Summary Series

 

Development and Validation of a Multiplex, Bead-Based Assay to Detect Antibodies Directed Against SARS-CoV-2 Proteins

By: Dave Lowe

 

 

Key Takeaways

  • A new diagnostic tool to determine SARS-CoV-2 antibody status in transplant patients 
  • Multiplex assay detecting antibodies to five distinct SARS-CoV-2 proteins 
  • Non-cross-reactive with community coronaviruses, SARS, and MERS 
  • Assay displays 98.6% specificity and 100% sensitivity

 

Introduction

The development of reliable and effective antibody assays will be crucial in understanding the epidemiology of COVID-19. Understanding the nature of antibody responses to this infection will also be key to evaluating the efficacy of potential future vaccines. In addition, transplant patients remain at significant risk of increased morbidity and mortality, so the accurate and timely identification of COVID-19 specific antibody responses provides more targeted patient management opportunities.

 

Comprehensive SARS-CoV-2 Screening Capability

The SARS-CoV-2 genome encodes four major structural proteins; spike, envelope, membrane, and nucleocapsid. Most commercially available tests target either the spike subunits or nucleocapsid. The LABScreen ™ COVID Plus assay targets these proteins and identifies antibody responses to community coronaviruses, original SARS and MERS viruses, some of which have been shown to cross-react with SARS-CoV-2 in other tests.

 

Data Analysis

The assay was validated using patients confirmed positive for SARS-CoV-2, with 100% showing positivity with at least three of the targets included in the multiplex panel. Screening pre-COVID-19 samples showed no SARS-CoV-2 reactivity but as expected, it indicated most individuals have significant immunity to community coronaviruses. Subsequent screening of transplant candidates (n=51) using samples collected in May 2020 showed three positive samples. Two were reactive with all five proteins, whilst one reacted solely against the full spike protein. Overall, the LABScreen COVID Plus assay displays specificity and sensitivity of 98.6 and 100%, respectively.

 

Clinical Utility

Designed to run on the Luminex platform and in conjunction with the LABScreen family of HLA antibody detection products, COVID Plus provides a unique diagnostic tool that delivers a semi- quantitative assessment of the antibody response to SARS-CoV-2 It can be seamlessly integrated into a routine laboratory workflow providing critical information for transplant clinicians and surgeons. Furthermore, the comprehensive assessment of the COVID-19 antibody response afforded by COVID Plus will be an invaluable tool for assessing future vaccine efficacy in transplant patients and the wider community.

Reference:

Bray RA, Lee JH, Brescia P, Kumar D, Nong T, Shih R, Woodle ES, Maltzman JS, Gebel HM. Development and Validation of a Multiplex, Bead-Based Assay to Detect Antibodies Directed Against SARS-CoV-2 Proteins. Transplantation. 2020 Dec 2. doi: 10.1097/TP.0000000000003524. Epub ahead of print. PMID: 33273320.