Importance of Covid-19 Antibody Tests... Technology NetworksConserved Antibody Binding-Site Identified Across COVID-19 ...Most antibody-testing kits look for the N protein to determine if a person was previously infected with the virus — as opposed to diagnostic tests ...9 hours ago
“We discovered new features about the N protein structure that could have large implications in antibody testing and the long-term effects of all SARS-related pandemic viruses,” said Deb Kelly, professor of biomedical engineering (BME), Huck Chair in Molecular Biophysics and director of the Penn State Center for Structural Oncology, who led the research. “Since it appears that the N protein is conserved across the variants of SARS-CoV-2 and SARS-CoV-1, therapeutics designed to target the N protein could potentially help knock out the harsher or lasting symptoms some people experience.”
Most of the diagnostic tests and available vaccines for COVID-19 were designed based on a larger SARS-CoV-2 protein — the Spike protein — where the virus attaches to healthy cells to begin the invasion process.
The Pfizer/BioNTech and Moderna vaccines were designed to help recipients produce antibodies that protect against the Spike protein. However, Kelly said, the Spike protein can easily mutate, resulting in the variants that have emerged in the United Kingdom, South Africa, Brazil and across the United States.
Unlike the outer Spike protein, the N protein is encased in the virus, protected from environmental pressures that cause the Spike protein to change. In the blood, however, the N protein floats freely after it is released from infected cells. The free-roaming protein causes a strong immune response, leading to the production of protective antibodies. Most antibody-testing kits look for the N protein to determine if a person was previously infected with the virus — as opposed to diagnostic tests that look for the Spike protein to determine if a person is currently infected.
“Everyone is looking at the Spike protein, and there are fewer studies being performed on the N protein,” said Michael Casasanta, first author on the paper and a postdoctoral fellow in the Kelly laboratory. “There was this gap. We saw an opportunity — we had the ideas and the resources to see what the N protein looks like.”