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Updated: Jan 7, 2026
Detection of SARS-CoV-2 Neutralizing Antibodies using High-Throughput Fluorescent Imaging of Pseudovirus Infection
Published on: June 5, 2021
Common human coronavirus-induced cross-reactive salivary antibodies exhibit neutralizing activity and protective
Pu Ou-Yang1, Ming-Kai Chuang2, Jann-Tay Wang3
1Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan.
Background:
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) still evolves and spreads worldwide. Mucosal immunity is the first line of defense against SARS-CoV-2 infections. We tested the hypothesis of whether salivary antibodies (sIgA or IgG) induced by common human coronaviruses (HCoVs) have cross-reactivities and neutralizing effects against SARS-CoV-2.
Methods:
Paired saliva and serum samples were collected from healthy young adults (n = 98) in 1993 and uninfected healthcare workers during the pandemic (n = 79). sIgA and IgG antibodies against SARS-CoV-2 and HCoV-229E were detected, respectively.
Results:
A moderate to strong positive correlation was found between levels of anti-SARS-CoV-2 and anti-HCoV-229E sIgA and IgG in saliva. Specific anti-S of SARS-CoV-2 IgA were found in 14 % of saliva, whereas neither anti-NP nor anti-S IgG were found in serum collected in the pre-pandemic era. Cross-reactivities of these sustained anti-HCoVs sIgA or IgG were enriched and confirmed by immunoblotting and also exhibited neutralizing activities against SARS-CoV-2 and its variants using Luminex-based assay. Furthermore, the incidence rate ratios of subsequent SARS-CoV-2 infection were significantly lower in the healthcare workers group with high salivary anti-HCoV-229E S1 sIgA.
Conclusion:
Our findings suggest that salivary anti-HCoV-229E S1 sIgA antibodies with cross-reactivities against SARS-CoV-2 S1 protein may pose protective potential against SARS-CoV-2.
