ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to more than 4 million confirmed infections worldwide and over 300,000 deaths. While Remdesivir has recently received FDA emergency use authorization for treatment of SARS-CoV-2 infection, convalescent plasma (CP) with high titers of SARS-CoV-2 neutralizing antibodies (NAbs) from recovered donors remains a promising and widely accessible method to mitigate severe disease symptoms. Here, we describe the development and validation of a cell-free neutralization PCR assay using SARS-CoV-2 spike protein S1 and human ACE2 receptor-DNA conjugates. By comparing with samples collected prior to the outbreak, we confirmed that NAbs were specifically detected in COVID-19 cases. Using our unique assay, the NAb signals are detectable as early as 10 days after onset of symptoms and continue to rise, plateauing after 18 days. Notably, we showed that the use of a licensed pathogen reduction technology to inactivate potentially contaminating infectious pathogens in CP did not alter NAb signals, paving a path to safely administer effective CP therapies. The described neutralization PCR assay can serve as a qualification tool to easily identify suitable CP donors of a potentially lifesaving therapy. In addition, this assay tool is readily deployable in standard laboratories with biosafety level 2 capability, and can yield results within 2-3 hrs. This advancement can facilitate research on factors driving diverse COVID-19 disease manifestations, help evaluate the impact of various CP processing protocols on CP therapeutic efficacy and assist in accelerating vaccine efficacy assessment.
Competing Interest Statement
K.D., D.K., P.V.R., D.S., C.T.T are employees of Enable Biosciences. The convalescent plasma used in this study was collected for clinical use by independent blood centers using licensed plasma or platelet processing systems manufactured by Cerus Corporation, for which multiple authors (A.B., L.M.C) are shareholders and employees.
Clinical Trial
The study was conducted based on institutional approved IRB #20180015 (by Western IRB) to investigate neutralizing antibodies in COVID-19 patients, and does not constitute any interventions, thus not meeting definition of clinical trails per NIH guidelines.
Funding Statement
The study is funded in part by NIH SBIR 2R44DK110005-02 and 2RAI141118-02 to Enable Biosciences. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
The study was conducted based on IRB approval to Enable Biosciences IRB #20180015 (approved by Western IRB). All samples collected outside of Enable Biosciences were received as de-identified specimens.
All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.
Yes
I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).
Yes
I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.
Yes
Data Availability
The datasets and reagents generated and analyzed during the current study are available from the corresponding author upon reasonable request.