REGN-CoV-derived Anti-SARS-CoV-2 RBD monoclonal antibodies

SARS-CoV-2 specific neutralization by Casirivimab & Imdevimab

Specific SARS-CoV-2 Spike-RBD recombinant human IgG1 & mouse IgG2a antibodies

Antibody description

InvivoGen provides a set of recombinant monoclonal antibodies (mAbs) featuring either a human IgG1 or a mouse IgG2a constant region, and the variable region of 'Casirivimab (REGN10933)' or 'Imdevimab (REGN10987'),  two clones originally described as potent  SARS-CoV-2 neutralizing mAbs [1]:

— Anti-CoV2RBD-cas-hIgG1 and Anti-CoV2RBD-cas-mIgG2a (derived from Casirivimab)

— Anti-CoV2RBD-imd-hIgG1 and Anti-CoV2RBD-imd-mIgG2a (derived from Imdevimab)

➔ These antibodies have been functionally validated by ELISA and FACS on SARS-CoV2 Spike variants.

InvivoGen's Anti-CoV2RBD-cas and Anti-CoV2RBD-imd mAbs have been generated by recombinant DNA technology, produced in CHO cells, and purified by affinity chromatography, ensuring lot-to-lot reproducibility. Furthermore, these mAbs have been functionally validated by ELISA (see data below). The absence of bacterial contamination has been confirmed by cellular assays. 

Background

Casirivimab and Imdevimab were generated using both humanized mice and convalescent patients [1]. These mAbs specifically target two distinct and non-overlapping regions of the SARS-CoV-2 S-RBD and potently block its binding to the ACE2 receptor on target cells [1]. 

 More details on Casirivimab and Imdevimab

Applications

• Detecting the presence of SARS-CoV-2 in culture supernatant and/or in serum (ELISA)
• Flow cytometry binding assays 
• Developing neutralizing antibody cocktails against SARS-CoV-2
• Monitoring SARS-CoV-2 variant escape

Quality control

• Functionally validated by ELISA using Spike-RBD proteins derived from SARS-CoV-2 variants and either HRP or Luciferase detection

References

1. Hansen J. et al., 2020. Studies in humanized mice and convalescent humans yield a SARS-CoV-2 antibody cocktail. Science 369:1010-1014.

Figures

SARS-CoV-2 Spike-RBD proteins (3 μg/ml) derived from the Wuhan (A), United Kingdom (U.K.) (B), or South-Africa (S.A.) (C) variants were coated on ELISA plates overnight. A 3-fold serial dilution of Anti-CoV2RBD-imd-IgG2a (red curve), Anti-CoV2RBD-cas-mIgG2a (orange curve), CR3022-derived Anti-Spike-RBD mIgG2a (back curve), of Anti-βGal-mIgG2a antibodies (grey curve) was performed for the capture step. A HRP-labelled Anti-mIgG2a antibody (1/1000 dilution) and the HRP substrate OPD (o-phenylenediamine dihydrochloride) were used for the detection step. Absorbance was read at 490 nm.

Anti-human or Anti-murine IgG F(ab’)2 fragment (2 μg/ml) was coated on an ELISA plate overnight. Anti-CoV2RBD-cas-hIgG1 or -mIgG2a (A), Anti-CoV2RBD-imd-hIgG1 or -mIgG2a (B) along with RBD-Lucia proteins (original and V3; 1 μg/ml) were added and incubated for 2 hours at room temperature. After washing (3x times), binding affinity was assessed by measuring the activity of Lucia luciferase in the supernatant using QUANTI-Luc™. Data are shown as a fold change over no antibody.

Specifications

Specificity: SARS-CoV-2 Spike RBD
Clonality: Monoclonal
Isotypes: hIgG1 or mIgG2a
Source: CHO cells
Formulation: 0.2 μm filtered solution in a sodium phosphate buffer with glycine, saccharose, and stabilizing agents.
Purification: purified by affinity chromatography with protein G (hIgG1) or protein A (mIgG2a)
Quality control:

• The complete sequence of each antibody construct has been verified.
• Antibody binding has been validated by ELISA using Spike-RBD proteins derived from SARS-CoV-2 variants and either HRP or Luciferase detection.
• The absence of bacterial contamination (e.g. lipoproteins and endotoxins) has been confirmed using HEK-Blue™ TLR2 and HEK-Blue™ TLR4 cellular assays.

Contents

Note: Each antibody is sold separately.

Details

Casirivimab and Imdevimab were generated using both humanized mice and convalescent patients [1]. These mAbs specifically target two distinct and non-overlapping regions of the SARS-CoV-2 S-RBD and potently block its binding to the ACE2 receptor on target cells [1]. Treatment using a combination of these mAbs (known as REGEN-COV™ or REGN-COV2) has been authorized under emergency use for COVID-19 outpatients [2-4]. Prophylactic and therapeutic administration of this mAb cocktail almost completely blocks the establishment of virus infection in non-human primates [5] and enhances clearance of the virus in patients whose endogenous immune response has not yet been initiated [2].

Learn more about the SARS-CoV-2 Spike protein.

References

1. Hansen J. et al., 2020. Studies in humanized mice and convalescent humans yield a SARS-CoV-2 antibody cocktail. Science 369:1010-1014.
2. Weinreich D.M. et al., 2021. REGN-COV2, a Neutralizing Antibody Cocktail, in Outpatients with Covid-19. N Engl J Med. 384(3):238-251.
3. https://www.fda.gov/media/145610/download.
4. https://www.ema.europa.eu/en/news/ema-issues-advice-use-regn-cov2-antibody-combination-casirivimab-imdevimab. 
5. Baum A. et al., 2020. REGN-COV2 antibodies prevent and treat SARS-CoV-2 infection in rhesus macaques and hamsters. Science 370:1110-1115.