College researchers identify a sensitive and specific neutralization assay for SARS CoV-2 associated with COVID-19 patients
Investigators from The Ohio State University College of Veterinary Medicine in the laboratory of Dr. Shan-Lu Liu at the Center for Retrovirus Research and Department of Veterinary Biosciences have recently developed an assay to determine the presence and titers for neutralizing antibodies for SARS CoV-2 in serum or plasma. This method can be scaled up to facilitate the testing needs of the current crisis.
The COVID-19 pandemic sweeping the globe currently has no FDA-approved vaccine or therapeutic. Given this lack of specific pharmacological interventions, the only option left to stem the spread of the virus is to enact physical distancing measures that have caused a tremendous economic burden. With a vaccine not likely to be ready for widespread use for the next 1-2 years, physical distancing measures cannot be safely lifted until widespread COVID-19 testing is available. A major component of this testing capacity must be widespread antibody testing, or serologic testing, to identify individuals immune to SARS CoV-2, the causative agent of COVID-19. This “serum surveillance” will identify who can safely return to work without a strong risk of them contributing to the spread of the virus. Additionally, an accurate method for determining neutralizing antibody levels, or titers, in patient serum can help identify convalescent plasma with high neutralizing antibody titers from patients who have recovered from COVID-19. High neutralizing antibody titer convalescent plasma can be used to treat individuals with severe cases of COVID-19.
The current methods for determining patient antibody titers include Enzyme-Linked Immunosorbent Assay (ELISA) based assays and other neutralization assays. High volumes of ELISA assays require purification of large quantities of viral proteins. Neutralization assays of infectious SARS CoV-2 require biosafety level 3 facility. Additionally, ELISA assays measure total antibody binding and do not indicate protection. Assays to detect high neutralizing antibody titers will identify samples (serum or plasma) in which there are antibodies for binding the virus and blocking its subsequent infection of a new cell. These neutralizing antibodies are key for the clearance of, and immunity to, viral infection.
The lab team members who contributed to the assay development and are now involved in further assay tuning are (left to right) Mr. Jack Evans, Dr. Cong Zeng, Dr. Shan-Lu Liu (lab principal investigator), Dr. Yi-Min Zheng and Mr. Panke Qu.
The newly developed assay is an intron Gaussia luciferase-based neutralization assay, which provides a sensitive, specific, and simple method for determining the neutralizing antibody titers in patient serum or plasma. Results can currently be achieved in 24 hours, and a biosafety level 3 facility is not required. Additional development activities are underway to improve and scale-up the assay, as the importance and utility of this assay for SARS CoV-2 neutralizing antibodies is a critical step in both research and potentially widespread use throughout the world.