scholarly journals Potent prophylactic and therapeutic efficacy of recombinant human ACE2-Fc against SARS-CoV-2 infection in vivo

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhaoyong Zhang ◽  
Eric Zeng ◽  
Lu Zhang ◽  
Weiming Wang ◽  
Yingkang Jin ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Pharmacokinetic Data ◽  
Histological Changes ◽  
Angiotensin Converting Enzyme 2 ◽  
Antiviral Effects ◽  
Excellent Candidate ◽  
Escape Mutants ◽  
Dose Dependent ◽  
Functional Receptor

AbstractThe current COVID-19 pandemic, caused by SARS-CoV-2, poses a serious public health threat. Effective therapeutic and prophylactic treatments are urgently needed. Angiotensin-converting enzyme 2 (ACE2) is a functional receptor for SARS-CoV-2, which binds to the receptor binding domain (RBD) of SARS-CoV-2 spike protein. Here, we developed recombinant human ACE2-Fc fusion protein (hACE2-Fc) and a hACE2-Fc mutant with reduced catalytic activity. hACE2-Fc and the hACE2-Fc mutant both efficiently blocked entry of SARS-CoV-2, SARS-CoV, and HCoV-NL63 into hACE2-expressing cells and inhibited SARS-CoV-2 S protein-mediated cell–cell fusion. hACE2-Fc also neutralized various SARS-CoV-2 strains with enhanced infectivity including D614G and V367F mutations, as well as the emerging SARS-CoV-2 variants, B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.1 (Kappa), and B.1.617.2 (Delta), demonstrating its potent and broad-spectrum antiviral effects. In addition, hACE2-Fc proteins protected HBE from SARS-CoV-2 infection. Unlike RBD-targeting neutralizing antibodies, hACE2-Fc treatment did not induce the development of escape mutants. Furthermore, both prophylactic and therapeutic hACE2-Fc treatments effectively protected mice from SARS-CoV-2 infection, as determined by reduced viral replication, weight loss, histological changes, and inflammation in the lungs. The protection provided by hACE2 showed obvious dose-dependent efficacy in vivo. Pharmacokinetic data indicated that hACE2-Fc has a relative long half-life in vivo compared to soluble ACE2, which makes it an excellent candidate for prophylaxis and therapy for COVID-19 as well as for SARS-CoV and HCoV-NL63 infections.

scholarly journals Ultrapotent human antibodies protect against SARS-CoV-2 challenge via multiple mechanisms

Science ◽  
2020 ◽  
Vol 370 (6519) ◽  
pp. 950-957 ◽  
Author(s):  
M. Alejandra Tortorici ◽  
Martina Beltramello ◽  
Florian A. Lempp ◽  
Dora Pinto ◽  
Ha V. Dang ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Viral Escape ◽  
Angiotensin Converting Enzyme 2 ◽  
Effector Functions ◽  
Human Antibodies ◽  
Binding Domains ◽  
Isolation And Characterization ◽  
Cryo Electron Microscopy ◽  
Escape Mutants

Efficient therapeutic options are needed to control the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has caused more than 922,000 fatalities as of 13 September 2020. We report the isolation and characterization of two ultrapotent SARS-CoV-2 human neutralizing antibodies (S2E12 and S2M11) that protect hamsters against SARS-CoV-2 challenge. Cryo–electron microscopy structures show that S2E12 and S2M11 competitively block angiotensin-converting enzyme 2 (ACE2) attachment and that S2M11 also locks the spike in a closed conformation by recognition of a quaternary epitope spanning two adjacent receptor-binding domains. Antibody cocktails that include S2M11, S2E12, or the previously identified S309 antibody broadly neutralize a panel of circulating SARS-CoV-2 isolates and activate effector functions. Our results pave the way to implement antibody cocktails for prophylaxis or therapy, circumventing or limiting the emergence of viral escape mutants.

