Chinese researchers have recently been working on a new antibody from a dozen patients cured of the coronavirus. If the latter has a strong neutralizing power, the target is not the same as that usually targeted by other antibodies!
At the end of May 2020, we were talking about research conducted in Taiwan. Scientists have indeed discovered a monoclonal antibody capable of preventing the SARS-CoV-2 (Covid-19) virus from entering the human body. There is talk of a virus inhibition capacity ranging from 90% to 98% .
A study led by the Beijing Institute of Biotechnology (China) and published in the journal Science on June 22, 2020 identified a new antibody effective against Covid-19. Extracted from the blood of a dozen cured people, this antibody named 4A8 would have a strong neutralizing power according to the researchers. However, this antibody is special in that it attacks another part of the protein responsible for the infection!
Recall that the inoculation of a vaccine means the presence of a harmless version of a microorganism. This makes it possible to produce many antibodies in order to fight the undesirable microorganism. Thus, the antibodies bind very specifically to certain molecules of the virus (epitopes). In the case of SARS-CoV-2, the most common epitope is the viral protein S (Spike), responsible for the interaction with the ACE2 receptor of our cells and therefore, for the infection.
In their publication, the Chinese researchers explain that the 4A8 antibody targets another epitope. Indeed, the latter recognizes the opposite end of the Spike protein, and not the one usually coming into contact with the ACE2 receptor! And yet, as surprising as it may seem, it is indeed a question of a strong neutralizing power. For scientists, it's all about how 4A8 prevents infection while avoiding blocking the point of contact between the virus and the cell.
The study leaders formulated a hypothesis about the viral protein S. In order to bind to the ACE2 receptor, it must change its conformation several times in space . Without it, it is impossible to get in touch. According to the analyzes of the structures of these proteins, the 4A8 antibody would be capable of preventing the modifications of protein S – and therefore its ability to interact – by attaching itself to its other end.
For Chinese scientists who patented 4A8, the goal now is to improve the effectiveness of treatment. The main interest is to allow to multiply the areas of action and above all, to prevent the virus from surviving and mutating.
