Cross-validation of ELISA and a portable surface plasmon resonance instrument for IgG antibody serology with SARS-CoV-2 positive individuals

Analyst. 2021 Jul 26;146(15):4905-4917. doi: 10.1039/d1an00893e.

Abstract

We report on the development of surface plasmon resonance (SPR) sensors and matching ELISAs for the detection of nucleocapsid and spike antibodies specific against the novel coronavirus 2019 (SARS-CoV-2) in human serum, plasma and dried blood spots (DBS). When exposed to SARS-CoV-2 or a vaccine against SARS-CoV-2, the immune system responds by expressing antibodies at levels that can be detected and monitored to identify the fraction of the population potentially immunized against SARS-CoV-2 and support efforts to deploy a vaccine strategically. A SPR sensor coated with a peptide monolayer and functionalized with various sources of SARS-CoV-2 recombinant proteins expressed in different cell lines detected human anti-SARS-CoV-2 IgG antibodies in clinical samples. Nucleocapsid expressed in different cell lines did not significantly change the sensitivity of the assays, whereas the use of a CHO cell line to express spike ectodomain led to excellent performance. This bioassay was performed on a portable SPR instrument capable of measuring 4 biological samples within 30 minutes of sample/sensor contact and the chip could be regenerated at least 9 times. Multi-site validation was then performed with in-house and commercial ELISA, which revealed excellent cross-correlations with Pearson's coefficients exceeding 0.85 in all cases, for measurements in DBS and plasma. This strategy paves the way to point-of-care and rapid testing for antibodies in the context of viral infection and vaccine efficacy monitoring.

MeSH terms

  • Antibodies, Viral
  • COVID-19 Vaccines
  • COVID-19*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Immunoglobulin G
  • SARS-CoV-2*
  • Sensitivity and Specificity
  • Spike Glycoprotein, Coronavirus
  • Surface Plasmon Resonance

Substances

  • Antibodies, Viral
  • COVID-19 Vaccines
  • Immunoglobulin G
  • Spike Glycoprotein, Coronavirus