scholarly journals Low-dose in vivo protection and neutralization across SARS-CoV-2 variants by monoclonal antibody combinations

2021 ◽  
Author(s):  
Vincent Dussupt ◽  
Rajeshwer S. Sankhala ◽  
Letzibeth Mendez-Rivera ◽  
Samantha M. Townsley ◽  
Fabian Schmidt ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Low Dose ◽  
Viral Escape ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Viral Inactivation ◽  
Angiotensin Converting Enzyme 2 ◽  
Therapeutic Monoclonal Antibodies ◽  
Potent Protection

AbstractPrevention of viral escape and increased coverage against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern require therapeutic monoclonal antibodies (mAbs) targeting multiple sites of vulnerability on the coronavirus spike glycoprotein. Here we identify several potent neutralizing antibodies directed against either the N-terminal domain (NTD) or the receptor-binding domain (RBD) of the spike protein. Administered in combinations, these mAbs provided low-dose protection against SARS-CoV-2 infection in the K18-human angiotensin-converting enzyme 2 mouse model, using both neutralization and Fc effector antibody functions. The RBD mAb WRAIR-2125, which targets residue F486 through a unique heavy-chain and light-chain pairing, demonstrated potent neutralizing activity against all major SARS-CoV-2 variants of concern. In combination with NTD and other RBD mAbs, WRAIR-2125 also prevented viral escape. These data demonstrate that NTD/RBD mAb combinations confer potent protection, likely leveraging complementary mechanisms of viral inactivation and clearance.

scholarly journals Discovery and Development of Human SARS-CoV-2 Neutralizing Antibodies using an Unbiased Phage Display Library Approach

2020 ◽  
Author(s):  
Xia Cao ◽  
Junki Maruyama ◽  
Heyue Zhou ◽  
Lisa Kerwin ◽  
Rachel Sattler ◽  
...  
Keyword(s):  
Phage Display ◽  
Neutralizing Antibodies ◽  
Phage Display Library ◽  
Antibody Library ◽  
Hamster Model ◽  
Functional Profiling ◽  
Dose Dependent ◽  
Potent Protection

ABSTRACTSARS-CoV-2 neutralizing antibodies represent an important component of the ongoing search for effective treatment of and protection against COVID-19. We report here on the use of a naïve phage display antibody library to identify a panel of fully human SARS-CoV-2 neutralizing antibodies. Following functional profiling in vitro against an early pandemic isolate as well as a recently emerged isolate bearing the D614G Spike mutation, the clinical candidate antibody, STI-1499, and the affinity-engineered variant, STI-2020, were evaluated for in vivo efficacy in the Syrian golden hamster model of COVID-19. Both antibodies demonstrated potent protection against the pathogenic effects of the disease and a dose-dependent reduction of virus load in the lungs, reaching undetectable levels following a single dose of 500 micrograms of STI-2020. These data support continued development of these antibodies as therapeutics against COVID-19 and future use of this approach to address novel emerging pandemic disease threats.

Incorporation of an interferon-β neutralizing antibody assay into routine clinical practice

2011 ◽  
Vol 17 (11) ◽  
pp. 1333-1340 ◽  
Author(s):  
RA Farrell ◽  
M Espasandin ◽  
N Lakdawala ◽  
PI Creeke ◽  
V Worthington ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Luciferase Assay ◽  
Post Injection ◽  
Post Dose ◽  
Therapeutic Decisions ◽  
Dose Dependent Fashion ◽  
Polymerase Chain ◽  
Dose Dependent

