The ANSM has decided to withdraw three antibody treatments for Covid-19 patients. They would not be effective against the Omicron variant. But immune cells from sharks could become the basis for other coronavirus treatments, including the Omicron variant, alongside vaccination.
- The sharks observed were nurse sharks.
- Scientists have tested over a billion VNARs.
- The authors of this study are currently testing these VNARs against cancer.
What if the shark became man’s best friend? Its immune cells could be valuable for human health. In a study published in the journal Natureresearchers show that certain proteins, called VNARs, essential to the immune system of these fish, are able to prevent the infection of human cells by coronaviruses, and even the Omicron variant of SARS-CoV-2. A hope while the ANSM has just restricted the use of three synthetic antibody treatments authorized in France which would not be effective against the Omicron variant. Only one of them, Romapreve, continues to be used against serious forms linked to an infection by the Delta variant.
Proteins with delayed actions
But new hope in the care of Covid patients could therefore come from shark antibodies. The authors of the research that opens this track are scientists from the University of Wisconsin-Madison. They point out that VNARs are one-tenth the size of human antibodies. “These little antibody-like proteins can get into nooks and crannies that human antibodies can’t get to, explains Aaron LeBeau. They can form these very unique geometries. This allows them to recognize structures in proteins that are not visible to our human antibodies.” This ability of VNARs to bind to infectious proteins in a unique way gives them this ability to stop the infection. In total, two VNARs were selected by the researchers: 3B4 and 2C02. The first prevents the virus from attaching to human cells, the second deactivates the Spike protein. According to the researchers, VNARs 3B4 is the most effective because it is able to act against different types of coronaviruses, including the Delta variant of SARS-CoV-2. “This research was conducted before the discovery of the omicron variant, but initial models suggest that VNAR would remain effective against this new version.”says Aaron LeBeau.
Insurance against the future
According to him, this protein would even be a potential tool against viruses that have not yet infected humans.What we’re doing is preparing an arsenal of shark VNAR therapies that could later be used for future SARS outbreaks, explains the researcher. It’s a kind of insurance against the future.” These shark proteins neutralized WIV1-CoV, a coronavirus capable of infecting human cells but currently only circulating in bats, where SARS-CoV-2 likely originated. “The big problem is that a number of coronaviruses are about to emerge in humans“, insists Aaron LeBeau. The drugs created would likely involve a cocktail of several shark VNARs to maximize their effectiveness. The authors explain that this new class of drugs is cheaper and easier to manufacture than human antibodies, and can be administered in the body by various routes, but it has not yet been tested in humans.It would be intended for people who do not respond well to vaccination, such as those who suffer from immunosuppression.