New monoclonal antibody designed to neutralize SARS-CoV-2

As the coronavirus pandemic continues to spread, scientists are racing to find a way to combat the disease. Research teams and pharmaceutical companies around the world are still searching for a vaccine or a drug to prevent or treat COVID-19.

One of the findings that is shaping up to be promising is monoclonal antibody therapy, a type of drug that can be used both to prevent infection and to treat it once the disease has developed.

What are monoclonal antibodies?

When the body detects the presence of an antigen, in this case SARS-CoV-2, the immune system produces antibodies, proteins designed to neutralize that particular antigen, with the aim of preventing it from penetrating our cells, hijacking their mechanism, and reproducing.

“Monoclonal antibodies (mAbs) are synthetic copies created in the laboratory from a clone of a specific antibody found in the blood of a person who has recovered from COVID-19.” In other words, mAbs mimic the antibodies that our body produces naturally.

These antibodies are distilled from the blood of patients who have recovered from COVID-19. Ideally, they are injected in the early stages of the infection (or even before exposure, as a preventative measure) to provide rapid immunity.

Unlike a vaccine, which introduces a protein or genetic material into our body to stimulate the immune system (to generate antibodies), these are antibodies that are supplied to the body to provide protection.

The journal Science has published a promising finding by the team led by Laura M. Walker, from the American pharmaceutical company Adimab, which has managed to design a new antibody that has already been tested in mice and is capable of preventing SARS-CoV-2 , the virus that causes Covid-19 .

In the study: Broad and potent activity against SARS-like viruses by an engineered human monoclonal antibody , the team describes "an engineered antibody (which they have named ADG-2 ) that neutralizes SARS-CoV-2 with a potency that rivals current clinical, 'broadly neutralizing' SARS-CoV-2 antibodies, but also broadly neutralizes other coronaviruses and provides significant protection against SARS and COVID-19 disease in mouse models."

According to the study, in mice treated with ADG-2, coronavirus infection was slowed, and when applied to already infected rodents, this antibody was shown to help lower the viral load. It also demonstrated " complete protection against respiratory load, viral replication in the lungs, and pulmonary pathology . " Therefore, ADG-2 represents a "promising candidate for the prevention and treatment not only of COVID-19, but also of future respiratory diseases caused by emerging coronaviruses."

How important are monoclonal antibodies for the prevention of Covid-19?

Monoclonal antibodies are important for reasons such as the following:

1. They can serve as another prevention option, in case a vaccine is not available.
2. They can provide immediate protection for those who are exposed and have not yet been vaccinated.
3. They may be necessary for people who cannot develop or maintain an immune response after vaccination, such as older adults.

The FDA, the United States health agency, granted emergency use authorization for these therapies because they have been found to protect high-risk patients from hospitalization and death. However, perhaps one of the drawbacks is that the treatment is very expensive and not accessible to everyone.

Ramona Ávila Núñez, PhD

Reference:

Rappazzo CG, Tse LV, Kaku CI et al. Broad and potent activity against SARS-like viruses by an engineered human monoclonal antibody. Science . 2021 Feb 19;371(6531):823-829. doi: 10.1126/science.abf4830. Epub 2021 Jan 25. PMID: 33495307; PMCID: PMC7963221.