Dr. Lara Mahal
Professor of Chemistry, CERC in Glycomics
University of Alberta
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Glycomic Analysis of Clinical COVID-19 samples identifies alpha-2-6-sialylation as a severity marker and implicates complement cascade
Glycosylation is a key, often forgotten, modulator of the host-response to pathogens. It can control Fc-receptor interactions, downregulate immune responses (via Siglecs) and often acts as a receptor or co-receptor for pathogen interactions. Host response to COVID-19 infection has been varied, ranging from mild symptoms to ARDS and death. Herein, we apply our signature lectin microarray platform to analyze the glycomes of plasma from a range of COVID-19 patients and from autopsy samples. We identify 2-6-sialylation as a marker of severity. This glycan motif was enriched on complement proteins in severe COVID, even when protein levels remained steady. Similar staining patterns were observed for both complement proteins and alpha-2-6-sialic acid in the lungs of COVID-19 patients. Given the emerging importance of complement in COVID-19 progression, our data points to glycosylation of these proteins as an unexplored factor in this disease.