Rapid, Point of Care Detection of Neutralizing Antibodies Against A Virus

Technology

This technology is a point-of-care testing strip, with a physical design akin to that of a pregnancy testing kit. Unique to this invention are the individual components consisting of a) a purified human domain of ACE2 protein (a coronavirus Spike protein target) that is embedded at the “control” line, and b) a recombinant protein that will bind antibodies bound to truncated Spike protein (the receptor binding domain portion) that is embedded at the ”test” line. 

To use this test, an individual will first mix a blood sample with purified, truncated coronavirus Spike proteins supplied by the test kit. When an individual has developed immunity against coronavirus infection, this individual will produce antibodies that can neutralize Spike in the mixing reaction. Subsequently, when this mixture is spotted onto the testing strip, unbound Spike will bind to the “control” protein line and display a visible solid line, indicating the level of non-neutralized Spike. Antibody-bound neutralized Spike will bind to the “test” protein line and display an intense visible solid line, indicating the level of antibodies in the individual that neutralized Spike. When an individual does not have coronavirus immunity or when the immunity has waned, the “test” protein line will not light up or will only show a faint line, respectively. Therefore, by reading out the intensity of the “test” protein line, one can quickly determine an individual’s level of protective immunity against COVID-19 infection.

Problem Addressed

With COVID-19 vaccines becoming globally available, monitoring the degree of immune protection is equally important as detecting the spread of viral infection when forming workforce and public health-related guidelines. To tell if an individual is protected from COVID-19, clinicians require knowledge of neutralizing antibody levels in blood. However, conventional lab methods hinder commercial adoption due to expensive reagent costs, slow turnaround time, and the requirement of a central facility with well-trained personnel. The inventors overcame these problems by designing a field-deployable testing strip for reading out COVID-19 neutralizing antibodies in the blood. This invention leverages a lateral flow assay format along with engineered and carefully tested design parts to detect neutralizing antibodies against SARS-CoV-2 coronavirus with robust sensitivity and specificity.

Advantages

• Field-deployable, rapid LFA antibody test for COVID-19

• Signal intensity at the “test” line is directly proportional level of neutralizing antibodies

• Built-in molecular controls for low rates of false positive and false negative

• Scalable design and easy-to-administer diagnostic strips for wide-scale screening

• Enable monitoring of vaccine efficacy and determination of vaccine booster timing

• Enable serial monitoring of healthcare workers and high-risk essential workers

• Enable more effective screening of convalescent plasma donors

• Prototype successfully developed and all SOPs necessary to reproduce the prototype device are available

• ROC curves have been generated via testing clinical samples