A group of Canadian researchers has developed a set of standardized, high-throughput serological assays to detect antibodies against SARS-CoV-2. Multiple studies estimating the seroprevalence of various populations in Canada – including over half of those funded by the CITF – use this platform, making it possible to harmonize and compare their results nationwide. In a preprint, not yet peer-reviewed, and partly funded by the CITF, the team led in part by Dr. Anne-Claude Gingras from Toronto’s Lunenfeld-Tanenbaum Research Institute, Dr. Marc-André Langlois from the University of Ottawa, and Dr. Yves Durocher from the National Research Council of Canada, describe their multi-faceted detection of the antibody response to SARS-CoV-2 infection and vaccination. 

This unique platform enables the simultaneous detection of IgG antibodies recognizing the SARS-CoV-2 spike (S) trimer, its receptor binding domain (RBD), and nucleocapsid (N) proteins (see figure below) as well as the ability of the antibodies to neutralize the virus.

Key points:

Figure 1. A SARS-CoV-2 viral particle with labelled nucleocapsid (N) and spike (S) proteins. The virus’ receptor binding domain (RBD), housed on the S protein, is also shown. The tests developed by Drs. Gingras and Langlois can detect antibodies against all three of these viral antigens.

  • Protocols developed can be used to detect, in high-throughputHigh-throughput describes the scaling-up and automation of laboratory tests to process large numbers of samples at once. , antibodies to the main SARS-CoV-2 antigens (S, RBD, and N) from serum and dried blood spots (DBS). Further, the surrogate virus neutralization assay detects antibodies capable of disrupting the interaction between S and the ACE2 receptor.
  • All reagents used in this study were generated at the National Research Council of Canada, and are made available across the country to enable harmonization of standardized, automated high-throughput or manual serological assays. This has the advantage of enabling researchers to compare and aggregate data.
  • The automated ELISAsAn enzyme-linked immunosorbent assay (ELISA) is a laboratory technique used to detect the presence of antigens in a biological sample. An ELISA, like other types of immunoassays, relies on antibodies to detect a target antigen (e.g., viral proteins) using highly specific antibody-antigen interactions. have been optimized in two independent sites: Toronto (Gingras lab) and Ottawa (Langlois lab).
  • These assays have been calibrated using reference standards from the World Health Organization to provide quantitative output in binding antibody units (BAU). This enables cross-comparison of serological responses worldwide to better evaluate vaccination strategies and the evolution of global immunity to SARS-CoV-2.

This made-in-Canada system has now profiled over 150,000 unique samples and more than half of CITF-funded serosurveys use this platform. Most importantly, the harmonized high-throughput serological assays enable the comparison of data and aggregation of results nationwide.

Colwill K, Galipeau Y, Stuible M, Gervais C, Arnold C, Rathod B, Abe KT, Wang JH, Pasculescu A, Maltseva M, Rocheleau L, Pelchat M, Fazel-Zarandi M, Iskilova M, Barrios-Rodiles M, Bennett L, Yau K, Cholette F, Mesa C, Li AX, Paterson A, Hladunewich MA, Goodwin PJ, Wrana JL, Drews SJ, Mubareka S, McGeer AJ, Kim J, Langlois M-A, Gingras A-C, Durocher Y. A “Made-in-Canada” serology solution for profiling humoral immune responses to SARS-CoV-2 infection and vaccination. bioRxiv. 2021 Oct 26. doi: 10.1101/2021.10.25.21265476v1