As the vaccine campaign against COVID-19 ramps up in the US, scientists are now looking at long-term improvements to the vaccines that are currently available. Particularly, scientists aim to develop next-generation vaccines that further minimize side effects and tackle the challenge of fully eliminating the severe disease associated with overactive immune responses to COVID-19. Researchers at the University of Amsterdam and Sanquin Research in the Netherlands identified a single major difference between mild and severe cases of COVID-19 infection. That difference is a single missing sugar molecule in the antibodies produced in patients with severe disease.
Researchers isolated antibodies from patient samples and looked at a chain of sugars attached to a specific part of the antibody. In the scientific world, “sugar” describes a large group of related molecules which includes sucrose (table sugar), glucose, and others. They found that the sugars attached to the antibody were highly variable, which was expected. However, samples collected from patients suffering from severe disease often contained antibodies without a specific kind of sugar: fucose. When this sugar is missing, the resulting antibody leads to major inflammation events, a hallmark symptom of severe COVID-19. They correlated the production of these antibodies to the production of inflammation-related proteins in blood samples. Hence, this one sugar likely plays a major role in the progression of COVID-19, especially severe cases.
The impacts and implications of this study are far-reaching. First, scientists may develop booster vaccines that force the production of antibodies incorporating this sugar. This information may also be used to create new antibody treatments to initiate and bolster a healthier immune response for severe cases of COVID-19. Lastly, this research begins to close the door on one of the most pervasive questions in COVID-19 research: why do some folks suffer from severe disease? Likely, it’s the absence of a single sugar molecule.
This study was a collaborative effort co-authored by Mads Delbo Larsen, Erik L. de Graaf, and Myrthe E. Sonneveld from the Landsteiner Laboratory at the University of Amsterdam and coordinated by the corresponding author Gestur Vidarsson from the Department of Experimental Immunohematology at Sanquin Research in Amsterdam, Netherlands.
Managing Correspondent: Koby Ljunggren
Press Article: Afucosylated antibodies to SARS-CoV-2 account for more severe disease. Sanquin News.
Original Article: Afucosylated IgG characterizes enveloped viral responses and correlates with COVID-19 severity. Science.
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