An international team of scientists has identified and finalized new antibody fragments for SARS-CoV-2. MedicalXpress and EurekAlert write about it.
“The nanobodies, as noted in the study, are smaller than classic antibodies, so they penetrate tissue better and can be produced in large quantities. The authors of the paper were able to combine the nanobodies into potentially particularly effective molecules that simultaneously attack different parts of the virus.
According to Dr. Florian Schmidt, the immune system produces an almost infinite number of different antibodies, but few of them can defeat the coronavirus. As the scientist explained, the SARS-CoV-2 surface protein was first injected into alpacas and llamas: the immune system reproduced antibodies to it.
“In total, we obtained dozens of antibodies, which we analyzed further,” said Dr. Paul-Albert Koenig, lead author of the study and head of the nanobodies department at the Faculty of Medicine at the University of Bonn.
The four nanobodies proved effective against the pathogen in cell cultures.
The protein-ship is important for infection, Koenig reminded us: it acts like Velcro, with which the pathogen attaches itself to the cell. The velcro then changes its structure, discarding a component important for attachment, and mediates the fusion of the viral envelope with the cell.
“Nanobody also triggers this structural change before the virus meets its target cell. <...> The change is likely to be irreversible. Therefore, the virus will no longer be able to bind to cells and infect them,” the scientist explained.
In addition, the researchers used another important advantage of nanotelles: their structure allows the formation of molecules with high efficiency. One of the authors of the study, Martin Hellberg, said that they “stitched” together nanobodies that bind to two different regions of the coronavirus spike protein. This variant helped block the virus’s ability to spread between human cells. In addition, the combined variant of the nanobodies also worked with the mutated virus.
“Consequently, there is an extremely low risk that the virus will become resistant to these combined nanobodies,” the scientist noted.
Hellberg suggested that the nanobodies could be turned into a drug in addition to vaccination against the coronavirus.