scholarly journals A Potent SARS-CoV-2 Neutralizing Human Monoclonal Antibody That Reduces Viral Burden and Disease Severity in Syrian Hamsters

2020 ◽  
Vol 11 ◽  
Author(s):  
Anna C. Fagre ◽  
John Manhard ◽  
Rachel Adams ◽  
Miles Eckley ◽  
Shijun Zhan ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Disease Severity ◽  
Disease Burden ◽  
Human Monoclonal Antibody ◽  
Receptor Binding Domain ◽  
Yeast Display ◽  
Syrian Hamsters ◽  
Limited Efficacy ◽  
Protein Receptor

The emergence of COVID-19 has led to a pandemic that has caused millions of cases of disease, variable morbidity and hundreds of thousands of deaths. Currently, only remdesivir and dexamethasone have demonstrated limited efficacy, only slightly reducing disease burden, thus novel approaches for clinical management of COVID-19 are needed. We identified a panel of human monoclonal antibody clones from a yeast display library with specificity to the SARS-CoV-2 spike protein receptor binding domain that neutralized the virus in vitro. Administration of the lead antibody clone to Syrian hamsters challenged with SARS-CoV-2 significantly reduced viral load and histopathology score in the lungs. Moreover, the antibody interrupted monocyte infiltration into the lungs, which may have contributed to the reduction of disease severity by limiting immunopathological exacerbation. The use of this antibody could provide an important therapy for treatment of COVID-19 patients.

scholarly journals A potent SARS-CoV-2 neutralizing human monoclonal antibody that reduces viral burden and disease severity in Syrian hamsters

2020 ◽  
Author(s):  
Anna C. Fagre ◽  
John Manhard ◽  
Rachel Adams ◽  
Miles Eckley ◽  
Shijun Zhan ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Disease Severity ◽  
Disease Burden ◽  
Human Monoclonal Antibody ◽  
Receptor Binding Domain ◽  
Yeast Display ◽  
Syrian Hamsters ◽  
Limited Efficacy ◽  
Protein Receptor

AbstractThe emergence of COVID-19 has led to a pandemic that has caused millions of cases of disease, variable morbidity and hundreds of thousands of deaths. Currently, only remdesivir and dexamethasone have demonstrated limited efficacy, only slightly reducing disease burden, thus novel approaches for clinical management of COVID-19 are needed. We identified a panel of human monoclonal antibody clones from a yeast display library with specificity to the SARS-CoV-2 spike protein receptor binding domain that neutralized the virus in vitro. Administration of the lead antibody clone to Syrian hamsters challenged with SARS-CoV-2 significantly reduced viral load and histopathology score in the lungs. Moreover, the antibody interrupted monocyte infiltration into the lungs, which may have contributed to the reduction of disease severity by limiting immunopathological exacerbation. The use of this antibody could provide an important therapy for treatment of COVID-19 patients.

scholarly journals Isolation and comparative analysis of antibodies that broadly neutralize sarbecoviruses

2021 ◽  
Author(s):  
Lihong Liu ◽  
Sho Iketani ◽  
Yicheng Guo ◽  
Ryan Casner ◽  
Eswar Reddem ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Comparative Analysis ◽  
Receptor Binding ◽  
Comparative Studies ◽  
Human Monoclonal Antibody ◽  
Receptor Binding Domain ◽  
Pandemic Preparedness ◽  
Antibody Class

The devastation caused by SARS-CoV-2 has made clear the importance of pandemic preparedness. To address future zoonotic outbreaks due to related viruses in the sarbecovirus subgenus, we identified a human monoclonal antibody, 10-40, that neutralized or bound all sarbecoviruses tested in vitro and protected against SARS-CoV-2 and SARS-CoV in vivo. Comparative studies with other receptor-binding domain (RBD)-directed antibodies showed 10-40 to have the greatest breadth against sarbecoviruses and thus its promise as an agent for pandemic preparedness. Moreover, structural analyses on 10-40 and similar antibodies not only defined an epitope cluster in the inner face of the RBD that is well conserved among sarbecoviruses, but also uncovered a new antibody class with a common CDRH3 motif. Our analyses also suggested that elicitation of this class of antibodies may not be overly difficult, an observation that bodes well for the development of a pan-sarbecovirus vaccine.

scholarly journals A human monoclonal antibody targeting a conserved pocket in the SARS-CoV-2 receptor-binding domain core

2020 ◽  
Author(s):  
Juliette Fedry ◽  
Daniel L. Hurdiss ◽  
Chunyan Wang ◽  
Wentao Li ◽  
Gonzalo Obal ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Receptor Binding ◽  
Human Monoclonal Antibody ◽  
Binding Domain ◽  
Structural Basis ◽  
Binding Motif ◽  
Receptor Binding Domain ◽  
Hamster Model ◽  
Health Crisis

