Anti-SARS-CoV-2 Spike RBD (Clone 2165) – HRP

Sequenced from human survivors of COVID-19 (SARS-CoV-2)

This recombinant HRP-conjugated antibody is formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.2 - 7.4, 1% BSA. <b> (Warning: Use of sodium azide as a preservative will inhibit the enzyme activity of horseradish peroxidase)</b>

This horseradish peroxidase conjugated monoclonal antibody is stable when stored at 2-8°C. Do not freeze.

Overnight on Blue Ice.

Anti-SARS-CoV-2 Spike RBD-HRP, clone 2165, specifically targets an epitope on the SARS-CoV-2 spike protein receptor-binding domain (RBD).

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is an enveloped, single-stranded, positive-sense RNA virus that belongs to the Coronaviridae family ¹. The SARS-CoV-2 genome, which shares 79.6% identity with SARS-CoV, encodes four essential structural proteins: the spike (S), envelope (E), membrane (M), and nucleocapsid protein (N) ². The S protein is a transmembrane, homotrimeric, class I fusion glycoprotein that mediates viral attachment, fusion, and entry into host cells ³. Each ~180 kDa monomer contains two functional subunits, S1 (~700 a.a) and S2 (~600 a.a), that mediate viral attachment and membrane fusion, respectively. S1 contains two major domains, the N-terminal (NTD) and C-terminal domains (CTD). The CTD contains the receptor-binding domain (RBD), which binds to the angiotensin-converting enzyme 2 (ACE2) receptor on host cells ^3-5. Although both SARS-CoV and SARS-CoV-2 bind the ACE2 receptor, the RBDs only share ~73% amino acid identity, and the SARS-CoV-2 RBD binds with a higher affinity compared to SARS-CoV ^{3, 6}. The RBD is dynamic and undergoes hinge-like conformational changes, referred to as the “down” or “up” conformations, which hide or expose the receptor-binding motifs, respectively ⁷. Following receptor binding, S1 destabilizes, and TMPRSS2 cleaves S2, which undergoes a pre- to post-fusion conformation transition, allowing for membrane fusion ^{8, 9}.

Polyclonal RBD-specific antibodies can block ACE2 binding ^{10, 11}, and anti-RBD neutralizing antibodies are present in the sera of convalescent COVID19 patients ¹², identifying the RBD as an attractive candidate for vaccines and therapeutics. In addition, the RBD is poorly conserved, making it a promising antigen for diagnostic tests ^{13 14}. Serologic tests for the RBD are highly sensitive and specific for detecting SARS-CoV-2 antibodies in COVID19 patients ^{13 15}. Furthermore, the levels of anti-RBD antibodies correlated with SARS-CoV-2 neutralizing antibodies, suggesting the RBD could be used to predict an individual's risk of disease ¹³.

The spike RBD is expressed on the surface of SARS-CoV-2.

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11. Tai, W., He, L., Zhang, X. et al. Cell Mol Immunol 17, 613–620. 2020.
12. Cao Y, Su B, Guo X, et al. Cell. 182(1):73-84.e16. 2020.
13. Premkumar L, Segovia-Chumbez B, Jadi R, et al. medRxiv; 2020.
14. Quinlan BD, Mou H, Zhang L, et al. bioRxiv; 2020.
15. Olba NM, Muller MA, Li W, et al. medRxiv; 2020.