Multiplex detection and dynamics of IgG antibodies to SARS-CoV2 and the highly pathogenic human coronaviruses SARS-CoV and MERS-CoV
Autor
Ayouba, Ahidjo
Thaurignac, Guillaume
Morquin, David
Tuaillon, Edouard
Raulino, Raisa
Nkuba, Antoine
Lacroix, Audrey
Vidal, Nicole
Foulongne, Vincent
Le Moing, Vincent
Reynes, Jacques
Delaporte, Eric
Peeters, Martine
Institución
Resumen
Background: Knowledge of the COVID-19 epidemic extent and the level of herd immunity is urgently needed to
help manage this pandemic.
Methods: We used a panel of 167 samples (77 pre-epidemic and 90 COVID-19 seroconverters) and SARS-CoV1,
SARS-CoV2 and MERS-CoV Spike and/or Nucleopcapsid (NC) proteins to develop a high throughput multiplex
screening assay to detect IgG antibodies in human plasma. Assay performances were determined by ROC curves
analysis. A subset of the COVID-19+ samples (n = 36) were also tested by a commercial NC-based ELISA test
and the results compared with those of the novel assay.
Results: On samples collected ≥14 days after symptoms onset, the accuracy of the assay is 100 % (95 % CI:
100−100) for the Spike antigen and 99.9 % (95 % CI:99.7−100) for NC. By logistic regression, we estimated
that 50 % of the patients have seroconverted at 5.7 ± 1.6; 5.7 ± 1.8 and 7.9 ± 1.0 days after symptoms onset
against Spike, NC or both antigens, respectively and all have seroconverted two weeks after symptoms onset. IgG
titration in a subset of samples showed that early phase samples present lower IgG titers than those from later
phase. IgG to SARS-CoV2 NC cross-reacted at 100 % with SARS-CoV1 NC. Twenty-nine of the 36 (80.5 %)
samples tested were positive by the commercial ELISA while 31/36 (86.1 %) were positive by the novel assay.
Conclusions: Our assay is highly sensitive and specific for the detection of IgG antibodies to SARS-CoV2 proteins,
suitable for high throughput epidemiological surveys. The novel assay is more sensitive than a commercial
ELISA.