Cyanovirin-N could curb SARS-CoV-2 infection

A type of protein called cyanovirin-N is able to stop the transmission of the new variants of SARS-CoV-2 causing COVID-19, especially Delta and Òmicron. This molecule, similar to antibodies generated by vaccines, binds to the Spike protein of the coronavirus, blocking its entry into cells. This is according to a study in which researchers from the University of Lleida (UdL) and the Institute of Medical Research of Lleida (IRBLleida) participated, led by the Frederick National Laboratory for Cancer Research (USA) and published in the journal Proceedings of the National Academy of Sciences (PNAS). Researchers from the Institute for AIDS Research (IrsiCaixa) and the Federal University of Rio de Janeiro (Brazil) have also taken part in the study.

Lectins are proteins that bind carbohydrates produced by plants, algae and cyanobacteria. Some can neutralise viruses enveloped with external glycoproteins, offering an alternative therapeutic approach. Cyanovirin-N has previously been shown to be effective in preventing viruses such as Ebola, influenza, hepatitis C and HIV from entering cells, but until now has not been shown to be effective against SARS-CoV-2. The international team has demonstrated this in cell cultures in the laboratory and in animal models, finding a reduction in viral load in the nasal passages and lungs. The next step will be to test the efficacy of this compound in humans through clinical trials.

To perform its function, cyanovirin-N binds to a different part of the SARS-CoV-2 Spike protein than the active ingredient in vaccines, antiviral drugs and monoclonal antibody therapies, authorised by the European Medicines Agency for COVID-19. The use of these molecules would therefore be compatible with and could complement other therapeutic strategies.

"This lectin could have several advantages over vaccines. On the one hand, its effect would be more immediate, since it would not be necessary to wait for the immune system to generate antibodies. In addition, for people whose immune system does not respond correctly, such as people with immunodeficiencies, cyanovirin-N would be a good therapeutic option," says IrsiCaixa principal investigator Julià Blanco.

The compound could be easily obtained through plant production systems. "We know that large-scale production of this molecule is viable and economically feasible, even for low-income countries," adds ICREA research professor Paul Christou. In addition to him, this research has also involved the ETSEAFIV contract professor, Teresa Capell, the associate professor of Chemistry, Gemma Villorbina, and the full professor of the Faculty of Medicine, Gemma Villorbina and Manel Portero, senior lecturer at the Faculty of Medicine and researcher in the Metabolic Physiopathology research group at IRBLleida.

Text: Comunicación IrsiCaixa / Prensa UdL
Article Cyanovirin-N binds to select SARS-CoV-2 Spike oligosaccharides outside of the receptor binding domain and blocks infection by SARS-CoV-2