​​​​​​​​Access to high quality, well-characterized protein reagents for COVID vaccine research is a fundamental need. Therefore, the Veesler Lab and the Institute for Protein Design​ at the ​University of Washington have produced GLP lots of the following reagents and are pleased provide purified protein to GH-VAP members free of charge in support of their research. They are provided with a Certificate of Testing. Plasmids encoding the antigen ​constructs are available through NIAID's BEI Resources Repository courtesy of the Veesler Lab, and UW is working towards making protein available through BEI as well.

Human ACE-2 receptor  (View the Certificate of Testing and current lot information)
hACE2-Fc​ is a human Fc fusion of the ectodomain of the angiotensin-converting enzyme 2 (ACE2) protein, the human protein on the surface of epithelial cells that SARS CoV and SARS-CoV-2 use to enter cells. Please find a paper reporting a structure of hACE2 to SARS-CoV-2 S here​. hACE2-Fc can be used, for example, in binding assays to confirm that SARS-CoV-2 antigens are properly folded, or as a competitor in serological assays. This protein was expressed using transient transfection in Expi293F cells, purified using protein A affinity chromatography, and characterized by SEC-HPLC, SDS-PAGE, and UV-Vis, with confirmation of binding and Kd assessment by BLI (Octet).

Monoclonal antibody CR3022 (View the Certificate of Testing and current lot information)​
CR3022 is an anti-SARS CoV S mAb that was published in 2006. It has been found to cross-react with SARS-CoV-2 S (both full-length ectodomain and isolated RBD), although it does not neutralize the virus. The binding epitope of the CR3022 mAb does not overlap with the hACE2 binding site on the RBD, allowing for sandwich ELISA and other assays. This mAb may be used, for example, to confirm that antigens are properly folded (although it may not allow discrimination of SARS-CoV-2 S from SARS CoV S), or as a competitor in serological assays. This protein was expressed using transient transfection in Expi293F cells, purified using protein A affinity chromatography, and characterized by SEC-HPLC, SDS-PAGE, and UV-Vis, with confirmation of binding and Kd assessment by BLI (Octet).

SARS-CoV-2 Receptor Binding Domain​​ (View the Certificate of Testing and current lot information​)
​The RBD is the portion of the S1 subunit of the SARS-CoV-2 Spike (S) protein that binds to the ACE2 receptor on the surface of human epithelial cells. This protein was expressed using transient transfection in Expi293F cells, and purified using IMAC (GE Healthcare Excel resin) and SEC (GE Healthcare S200). This monomeric protein was characterized by SEC-HPLC, SDS-PAGE, LAL, and UV-Vis, with confirmation of binding and Kd assessment by BLI (Octet). The protein we provide was originally made and characterized here, and we respectfully request citation of this work if you make use of the antigen. ​

​SARS-CoV-2 prefusion-stabilized trimeric Spike (View the Certificate of Testing and current lot information​) 
The SARS-CoV-2 Spike (S) protein binds to the ACE2 receptor and facilitates entry of viral particles into host cells. This trimeric protein was expressed using transient transfection in Expi293F cells, and purified using IMAC (Talon resin) and SEC (GE Healthcare S200). The protein was characterized by SEC-HPLC, SDS-PAGE, negative stain EM, LAL, and UV-Vis, with confirmation of binding and Kd assessment by BLI (Octet). The protein we provide was originally made and characterized here, and we respectfully request citation of this work if you make use of the antigen.  As this is a precious resource, aliquots of 0.5mg of this material can be requested, and in special circumstances we may consider requests for two aliquots (1.0mg).​​​