Background: Incorporation of routine clinical testing for neutralizing antibodies (NAbs) to interferon (IFN)-β has remained problematic. With increasing treatment choice for patients, routine NAb testing should be incorporated to aid therapeutic decisions. Objective: We sought to improve interpretation of NAb results by combining the luciferase NAb assay (luciferase gene expression assay under control of interferon-stimulated response element) and in-vivo biomarker (myxovirus A protein, MxA) induction in patients with MS. Methods: Blood samples (serum and PAXGene® for RNA) were obtained pre-injection and 12 hours post-injection of IFN-β from 144 subjects. Sera were tested for NAbs using the luciferase assay. MxA expression was quantified by real-time polymerase chain reaction (PCR). Results: 26% of samples were NAb positive (titre > 20 NU). There was no difference in NAb titres in the pre- or post-dose sera ( p = 0.643). MxA expression was inhibited in a dose-dependent fashion in NAb positive samples. Mean MxA level post-IFN-β: NAb negative 2330 (95% CI 1940–2719), NAb 20–99 NU 1533 (95% CI 741–2324), NAb 100–600 NU 832 (186–1478) and NAb > 600 NU 101 (95% CI 0–224). NAb titre and MxA level correlated strongly: MxA pre- (Spearman r = −0.72, p < 0.0001), MxA post- (Spearman r = −0.79, p < 0.0001) and MxA induction (Spearman r = −0.67, p = 0.0004). Conclusion: A single, 12-hour post-injection sample should be used to test for NAbs using the luciferase assay and IFN-β bioactivity (MxA) in the clinical setting.

scholarly journals Bispecific antibody prevents SARS-CoV-2 escape and protects mice from disease

2021 ◽  
Author(s):  
Raoul De Gasparo ◽  
Mattia Pedotti ◽  
Luca Simonelli ◽  
Petr Nickl ◽  
Frauke Muecksch ◽  
...  
Keyword(s):  
Single Molecule ◽  
Lung Inflammation ◽  
Neutralizing Antibodies ◽  
Bispecific Antibody ◽  
Viral Escape ◽  
Cellular Receptor ◽  
Receptor Binding Domain ◽  
Angiotensin Converting Enzyme 2 ◽  
Escape Mutants ◽  
Novel Model

SummaryNeutralizing antibodies targeting the receptor binding domain (RBD) of the SARS-CoV-2 Spike (S) are among the most promising approaches against coronavirus disease 2019 (COVID-19)1,2. We developed a bispecific, IgG1-like molecule based on two antibodies derived from COVID-19 convalescent donors, C121 and C1353. CoV-X2 simultaneously binds two independent sites on the RBD and, unlike its parental antibodies, completely prevents S binding to Angiotensin-Converting Enzyme 2 (ACE2), the virus cellular receptor. Furthermore, CoV-X2 recognizes a broad panel of RBD variants and neutralizes SARS-CoV-2 and the escape mutants generated by the single monoclonals at sub-nanomolar concentrations. In a novel model of SARS-CoV-2 infection with lung inflammation, CoV-X2 protects mice from disease and suppresses viral escape. Thus, simultaneous targeting of non-overlapping RBD epitopes by IgG-like bispecific antibodies is feasible and effective, combining into a single molecule the advantages of antibody cocktails.

Somnogenic effects of rabbit and recombinant human interferons in rabbits

1994 ◽  
Vol 267 (1) ◽  
pp. R53-R61 ◽  
Author(s):  
M. Kimura ◽  
J. A. Majde ◽  
L. A. Toth ◽  
M. R. Opp ◽  
J. M. Krueger
Keyword(s):  
Heat Treatment ◽  
Dependent Manner ◽  
Rapid Eye Movement Sleep ◽  
Ifn Alpha ◽  
Antiviral Effects ◽  
Ifn Therapy ◽  
Species Specific ◽  
Dose Dependent

