Diagnostic for Potential COVID-19 Immunity
A validated, high-throughput, cell-free test for SARS-CoV-2 neutralizing antibodies
The SARS-CoV-2 virus enters cells when the viral spike protein binds to the ACE2 protein on the surface of human cells. Antibodies that block this binding are thought to be responsible for immunity to the virus in people who recover from COVID-19. The antibody inhibition test described below can be used to determine the immune status of people who have recovered from COVID-19 and to track the duration of functional immunity over time.
Dr. Stephen Smith has developed a high-throughput, cell-free, quantitative assay for detecting anti-spike antibodies in human blood and determining their neutralizing potential. The test, which has been validated on a sample of 24 recovered COVID-19 patients and 30 pre-COVID controls, requires only microliter blood samples. Unlike other assays for neutralizing antibodies, it is easily scaled as it does not require live viruses or cells and does not necessitate technicians skilled in handling such materials. The assay uses recombinant proteins and instruments commonly available in commercial serological labs.
The assay begins with recombinant ACE2 protein attached to flow cytometry-compatible microbeads. The beads are incubated with recombinant spike protein with or without human blood samples, then washed. Next, a fluorescent probe that detects viral spike protein is added. If the samples contained antibodies that block spike protein binding to ACE2, flow cytometry will detect no fluorescence. Otherwise, a strong fluorescent signal will be observed. The ratio of each with-blood sample to a without-blood control gives a quantitative estimate of the strength of anti-viral immunity in each person tested.
This assay can be used to determine the immune status of people who have recovered from COVID-19 and to track the duration of functional immunity over time.
For vaccine development, the method could provide cost-effective, high-throughput screening of large numbers of serum samples. The assay could also be used to select the most effective options for convalescent plasma therapy. Finally, it could also be adapted for screening COVID-19 drug candidates that block binding of spike protein to ACE2.
Dr. Smith is interested in partnerships to scale up and commercialize this versatile, validated, cell-free assay for interactions between human ACE2 and SARS-CoV-2.
Stage of Development
- Preclinical validation
- Precommercial and commercial
- Assay development prior to regulatory approval
- Assay validation prior to development for market
- Licensing agreement
- Assay development
- High-throughput screening
- Collaborative research and development opportunity
- Sponsored research agreement
- Consultation agreement
Gniffke EP, Harrington WE, Dambrauskas N, Jiang Y, Trakhimets O, Vigdorovich V, Frenkel L, Sather DN, Smith SEP. Plasma from recovered COVID19 subjects inhibits spike protein binding to ACE2 in a microsphere-based inhibition assay. medRxiv 2020.06.09.20127050; doi:10.1101/2020.06.09.20127050