Antibody test developed for COVID-19 that is sensitive, specific and
scalable

Date:
September 11, 2020
Source:
University of Texas at Austin
Summary:
An antibody test for the virus that causes COVID-19 is more accurate
and can handle a much larger number of donor samples at lower
overall cost than standard antibody tests currently in use. In
the near term, the test can be used to accurately identify the
best donors for convalescent plasma therapy and measure how well
candidate vaccines and other therapies elicit an immune response.



FULL STORY ==========================================================================
An antibody test for the virus that causes COVID-19, developed by
researchers at The University of Texas at Austin in collaboration with
Houston Methodist and other institutions, is more accurate and can handle
a much larger number of donor samples at lower overall cost than standard antibody tests currently in use. In the near term, the test can be used
to accurately identify the best donors for convalescent plasma therapy
and measure how well candidate vaccines and other therapies elicit an
immune response.


========================================================================== Additional uses coming later that are likely to have the biggest societal impact, the researchers say, are to assess relative immunity in those previously infected by the SARS-CoV-2 virus and identify asymptomatic individuals with high levels of neutralizing antibodies against the virus.

The UT Austin research team, led by Jason Lavinder, a research associate
in the Cockrell School of Engineering, and Greg Ippolito, assistant
professor in the College of Natural Sciences and Dell Medical School,
developed the new antibody test for SARS-CoV-2 and provided the viral
antigens for this study via their UT Austin colleague and collaborator, associate professor Jason McLellan. Other UT Austin team members are
Dalton Towers and Jimmy Gollihar. The work was published this week in
The Journal of Clinical Investigation.

"This is potentially game-changing when it comes to serological testing
for COVID-19 immunity," Lavinder said. "We can now use highly scalable, automated testing to examine antibody-based immunity to COVID-19 for
hundreds of donors in a single run. With increased levels of automation, limited capacity for serological testing can be rapidly addressed
using this approach." The gold standard of COVID-19 antibody testing
measures the amount of virus neutralizing (VN) antibodies circulating
in the blood, because this closely correlates with immunity. However,
this kind of antibody testing is not widely available because it's
technically complex; requires days to set up, run and interpret; and
needs to be performed in a biosafety level 3 laboratory.

The research team, therefore, looked to another type of test, called ELISA assays, that can be implemented and performed with relative ease in a
high- throughput fashion and are widely available and extensively used
in clinical labs across the world. The ELISA tests, or enzyme-linked immunosorbent assays, look at whether antibodies against specific
SARS-CoV-2 proteins are present and produce a quantitative measure of
those antibodies.

The goal of the study was to test the hypothesis that levels of
antibodies that target two regions of the virus's spike protein -- spike ectodomain (ECD) and receptor binding domain (RBD) -- are correlated
with virus neutralizing antibody levels, making these more accessible, easier-to-perform ELISA tests a surrogate marker to identify plasma
donors with antibody levels above the recommended U.S. Food and Drug Administration threshold for convalescent plasma donation.

In collaboration with UT Austin, Penn State University and the U.S. Army Medical Research Institute of Infectious Diseases, study authors James M.

Musser, M.D., Ph.D., and Eric Salazar, M.D., Ph.D., physician scientists
at Houston Methodist, used the new test to evaluate 2,814 blood samples
used in an ongoing study of convalescent plasma therapy. Houston
Methodist became the first academic medical center in the nation to
transfuse plasma from recovered individuals into COVID-19 patients.

The researchers found that the ELISA tests had an 80% probability
or greater of comparable antibody level to VN levels at or above the FDA-recommended levels for COVID-19 convalescent plasma. These results
affirm that all three types of tests could potentially serve as a
quantitative target for therapeutic and prophylactic treatments.

Ultimately, the study successfully concluded that anti-RBD or anti-ECD
antibody levels can serve as a surrogate for VN levels to identify
suitable plasma donors and that these alternate ELISA tests may provide critical information about COVID-19 immunity.

"This research required a perfect storm at the university, which included
the extraordinary combination of a world-famous coronavirus structural
biology lab, a nimble and passionate visiting army scientist, and the
highest echelons of the university's administration who were committed to bringing our extensive research programs to bear on the COVID-19 crisis," Ippolito said.

This study was supported by funding from the National Institutes of
Health, the Fondren Foundation, the National Institute of Allergy
and Infectious Diseases, the Army Research Office, Houston Methodist
Hospital, Houston Methodist Infectious Diseases Research Fund, Houston Methodist Research Institute and seed funding from the Huck Institutes
of the Life Sciences for the studies at Penn State, together with the
Huck Distinguished Chair in Global Health award.

Funding was also provided through the CARES Act, with programmatic
oversight from the Military Infectious Diseases Research Program.


========================================================================== Story Source: Materials provided by University_of_Texas_at_Austin. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Eric Salazar, Suresh V. Kuchipudi, Paul A. Christensen, Todd
Eagar, Xin
Yi, Picheng Zhao, Zhicheng Jin, S. Wesley Long, Randall J. Olsen,
Jian Chen, Brian Castillo, Christopher Leveque, Dalton Towers,
Jason J.

Lavinder, Jimmy Gollihar, Jose A. Cardona, Gregory C. Ippolito,
Ruth H.

Nissly, Ian Bird, Denver Greenawalt, Randall M. Rossi, Abhinay
Gontu, Sreenidhi Srinivasan, Indira Poojary, Isabella M. Cattadori,
Peter Hudson, Nicole M. Josleyn, Laura Prugar, Kathleen E. Huie,
Andrew S.

Herbert, David W. Bernard, John M. Dye, Vivek Kapur, James
M. Musser.

Convalescent plasma anti-SARS-CoV-2 spike protein ectodomain
and receptor binding domain IgG correlate with virus
neutralization. Journal of Clinical Investigation, 2020; DOI:
10.1172/JCI141206 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200911141705.htm

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