Covid-19: Chinese researchers discover new surprisingly effective coronavirus antibody

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Chinese researchers have recently been working on a new antibody from a dozen coronavirus patients. If the latter has a strong neutralizing power, the target is not the same as that usually targeted by other antibodies!

A special antibody

At the end of May 2020, we reported on a research carried out in Taiwan. Scientists had then discovered a monoclonal antibody capable of preventing the SARS-CoV-2 virus (Covid-19) from entering the human body. There was talk of a virus inhibition capacity ranging from 90% to 98%.

A study piloted 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 people healed from the disease, this antibody named 4A8 has a strong neutralizing power according to the researchers. However, this antibody is special insofar as it attacks another part of the protein responsible for the infection!

Surprisingly effective

Inoculating a vaccine entails the presence of a harmless version of a microorganism. This makes it possible to produce numerous antibodies to combat the undesirable microorganism. Thus, antibodies attach 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), which is responsible for the interaction with the ACE2 receptor in our cells and therefore for 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, the key is how 4A8 prevents infection while avoiding blocking the point of contact between the virus and the cell.

The study leaders formulated a hypothesis concerning the viral protein S. In order to bind to the ACE2 receptor, it must change conformation several times in space. Without that, it’s impossible to get in touch. According to analyzes of the structures of these proteins, the 4A8 antibody is capable of preventing modifications of protein S – and therefore its ability to interact – by attaching itself to its other end.

For the Chinese scientists who patented 4A8, the goal now is to improve the effectiveness of the treatment. The main interest is to multiply the areas of action and above all, to prevent the virus from surviving and mutating.

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