Spike RBD Antibody (1035419) [Unconjugated]

In a functional flow cytometry test, Recombinant SARS-Cov-2 Spike RBD His-tagged protein (10500-CV) binds to HEK293 human embryonic kidney cell line transfected with recombinant human ACE-2 and eGFP. (A) Binding is blocked by 50 µg/mL of Mouse Anti-SARS-Cov-2 Spike RBD Monoclonal Antibody (Catalog # MAB105801) but not by (B) Mouse IgG2A Isotype Control (MAB003). Protein binding was detected with Mouse Anti-His APC-conjugated Monoclonal Antibody (IC050A). Staining was performed using our Staining Membrane-Associated Proteins protocol.

• Reactivity: V
• Applications: B/N
• Clone: 1035419
• Clonality: Monoclonal
• Host: Mouse
• Conjugate: Unconjugated

Spike RBD Antibody (1035419) [Unconjugated] Summary

• Immunogen: Human embryonic kidney cell, HEK293-derived SARS-CoV-2 Spike RBD Protein
  Ala319-Phe541
  Accession # YP_009724390.1
• Specificity: Detects SARS-CoV-2 Spike RBD and SARS-CoV-2 B.1.1.529 S RBD (Omicron Variant) in direct ELISAs.
• Source: N/A
• Isotype: IgG2a
• Clonality: Monoclonal
• Host: Mouse
• Purity Statement: Protein A or G purified from hybridoma culture supernatant

Applications/Dilutions

• Dilutions:
  • Blockade of Receptor-ligand Interaction

Packaging, Storage & Formulations

• Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  12 months from date of receipt, -20 to -70 degreesC as supplied. 1 month, 2 to 8 degreesC under sterile conditions after reconstitution. 6 months, -20 to -70 degreesC under sterile conditions after reconstitution.
• Buffer: Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied either lyophilized or as a 0.2 µm filtered solution in PBS.
• Reconstitution Instructions: Reconstitute at 0.5 mg/mL in sterile PBS.

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Spike RBD Antibody (1035419) [Unconjugated]

• Spike RBD

Background

SARS-CoV-2, which causes the global pandemic coronavirus disease 2019 (Covid-19), belongs to a family of viruses known as coronaviruses that are commonly comprised of four structural proteins: Spike protein(S), Envelope protein (E), Membrane protein (M), and Nucleocapsid protein (N) (1). SARS-CoV-2 Spike Protein (S Protein) is a glycoprotein that mediates membrane fusion and viral entry. The S protein is homotrimeric, with each ~180-kDa monomer consisting of two subunits, S1 and S2 (2). In SARS-CoV-2, as with most coronaviruses, proteolytic cleavage of the S protein into two distinct peptides, S1 and S2 subunits, is required for activation. The S1 subunit is focused on attachment of the protein to the host receptor while the S2 subunit is involved with cell fusion (3-5). Based on structural biology studies, the receptor binding domain (RBD), located in the C-terminal region of S1, can be oriented either in the up/standing or down/lying state (6). The standing state is associated with higher pathogenicity and both SARS-CoV-1 and MERS can access this state due to the flexibility in their respective RBDs. A similar two-state structure and flexibility is found in the SARS-CoV-2 RBD (7). Based on amino acid (aa) sequence homology, the SARS-CoV-2 S1 subunit RBD has 73% identity with the RBD of the SARS-CoV-1 S1 RBD, but only 22% homology with the MERS S1 RBD. The low aa sequence homology is consistent with the finding that SARS and MERS bind different cellular receptors (8). The S Protein of the SARS-CoV-2 virus, like the SARS-CoV-1 counterpart, binds Angiotensin-Converting Enzyme 2 (ACE2), but with much higher affinity and faster binding kinetics (9). Before binding to the ACE2 receptor, structural analysis of the S1 trimer shows that only one of the three RBD domains in the trimeric structure is in the "up" conformation. This is an unstable and transient state that passes between trimeric subunits but is nevertheless an exposed state to be targeted for neutralizing antibody therapy (10). Polyclonal antibodies to the RBD of the SARS-CoV-2 protein have been shown to inhibit interaction with the ACE2 receptor, confirming RBD as an attractive target for vaccinations or antiviral therapy (11). There is also promising work showing that the RBD may be used to detect presence of neutralizing antibodies present in a patient's bloodstream, consistent with developed immunity after exposure to the SARS-CoV-2 virus (12). Lastly, it has been demonstrated the S Protein can invade host cells through the CD147/EMMPRIN receptor and mediate membrane fusion (13, 14).

1. Wu, F. et al. (2020) Nature 579:265.
2. Tortorici, M.A. and D. Veesler (2019). Adv. Virus Res. 105:93.
3. Bosch, B.J. et al. (2003) J. Virol. 77:8801.
4. Belouzard, S. et al. (2009) Proc. Natl. Acad. Sci. 106:5871.
5. Millet, J.K. and G. R. Whittaker (2015) Virus Res. 202:120.
6. Yuan, Y. et al. (2017) Nat. Commun. 8:15092.
7. Walls, A.C. et al. (2010) Cell 180:281.
8. Jiang, S. et al. (2020) Trends. Immunol. https://doi.org/10.1016/j.it.2020.03.007.
9. Ortega, J.T. et al. (2020) EXCLI J. 19:410.
10. Wrapp, D. et al. (2020) Science 367:1260.
11. Tai, W. et al. (2020) Cell. Mol. Immunol. https://doi.org/10.1016/j.it.2020.03.007.
12. Okba, N. M. A. et al. (2020). Emerg. Infect. Dis. https://doi.org/10.3201/eid2607.200841.
13. Wang, X. et al. (2020) https://doi.org/10.1038/s41423-020-0424-9.
14. Wang, K. et al. (2020) bioRxiv https://www.biorxiv.org/content/10.1101/2020.03.14.988345v1.

Limitations

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Primary Antibodies are guaranteed for 1 year from date of receipt.

Bioinformatics

• Uniprot:
  • YP_009724390.1(Llama)