Interferons (IFNs) are antiviral cytokines that possess several central nervous system activities. IFN therapy is associated with sleepiness, and the IFNs expressed during viral infection may be involved in the excess sleep associated with these infections. Most viruses stimulate the production of both IFN-alpha and IFN-beta. Although large doses of human IFN-alpha 2 are somnogenic in rabbits, the effects of species-specific IFNs on sleep in the rabbit have not been documented. We compared the somnogenic and antiviral effects of IFNs derived from rabbits to the effects of recombinant human (rh) IFN-alpha and IFN-beta. When injected intracerebroventricularly, rhIFN-alpha A/D, rabbit IFN-alpha/beta, and rabbit reference IFN induced non-rapid-eye-movement sleep and fever in a dose-dependent manner. However, the doses of rabbit IFNs required to induce sleep were much lower than those of human IFNs. Heat treatment of both rabbit IFNs and human IFNs greatly reduced their in vitro antiviral effects. The in vivo activities of rabbit IFNs and rhIFN-alpha A/D were significantly attenuated after heat treatment. However, rhIFN-beta retained its sleep-promoting action after heat treatment, suggesting that microbial contaminants were responsible for its somnogenic and pyrogenic activities. We conclude that IFN-alpha is somnogenic.

scholarly journals Different In Vivo Effects of HIV-1 Immunodominant Epitope-Specific Cytotoxic T Lymphocytes on Selection of Escape Mutant Viruses

2010 ◽  
Vol 84 (11) ◽  
pp. 5508-5519 ◽  
Author(s):  
Hirokazu Koizumi ◽  
Masao Hashimoto ◽  
Mamoru Fujiwara ◽  
Hayato Murakoshi ◽  
Takayuki Chikata ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Neutralizing Antibodies ◽  
Escape Mutant ◽  
Escape Mutants ◽  
Hiv 1 ◽  
Selection Of ◽  
Strong Ability

ABSTRACT HIV-1 escape mutants are well known to be selected by immune pressure via HIV-1-specific cytotoxic T lymphocytes (CTLs) and neutralizing antibodies. The ability of the CTLs to suppress HIV-1 replication is assumed to be associated with the selection of escape mutants from the CTLs. Therefore, we first investigated the correlation between the ability of HLA-A*1101-restricted CTLs recognizing immunodominant epitopes in vitro and the selection of escape mutants. The result showed that there was no correlation between the ability of these CTLs to suppress HIV-1 replication in vitro and the appearance of escape mutants. The CTLs that had a strong ability to suppress HIV-1 replication in vitro but failed to select escape mutants expressed a higher level of PD-1 in vivo, whereas those that had a strong ability to suppress HIV-1 replication in vitro and selected escape mutants expressed a low level of PD-1. Ex vivo analysis of these CTLs revealed that the latter CTLs had a significantly stronger ability to recognize the epitope than the former ones. These results suggest that escape mutations are selected by HIV-1-specific CTLs that have a stronger ability to recognize HIV-1 in vivo but not in vitro.

scholarly journals Bactericidal Activity of Increasing Daily and Weekly Doses of Moxifloxacin in Murine Tuberculosis

2002 ◽  
Vol 46 (6) ◽  
pp. 1875-1879 ◽  
Author(s):  
Tetsuyuki Yoshimatsu ◽  
Eric Nuermberger ◽  
Sandeep Tyagi ◽  
Richard Chaisson ◽  
William Bishai ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Pharmacokinetic Profile ◽  
Bactericidal Effect ◽  
In Vivo Studies ◽  
Pharmacokinetic Data ◽  
Time Curve ◽  
Pharmacodynamic Profile ◽  
Days Of Therapy ◽  
Dose Dependent