AbstractSARS-CoV-2 has caused a global outbreak of severe respiratory disease (COVID-19), leading to an unprecedented public health crisis. To date, there has been over thirty-three million diagnosed infections, and over one million deaths. No vaccine or targeted therapeutics are currently available. We previously identified a human monoclonal antibody, 47D11, capable of cross-neutralising SARS-CoV-2 and the related 2002/2003 SARS-CoV in vitro, and preventing SARS-CoV-2 induced pneumonia in a hamster model. Here we present the structural basis of its neutralization mechanism. We describe cryo-EM structures of trimeric SARS-CoV and SARS-CoV-2 spike ectodomains in complex with the 47D11 Fab. These data reveal that 47D11 binds specifically to the closed conformation of the receptor binding domain, distal to the ACE2 binding site. The CDRL3 stabilises the N343 glycan in an upright conformation, exposing a conserved and mutationally constrained hydrophobic pocket, into which the CDRH3 loop inserts two aromatic residues. Interestingly, 47D11 preferentially selects for the partially open conformation of the SARS-CoV-2 spike, suggesting that it could be used effectively in combination with other antibodies that target the exposed receptor-binding motif. Taken together, these results expose a cryptic site of vulnerability on the SARS-CoV-2 RBD and provide a structural roadmap for the development of 47D11 as a prophylactic or post-exposure therapy for COVID-19.

scholarly journals Evaluation of Fab and F(ab′)2 Fragments and Isotype Variants of a Recombinant Human Monoclonal Antibody against Shiga Toxin 2

2010 ◽  
Vol 78 (3) ◽  
pp. 1376-1382 ◽  
Author(s):  
Donna E. Akiyoshi ◽  
Abhineet S. Sheoran ◽  
Curtis M. Rich ◽  
L. Richard ◽  
Susan Chapman-Bonofiglio ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Shiga Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Human Monoclonal Antibody ◽  
Chinese Hamster ◽  
The Body ◽  
Neutralization Activity ◽  
Shiga Toxin 2

ABSTRACT 5C12 HuMAb is a human monoclonal antibody against the A subunit of Shiga toxin 2 (Stx2). We have previously shown that 5C12 HuMAb effectively neutralizes the cytotoxic effects of this toxin by redirecting its transport within the cell and also by neutralizing the toxin's ability to inhibit protein synthesis. The 5C12 HuMAb and its recombinant IgG1 version protect mice at a dose of 0.6 μg against a lethal challenge of Stx2. The contribution of the Fc region to this observed neutralization activity of the 5C12 antibody against Stx2 was investigated in this study. Using recombinant DNA technology, 5C12 isotype variants (IgG1, IgG2, IgG3, and IgG4) and antibody fragments [Fab, F(ab′)2] were expressed in Chinese hamster ovary cells and evaluated in vitro and in vivo. All four 5C12 isotype variants showed protection in vitro, with the IgG3 and IgG4 variants showing the highest protection in vivo. The Fab and F(ab′)2 fragments also showed protection in vitro but no protection in the mouse toxicity model. Similar results were obtained for a second HuMAb (5H8) against the B subunit of Stx2. The data suggest the importance of the Fc region for neutralization activity, but it is not clear if this is related to the stability of the full-length antibody or if the Fc region is required for effective elimination of the toxin from the body.

Generation and characterization of a human monoclonal antibody that neutralizes diverse HIV-1 isolates in vitro

AIDS ◽  
1992 ◽  
Vol 6 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Douglas F. Lake ◽  
Takashi Kawamura ◽  
Takami Tomiyama ◽  
W. Edward Robinson ◽  
Yoh-ichi Matsumoto ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Monoclonal Antibody ◽  
Hiv 1

scholarly journals Generation and Activity Evaluation of a Mouse-Human Immunoglobulin G1 Chimeric Antibody to Histoplasma capsulatum HSP60

2021 ◽  
Author(s):  
Ágata Nogueira D'Áurea Moura ◽  
Scott J. Garforth ◽  
Leandro Buffoni Roque da Silva ◽  
Darien Woodley ◽  
Filipe Vieira Barbalho ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Histoplasma Capsulatum ◽  
Physiological Stress ◽  
Human Monoclonal Antibody ◽  
Current Treatment ◽  
Chimeric Antibody ◽  
Human Antibody ◽  
Chimeric Mouse ◽  
Dimorphic Fungi

Heat shock proteins (Hsps) are highly conserved molecules that are constitutively expressed and upregulated in response to physiological stress conditions. These immunogenic chaperones can have essential functions in fungi, particularly in dimorphic pathogens. Histoplasma capsulatum and Paracoccidioides species are dimorphic fungi that are the causative agents of histoplasmosis and paracoccidioidomycosis, respectively, which are systemic mycoses with significant rates of morbidity and mortality. Current treatment consists of long-term antifungal agents, and there is an urgent need for new therapeutic approaches with higher efficacy, lower toxicity, better biodistribution and improved selectivity. We engineered an immunoglobulin G1 (IgG1) isotype chimeric mouse-human monoclonal antibody, titled ch-MAb 4E12, from the parental IgG2a MAb 4E12, a monoclonal antibody to H. capsulatum Hsp60 that is protective in experimental histoplasmosis and paracoccidioidomycosis models elicited by H. capsulatum var. capsulatum and Paracoccidioides lutzii, respectively. The ch-MAb 4E12 increased phagolysosomal fusion and enhanced the yeasts uptake by PMA differentiated human THP1 macrophage cells in vitro. At low concentrations, the chimeric antibody significantly reduced the pulmonary and splenic fungal burden compared to an irrelevant antibody or no treatment. These results are the first to show that a chimeric mouse-human antibody can modify infection caused by dimorphic fungi.

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