Detects SARS-CoV-2 Spike S1 subunit in direct ELISAs and Western blots. Detects SARS-CoV-2 B.1.1.529 S RBD (Omicron Variant) in direct ELISAs. No cross-reactivity with SARS-CoV-2 Spike RBD is observed in direct ELISAs or Western blots.

Clonality

Monoclonal

Host

Mouse

Isotype

IgG₁

Scientific Data Images for SARS-CoV-2 Spike S1 Subunit Antibody

Detection of SARS-CoV-2 Spike S1 by Western Blot.

Western blot shows lysates of recombinant SARS-CoV-2 Spike S1 Subunit and recombinant SARS-CoV-2 Spike RBD. PVDF membrane was probed with 2 µg/mL of Mouse Anti-SARS-CoV-2 Spike S1 Monoclonal Antibody (Catalog # MAB105403) followed by HRP-conjugated Anti-Mouse IgG Secondary Antibody (HAF018). A specific band was detected for Spike S1 at approximately 90 kDa (as indicated). This experiment was conducted under reducing conditions and using Western Blot Buffer Group 1.

Detection of SARS-CoV-2 Spike S1 protein bound to ACE-2 in live HEK293 Human Cell Line Transfected with Human ACE-2 and eGFP by Flow Cytometry.

HEK293 human embryonic kidney cell line transfected with human ACE-2 and eGFP was incubated with Recombinant SARS-CoV-2 Spike S1 Subunit His-Tag protein (10522-CV), then stained with (A) Mouse Anti-SARS-CoV-2 Spike S1 Monoclonal Antibody (Catalog # MAB105403) or (B) Mouse IgG1 Isotype Control Antibody (MAB002) followed by Allophycocyanin-conjugated Anti-Mouse IgG Secondary Antibody (F0101B). Staining was performed using our Staining Membrane-associated Proteins protocol.

Detection of SARS-CoV-2 Spike S1 protein bound to ACE-2 in fixed HEK293 Human Cell Line Transfected with Human ACE-2 and eGFP by Flow Cytometry.

HEK293 human embryonic kidney cell line transfected with human ACE-2 and eGFP was incubated with Recombinant SARS-CoV-2 Spike S1 Subunit His-Tag protein (10522-CV), then stained with (A) Mouse Anti-SARS-CoV-2 Spike S1 Monoclonal Antibody (Catalog # MAB105403) or (B) Mouse IgG1 Isotype Control Antibody (MAB002) followed by Allophycocyanin-conjugated Anti-Mouse IgG Secondary Antibody (F0101B). Prior to staining, cells were fixed with Flow Cytometry Fixation Buffer (FC004). Staining was performed using our Staining Membrane-associated Proteins protocol.

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Applications for SARS-CoV-2 Spike S1 Subunit Antibody

Application

Recommended Usage

CyTOF-ready

Ready to be labeled using established conjugation methods. No BSA or other carrier proteins that could interfere with conjugation.

Flow Cytometry

0.25 µg/10⁶ cells
Sample: SARS-CoV-2 Spike S1 protein bound to ACE-2 in live or fixed HEK293 Human Cell Line Transfected with Human ACE-2 and eGFP

Immunohistochemistry

5-25 µg/mL
Sample: Immersion fixed paraffin-embedded sections of SARS-CoV-2 infected human lung tissue and Human lung infected with SARS delta variant.

Western Blot

2 µg/mL
Sample: Recombinant SARS-CoV-2 Spike S1

Reviewed Applications

Read 1 review rated 5 using MAB105403 in the following applications:

Immunocytochemistry/Immunofluorescence (1 Review)

Formulation, Preparation, and Storage

Purification

Protein A or G purified from hybridoma culture supernatant

Reconstitution

Reconstitute at 0.5 mg/mL in sterile PBS. For liquid material, refer to CoA for concentration.

Formulation

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.

Shipping

Lyophilized product is shipped at ambient temperature. Liquid small pack size (-SP) is shipped with polar packs. Upon receipt, store immediately at the temperature recommended below.

Stability & Storage

Use a manual defrost freezer and avoid repeated freeze-thaw cycles.

12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.

Background: Spike S1 Subunit

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 has 65% identity with SARS-CoV-1 S1 subunit, but only 22% homology with the MERS S1 subunit. 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 S1 subunit 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).

References

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

Long Name

Spike Protein, S1 Subunit

Alternate Names

SARS-CoV-2

UniProt

YP_009724390.1

Additional Spike S1 Subunit Products

Product Documents for SARS-CoV-2 Spike S1 Subunit Antibody

Product Datasheets

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COA

SDS

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Product Specific Notices for SARS-CoV-2 Spike S1 Subunit Antibody

For research use only

Citations
Reviews

Calculators
Flow Cytometry

SARS-CoV-2 Spike S1 Subunit Antibody

R&D Systems, part of Bio-Techne | Catalog # MAB105403

Key Product Details

Species Reactivity

Validated:

Cited:

Applications