Nucleoprotein Antibodies for SARS-CoV-2

Figure 1. ELISA binding curve of anti-SARS-CoV-2 (COVID-19) & SARS-CoV Nucleoprotein antibodies CR3018 (Ab01690-23.0) and CR3009(Ab01691-23.0) to SARS-CoV-2 N. Plate coated with SARS-CoV-2 Nucleoproteins (REC31812/REC31851; Native Antigen Company) at a concentration of 5 µg/ml. A 3-fold serial dilution from 10,000 ng/ml was performed using Ab01690-23.0 or Ab01690-23.0. Detection using HRP-labelled anti-rabbit antibody. Rabbit anti-Fluorescein antibody (Ab00102-23.0) used as a control.

After launching the successful anti-COVID-19 & SARS-CoV S glycoprotein antibody clone CR3022, we are pleased to announce two anti-SARS-CoV-2 nucleoprotein (nucleocapsid) antibodies for COVID-19 research and diagnostics. Our recombinant antibody technology allows us to offer these antibodies in various engineered formats – such as human IgG1, IgG3, IgM and IgA; antibody fragments; and species such as rabbit and mouse – for use as serological controls and evaluation of mono- and combination-therapy potential.

• Anti-Covid-19 & SARS-CoV Nucleoprotein [CR3018 (03-018)] (Ab01690)
• Anti-Covid-19 & SARS-CoV Nucleoprotein [CR3009 (03-009)] (Ab01691)

The SARS-CoV-2 nucleocapsid (N) protein plays a crucial role in viral infection through its involvement in RNA package and virus particle release. The N protein is highly expressed during viral infection and is widely used in vaccine development serological assays. It was demonstrated that COVID-19 patients’ sera contain IgG, IgM and IgA antibodies against the N protein, showing that SARS-CoV-2 nucleoprotein is a potent antigen useful for diagnostics purposes (PMID: 32416961). Furthermore, the crystal structure of the RNA-binding N-terminal fragment of the SARS-CoV-2 nucleocapsid protein has been established, which is especially valuable for anti-COVID-19 therapeutics development (PMID: 32363136).

Figure 2. Use as positive control in COVID-19 rapid tests. Recombinant IgG/IgM anti-N clones were used as controls on COVID-19 IgM/IgG Rapid Test CE-IVD (UNCOV-40, Elabscience). The antibodies (from left to right) CR3018 IgG1/ IgM, CR3009 IgG1 / IgM, and negative control, were tested at 50 ug/ml diluted in human normal serum (SIGMA S1-100mL). Bands corresponding to IgG or IgM antibodies can be observed for CR3018 and CR3009, with no signal for the negative control.

Competitive ELISA of both anti-nucleocapsid antibodies suggests that they bind different, non-overlapping epitopes of the N protein of SARS-CoV. Thus, a combination of these two antibodies is suggested for virus capture assays. Clone CR3018 (catalog # Ab01690) binds the amino acid residues between 11-19 of the N protein of SARS-CoV, while clone CR3009 (catalog # Ab01691) binds a non-linear/conformational epitope of the N protein of SARS-CoV, both of which are sufficiently conserved to permit binding of these antibodies to SARS-CoV-2.

Figure 1 shows the binding curve of both antibodies in rabbit IgG format to SARS-CoV-2 nucleoproteins, while Figure 2 shows both antibodies being used as positive controls in COVID-19 rapid diagnostic tests, in human IgG1 and IgM formats. Follow the links below to learn more about all available antibody formats or to place an order. If you are looking for this antibody in a different format, or to obtain an order quote, please contact us.