COVID-19 Drug Discovery
Assays for SARS-CoV-2 viral entry.
Pseudo SARS-CoV-2 virus and pseudo host BacMam enables basic research and drug screening.
- Detect host-pathogen interaction in living cells.
- Identify therapeutic drugs that block ACE2-mediated viral entry.
- Screen for neutralizing antibodies to SARS-CoV-2 spike and emerging spike variants.
- Cost effective screening with minimal safety requirements.
- Your choice of host cell.
Pseudo SARS-CoV-2 is a BacMam vector pseudotyped with spike protein. Pseudovirus enters the host cell through interactions with the ACE2 protein and TMPRSS2 protein. Once inside the cell, BacMam does not replicate, but delivers a genetically-encoded, fluorescent reporter that expresses bright red or green fluorescence in the host cell nucleus. When viral entry is successfully blocked, the host cell nucleus is dark. Pseudo SARS-CoV-2 is safe to use with no risk of infection and requires only BSL-1 handling.
Pseudo Host Cells
BacMam pseudovirus enters human airway cells and other primary cells that express the ACE2 and TMPRSS2 protein, but not all cells express these host proteins. To cells into pseudo host cells, we offer red and green fluorescent ACE2 and TMPRSS2 in BacMam expression vectors. Transduce cells with BacMam expressing ACE2 and TMPRSS2, and the following day pseudo host cells are ready for the pseudo SARS-CoV-2 viral entry assay. If the pseudovirus enters the cells, it will produce bright fluorescence in the nucleus, a signal that can be blocked if viral entry is blocked. A significant advantage of creating pseudo host cells is that compounds can be screened using standard cell lines that are compatible with high throughput screening. Most laboratories can be screening for blocking agents within a few days, with a minimum of changes to their work flow or safety regulation requirements.
For additional details on the individual components of these assays, see our Reagents for SARS-CoV-2 Research page.
Green/Red Ratiometric Assay of Pseudovirus Entry
BacMam vectors deliver red fluorescent ACE2 and TMPRSS2 to mammalian cells. This pseudo host mimics human airway cells for a robust live cell assay of viral entry. BacMam virus pseudotyped with the spike protein enter these cells and express bright green fluorescent protein in the pseudo host cell nucleus. Pseudovirus entry will result in high green to red fluorescence ratios, while successful blockade of entry will produce low green to red ratios. This assay can also be done with a green fluorescent ACE-2 and a pseudovirus with a red fluorescent reporter.
Pseudo SARS-CoV-2 virus is an enveloped virus that presents the full length spike protein on the viral surface membrane with the same topology as SARS-CoV-2. The spike protein is quite concentrated and oriented perpendicular to the membrane such that multiple antibody binding sites are available and presented in a structurally relevant way. Two versions are available, one with the sequence identified in the original Wuhan reference specimen and the newer D614G mutant that first appeared in Europe and is rapidly replacing the Wuhan strain.