Researchers from the Netherlands and Germany were able to produce antibodies in the laboratory capable of blocking the action of the virus that causes Covid-19. The technique they employed is already used on a large scale to produce medicines against other diseases, which opens the possibility that these molecules are also used against the new disease, which has killed at least 250,000 people worldwide so far.
Under the leadership of Frank Grosveld, from the Erasmus Medical Center, and Berend-Jan Bosch, from the University of Utrecht (both Dutch institutions), the group of scientists has just published their work in the specialized journal Nature Communications.
The molecule they obtained is called a monoclonal antibody. This means that it was produced from clones of a single cell (hence the term "monoclonal", or "a clone"). In addition, monoclonal antibodies also connect to a single region of molecules foreign to the body to neutralize it. Its use to fight different types of cancer, attacking only tumor cells, has become increasingly common.
The monoclonal antibodies of the European study were created with the aim of neutralize the so-called protein S (spike), the molecular hook used by the coronavirus Sars-CoV-2 to connect to the surface of human cells. It is thought that, by blocking the action of protein S, the virus would not be able to invade cells, which would prevent infection.
To achieve this goal, the group worked with transgenic mice, whose organism is capable of producing antibodies whose composition is partially similar to that of human antibodies. Such animals were inoculated with the coronavirus S protein in order to stimulate the production of antibodies against it in their bodies – a process identical to vaccination of humans.
The monoclonal antibodies produced by the mice were "formatted" to assume a molecular configuration fully compatible with the human organism and started to be tested in direct contact with protein S and with a cell line of monkeys widely used in the laboratory.
In these tests, the molecules were able to block the entry of Sars-CoV-2 and a relative of it, Sars-CoV (the cause of the Sars epidemic, another respiratory disease, at the beginning of this century), in the cells. Interestingly, it is not clear how the new monoclonal antibody does this: protein S has continued to bind to the “lock” it uses to invade cells, but despite this, viruses were no longer able to enter.
In addition to trying to explain what the protective mechanism brought about by antibodies is, researchers also need to see how they would work in human patients, since, for now, the molecules have only been tested with cell cultures in the laboratory. According to the researchers, the monoclonal antibody has the potential to be used both in diagnosing the disease and for therapeutic purposes.