-Jing Zhang ◽  
Lu-Ting Zhan ◽  
Min Zhao ◽  
Guang-Hua Wu ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Fusion Protein ◽  
Neutralizing Antibody ◽  
Neutralization Assay ◽  
Mean Value ◽  
Optimal Concentration ◽  
F Protein ◽  
Rsv Infection ◽  
Antibody Titers ◽  
Syncytial Virus

Background: To date, there is no licensed vaccine available to prevent respiratory syncytial virus (RSV) infection. The valuable pre-fusion conformation of the fusion protein (pre-F) is prone to lose high neutralizing antigenic sites. The goals of this study were to stabilize pre-F protein by fixatives and try to find the possibility of developing an inactivated RSV vaccine. Methods: The screen of the optimal fixative condition was performed with flow cytometry. BALB/c mice were immunized intramuscularly with different immunogens. The serum neutralizing antibody titers of immunized mice were determined by neutralization assay. The protection and safety of these immunogens were assessed. Results: Fixation in an optimal concentration of formaldehyde (0.0244%–0.0977%) or paraformaldehyde (0.0625%–1%) was able to stabilize pre-F. Additionally, BALB/c mice inoculated with optimally stabilized pre-F protein (opti-fixed) induced a higher anti-RSV neutralization (9.7 log2, mean value of dilution rate) than those inoculated with unstable (unfixed, 8.91 log2, p < 0.01) or excessively fixed (exce-fixed, 7.28 log2, p < 0.01) pre-F protein. Furthermore, the opti-fixed immunogen did not induce enhanced RSV disease. Conclusions: Only the proper concentration of fixatives could stabilize pre-F and the optimal formaldehyde condition provides a potential reference for development of an inactivated RSV vaccine.

scholarly journals Development of highly potent neutralising nanobodies against multiple SARS-CoV-2 variants including the variant of concern B.1.351

2021 ◽  
Author(s):  
Agnieszka M Sziemel ◽  
Shi-Hsia Hwa ◽  
Alex Sigal ◽  
Grace Tyson ◽  
Nicola Logan ◽  
...  
Keyword(s):  
South Africa ◽  
Severe Acute Respiratory Syndrome ◽  
Effective Treatment ◽  
Vaccine Efficacy ◽  
Global Economy ◽  
Vaccine Development ◽  
Modern Medicine ◽  
Economic Damage ◽  
Live Virus ◽  
Global Pandemic

The pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. During the years of 2020-2021, millions of humans have died due to SARS-CoV-2 infection and severe economic damage to the global economy has occurred. Unprecedented rapid investments in vaccine development have been made to counter the spread of SARS-CoV-2 among humans. While vaccines are a key pillar of modern medicine, SARS-CoV-2 has mutated as it spread among humans. Vaccines previously developed and approved by regulators are becoming less effective against new variants. One variant of SARS-CoV-2 known as B.1.351 that was first reported to be present in South Africa significantly reduces the efficacy of vaccines developed to date. Therapeutic options that work against the B.1.351 variant are therefore urgently needed to counteract reduced vaccine efficacy. We present here the discovery of recombinant alpaca antibodies that neutralise live virus of B.1.351 and other SARS-CoV-2 variants potently. The antibodies described here may be a useful tool for clinicians who are treating patients infected with B.1.351 and other SARS-CoV-2 for which there is currently no known highly effective treatment.

scholarly journals Serum Immunoglobulin A Cross-Strain Blockade of Human Noroviruses

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Lisa C. Lindesmith ◽  
Martina Beltramello ◽  
Jesica Swanstrom ◽  
Taylor A. Jones ◽  
Davide Corti ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Vaccine Development ◽  
Immunoglobulin A ◽  
Neutralization Assay ◽  
Viral Gastroenteritis ◽  
Human Noroviruses ◽  
Serum Iga ◽  
Multiple Virus ◽  
Antibody Titers ◽  
Carbohydrate Ligands

Abstract Background.  Human noroviruses are the leading cause of acute viral gastroenteritis, justifying vaccine development despite a limited understanding of strain immunity. After genogroup I (GI).1 norovirus infection and immunization, blockade antibody titers to multiple virus-like particles (VLPs) increase, suggesting that GI cross-protection may occur. Methods.  Immunoglobulin (Ig)A was purified from sera collected from GI.1-infected participants, and potential neutralization activity was measured using a surrogate neutralization assay based on antibody blockade of ligand binding. Human and mouse monoclonal antibodies (mAbs) were produced to multiple GI VLPs to characterize GI epitopes. Results.  Immunoglobulin A purified from day 14 post-GI.1 challenge sera blocked binding of GI.1, GI.3, and GI.4 to carbohydrate ligands. In some subjects, purified IgA preferentially blocked binding of other GI VLPs compared with GI.1, supporting observations that the immune response to GI.1 infection may be influenced by pre-exposure history. For other subjects, IgA equivalently blocked multiple GI VLPs. Only strain-specific mAbs recognized blockade epitopes, whereas strain cross-reactive mAbs recognized nonblockade epitopes. Conclusions.  These studies are the first to describe a functional role for serum IgA in norovirus immunity and the first to characterize human monoclonal antibodies to GI strains, expanding our understanding of norovirus immunobiology.

scholarly journals Anti-Tumor Activity and Pharmacokinetics of AP25-Fc Fusion Protein

2019 ◽  
Vol 16 (7) ◽  
pp. 1032-1041
Author(s):  
Dening Pei ◽  
Jialiang Hu ◽  
Chunming Rao ◽  
Pengcheng Yu ◽  
Hanmei Xu ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Fc Fusion Protein ◽  
Anti Tumor Activity

scholarly journals Systemic administration of monovalent follistatin-like 3-Fc-fusion protein increases muscle mass in mice

iScience ◽  
2021 ◽  
pp. 102488
Author(s):  
Takayuki Ozawa ◽  
Masato Morikawa ◽  
Yasuyuki Morishita ◽  
Kazuki Ogikubo ◽  
Fumiko Itoh ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Muscle Mass ◽  
Systemic Administration ◽  
Fc Fusion Protein

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.

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