ABSTRACT Moxifloxacin (MXF) is a new 8-methoxyquinolone with potent activity against Mycobacterium tuberculosis and a half-life of 9 to 12 h in humans. Previous in vivo studies using daily doses of 100 mg/kg of body weight have demonstrated bactericidal activity comparable to that of isoniazid (INH) in a murine model of tuberculosis (TB). Recent pharmacokinetic data suggest that MXF may have been underadministered in these studies and that a 400-mg/kg dose in mice better approximates the area under the concentration-time curve obtained in humans after a 400-mg oral dose. Therefore, the bactericidal activity of MXF in doses up to 400 mg/kg given daily or weekly for 28 days was assessed in mice infected intravenously with 5 × 106 CFU of M. tuberculosis. INH was used as a positive control. After 3 days of daily therapy, the CFU counts from splenic homogenates for mice treated with MXF in doses of 100 to 400 mg/kg/day were lower than those from pretreatment controls. No significant differences in CFU counts were seen when mice receiving INH or MXF at 50 mg/kg/day were compared to pretreatment controls. After 28 days of therapy, dose-dependent reductions in CFU counts in splenic homogenates were seen for daily MXF therapy. The maximum bactericidal effect was seen with daily doses of 400 mg/kg, which resulted in a reduction in CFU counts of 1 log10 greater than that with INH treatment, although the difference was not statistically significant. CFU counts from lung homogenates after 28 days of therapy were significantly lower in all treatment groups than in untreated controls. The weekly administration of MXF in doses ranging from 50 to 400 mg/kg resulted in no significant bactericidal activity. Mice receiving daily MXF doses of 200 and 400 mg/kg/day failed to gain weight and appeared ill after 28 days of therapy, findings suggestive of drug toxicity. In conclusion, MXF has dose-dependent bactericidal activity against M. tuberculosis in the mouse when given in doses up to 400 mg/kg, where its pharmacokinetic profile better approximates that of standard human dosages. Combination regimens which take advantage of the enhanced pharmacodynamic profile of MXF at these doses have the potential to shorten the course of antituberculous therapy or allow more intermittent (i.e., once-weekly) therapy and should be evaluated in the mouse model of TB.

scholarly journals A bifluorescent-based assay for the identification of neutralizing antibodies against SARS-CoV-2 variants of concern in vitro and in vivo

2021 ◽  
Author(s):  
Kevin Chiem ◽  
Desarey Morales Vasquez ◽  
Jesus Silvas ◽  
Jun-Gyu Park ◽  
Michael Piepenbrink ◽  
...  
Keyword(s):  
South African ◽  
Neutralizing Antibodies ◽  
Viral Infections ◽  
Rapid Assessment ◽  
The United States ◽  
Viral Fitness ◽  
Angiotensin Converting Enzyme 2 ◽  
Protection Efficacy

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged at the end of 2019 and has been responsible for the still ongoing coronavirus disease 2019 (COVID-19) pandemic. Prophylactic vaccines have been authorized by the United States (US) Food and Drug Administration (FDA) for the prevention of COVID-19. Identification of SARS-CoV-2 neutralizing antibodies (NAbs) is important to assess vaccine protection efficacy, including their ability to protect against emerging SARS-CoV-2 variants of concern (VoC). Here we report the generation and use of a recombinant (r)SARS-CoV-2 USA/WA1/2020 (WA-1) strain expressing Venus and a rSARS-CoV-2 expressing mCherry and containing mutations K417N, E484K, and N501Y found in the receptor binding domain (RBD) of the spike (S) glycoprotein of the South African (SA) B.1.351 (beta, β) VoC, in bifluorescent-based assays to rapidly and accurately identify human monoclonal antibodies (hMAbs) able to neutralize both viral infections in vitro and in vivo. Importantly, our bifluorescent-based system accurately recapitulated findings observed using individual viruses. Moreover, fluorescent-expressing rSARS-CoV-2 and the parental wild-type (WT) rSARS-CoV-2 WA-1 had similar viral fitness in vitro, as well as similar virulence and pathogenicity in vivo in the K18 human angiotensin converting enzyme 2 (hACE2) transgenic mouse model of SARS-CoV-2 infection. We demonstrate that these new fluorescent-expressing rSARS-CoV-2 can be used in vitro and in vivo to easily identify hMAbs that simultaneously neutralize different SARS-CoV-2 strains, including VoC, for the rapid assessment of vaccine efficacy or the identification of prophylactic and/or therapeutic broadly NAbs for the treatment of SARS-CoV-2 infection.

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