RBD-Based ELISA and Luminex Predict Anti-SARS-CoV-2 Surrogate-Neutralizing Activity in Two Longitudinal Cohorts of German and Spanish Health Care Workers

Ruth Aguilar, Xue Li, Claudia S. Crowell, Teresa Burrell, Marta Vidal, Rocio Rubio, Alfons Jiménez, Pablo Hernández-Luis, Dieter Hofmann, Hrvoje Mijočević, Samuel Jeske, Catharina Christa, Elvira D'Ippolito, Paul Lingor, Percy A. Knolle, Hedwig Roggendorf, Alina Priller, Sarah Yazici, Carlo Carolis, Alfredo MayorPatrik Schreiner, Holger Poppert, Henriette Beyer, Sophia E. Schambeck, Luis Izquierdo, Marta Tortajada, Ana Angulo, Erwin Soutschek, Pablo Engel, Alberto Garcia-Basteiro, Dirk H. Busch, Gemma Moncunill, Ulrike Protzer, Carlota Dobaño, Markus Gerhard

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The ability of antibodies to neutralize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important correlate of protection. For routine evaluation of protection, however, a simple and cost-efficient anti-SARS-CoV-2 serological assay predictive of serum neutralizing activity is needed. We analyzed clinical epidemiological data and blood samples from two cohorts of health care workers in Barcelona and Munich to compare several immunological readouts for evaluating antibody levels that could be surrogates of neutralizing activity. We measured IgG levels against SARS-CoV-2 spike protein (S), its S2 subunit, the S1 receptor binding domain (RBD), and the full length and C terminus of nucleocapsid (N) protein by Luminex, and against RBD by enzyme-linked immunosorbent assay (ELISA), and assessed those as predictors of plasma surrogate-neutralizing activity measured by a flow cytometry assay. In addition, we determined the clinical and demographic factors affecting plasma surrogate-neutralizing capacity. Both cohorts showed a high positive correlation between IgG levels to S antigen, especially to RBD, and the levels of plasma surrogate-neutralizing activity, suggesting RBD IgG as a good correlate of plasma neutralizing activity. Symptomatic infection, with symptoms such as loss of taste, dyspnea, rigors, fever and fatigue, was positively associated with anti-RBD IgG positivity by ELISA and Luminex, and with plasma surrogate-neutralizing activity. Our serological assays allow for the prediction of serum neutralization activity without the cost, hazards, time, and expertise needed for surrogate or conventional neutralization assays. Once a cutoff is established, these relatively simple high-throughput antibody assays will provide a fast and cost-effective method of assessing levels of protection from SARS-CoV-2 infection. IMPORTANCE Neutralizing antibody titers are the best correlate of protection against SARS-CoV-2. However, current tests to measure plasma or serum neutralizing activity do not allow high-throughput screening at the population level. Serological tests could be an alternative if they are proved to be good predictors of plasma neutralizing activity. In this study, we analyzed the SARS-CoV-2 serological profiles of two cohorts of health care workers by applying Luminex and ELISA in-house serological assays. Correlations of both serological tests were assessed between them and with a flow cytometry assay to determine plasma surrogate-neutralizing activity. Both assays showed a high positive correlation between IgG levels to S antigens, especially RBD, and the levels of plasma surrogate-neutralizing activity. This result suggests IgG to RBD as a good correlate of plasma surrogate-neutralizing activity and indicates that serology of IgG to RBD could be used to assess levels of protection from SARS-CoV-2 infection.

Original languageEnglish
JournalMicrobiology Spectrum
Volume11
Issue number1
DOIs
StatePublished - Jan 2023
Externally publishedYes

Keywords

  • ELISA
  • Luminex
  • SARS-CoV-2
  • antibodies
  • immunoglobulin Gspike protein
  • neutralization
  • receptor binding domain
  • symptoms

Fingerprint

Dive into the research topics of 'RBD-Based ELISA and Luminex Predict Anti-SARS-CoV-2 Surrogate-Neutralizing Activity in Two Longitudinal Cohorts of German and Spanish Health Care Workers'. Together they form a unique fingerprint.

Cite this