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COVID-19 : The glaze that camouflages the coronavirus

The communication between the cells of the body is something that occurs thanks to glycans, which are nothing more than chains of sugars. Virtually all biological structures are covered by a layer of these. It is, therefore, a fundamental layer in infectious processes, in which a pathogen interacts with the surface of our cells. This is exactly what happens with the coronavirus.

The spike protein, the main route of entry of the virus into our body, is more than two-thirds coated with glycans, as demonstrated in a study by the University of California. Rommie Amaro, one of the researchers leading the work, explains to El País that “sugars escape what we can see under the microscope. They move too fast to be seen with this technologyFor this reason, his team decided to use computer simulators in order to reconstruct the glaze that covers this protein and thus understand their role during contagion.

How sugars work

In these cases, in addition, they are fundamental for two reasons: they stabilize the spicule in a way that fits the ACE2 receptors on the cells of our body and in this way the infection begins. Amaro, together with his team, has been able to show that removing part of the glycans the spicule is destabilized, weakening the binding to receptors.

Moreover, this frosting also helps the coronavirus to ‘camouflage’ itself within the immune system. “If protein swarmed around ‘naked’, our immune system would immediately recognize her as a threat. Thanks to glycans, the virus does not seem strange, “says Elisa Fadda, a researcher at the University of Maynooth (Ireland). In this way, the virus goes unnoticed and the immune system does not distinguish it from its own cells. In the image that heads the article, this frosting is represented by the color dark blue, covering much of the pathogen (light blue).

The results of this study will help in the search for new treatments for the disease. Furthermore, the coating is different depending on the part of the protein: a 62% at the top. Furthermore, the work reveals that the frosting is less effective in protecting the protein from smaller molecules, capable of accessing 80% of the entire surface. The fact of being able to determine the most vulnerable parts can be of help in the goal of finding new drugs more effective in treating disease.

The importance for vaccines

The results of this work also result from vital to the development of effective vaccines against COVID. Those created by Pfifer and BioNTtech, Moderna and AstraZeneca use their own cellular machinery to create copies of the coronavirus spike protein and thus generate an immune response without suffering the disease.

During the last months, work has been done on the development of techniques to analyze the various sugars that surround this protein generated by the vaccines, in order to compare them with the real spike of the pathogen. In both cases the cells make the two proteins, but they are slightly different in their glazes. “The differences are minimal, in no case so dramatic as to affect the effectiveness of vaccines“recalls Fadda.