Analysis of IgM, IgA, and IgG Isotype Antibodies Directed Against SARS-CoV-2 Spike Glycoprotein and ORF8 in the Course of COVID-19

Denise Meinberger, Manuel Koch, Annika Roth, Gabriele Hermes, Jannik Stemler, Oliver A. Cornely, Thomas Streichert, Andreas R. Klatt

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Received date: 16th November 2020

Immunoassays are a standard diagnostic tool assessing immunity in severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection. However, immunoassays do not provide information about contaminating antigens or cross reaction and might exhibit inaccurate high sensitivity and low specificity. We aimed to gain insight into the serological immune response of SARS-CoV-2 patients by immunoblot analysis.
We analyzed serum immunoglobulins IgM, -A, and -G directed against SARS-CoV-2 proteins by immunoblot analysis from 12 infected patients. We determined IgG isotype antibodies by commercially available ELISA, and assessed clinical parameters of inflammation status, kidney, and liver injury.
We found evidence for antibody cross-reactivity, which calls into question a reliable assessment of serum samples tested negative for anti-SARS-CoV-2 antibodies by immunoassays. Nevertheless, for the detection of IgG anti-SARS-CoV-2 antibodies, our data suggest that the use of the spike glycoprotein in immunoassays should be sufficient to identify positive patients. Using a combination of the spike glycoprotein and the open reading frame 8 protein could prove to be the best for the detection of patients positive for anti-SARS-CoV-2 IgM antibodies. We found that the antibody response alone is not decisive for the course of the disease but the inflammation parameters are promising indicators.

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This is an abstract of a preprint hosted on a preprint server, which is currently undergoing peer review at Scientific Reports. The findings have yet to be thoroughly evaluated, nor has a decision on ultimate publication been made. Therefore, the results reported should not be considered conclusive, and these findings should not be used to inform clinical practice, or public health policy, or be promoted as verified information.

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