Development of a Simple, Highly Reliable Kit for Measuring COVID-19 Neutralizing Antibodies －Kit allows for the understanding of patient's immune status, promotes evaluation of vaccine performance－
October 30, 2020
Keio University School of Medicine
A research team at Keio University, through joint research with JSR subsidiary Medical & Biological Laboratories Co., Ltd., has succeeded in developing a kit for measuring novel coronavirus (SARS-CoV-2) neutralizing antibodies. The group was led by Professor Tsutomu Takeuchi and Project Assistant Professor Masaru Takeshita of the Division of Rheumatology, Department of Internal Medicine together with Professor Hideyuki Saya of the Division of Gene Regulation, Institute for Advanced Medical Research. This simple kit can produce results in less than two hours, and performance tests showed a high correlation with the results of neutralization tests using an infectious virus.
In general, when the patient has an infection, the immune system produces protective factors called antibodies. These antibodies recognize and bind to specific parts of a pathogen, but their ability to defend against infection varies by antibody. Antibodies that have the ability to bind to the critical sites of a virus, inhibit its function, and inactivate the virus are called "neutralizing antibodies." Measurement of the neutralizing antibodies to SARS-CoV-2 has required the experiments using an infectious authentic virus in a biosafety level (BSL) 3 facility that is capable of pathogen containment. In this joint research project, the team generated the receptor-binding site of the spike protein, which is important for the virus entry into the human cells, and the ACE2 protein, which is a receptor of human cells. Using these proteins, they reproduced the process of virus entry. The kit enables the measurement of neutralizing antibodies by quantifying the extent to which neutralizing antibodies in serum inhibit the process. And because the kit is virus-free, it can be used in normal BSL-1 laboratories.
It is currently being prepared for practical use as a research reagent by Medical & Biological Laboratories Co., Ltd. and is expected to greatly enhance understanding of a patient's immune status and promote evaluation of the performance of vaccines currently being developed.