Researchers have found antibodies in the blood of recovering Covid-19 patients that may protect them against the virus. At least that was the case when they were tested in a small animal model in the lab.
- As the race for the Covid-19 vaccine continues, more and more researchers are looking for antibodies capable of treating the sick.
- American researchers recently found antibodies could block the virus on a hamster in the laboratory.
- If new safety tests on animals and clinical trials on humans go as planned, the antibodies could be used on patients as early as next January.
Currently, manufacturing a treatment or vaccine for Covid-19 is the global public health priority. Today, nearly 8 million people have tested positive for SARS-CoV-2 infection worldwide, and more than 400,000 have died from severe infection with the disease. While the situation is gradually calming down in the West, the daily number of new infections continues to rise in many countries, especially in South America. Recently, researchers discovered antibodies in the blood of recovering Covid patients that may protect against the virus. At least that was the case when they were tested in a small animal model in the lab, scientists reveal today in Science.
The project was led by groups from Scripps Research, IAVI, a non-profit scientific research organization, and the University of California San Diego School of Medicine (USA). Here, researchers took blood samples from patients who had recovered from mild to severe Covid-19. At the same time, other scientists have developed test cells that express ACE2, the receptor that SARS-CoV-2 uses to enter human cells.
The researchers succeeded in isolating more than 1,000 distinct antibody-producing immune cells, called B cells, each of which produces a distinct anti-SARS-CoV-2 antibody. They then obtained the antibody gene sequences from these cells so they could produce the antibodies in the lab. By examining these antibodies individually, they identified several that could block the virus in test cells as well as one that could protect hamsters against heavy viral exposure.
“Promising antibodies for clinical trials”
“The discovery of these very potent antibodies represents an extremely rapid response to an entirely new pathogen.”welcomes the co-author of the study, Dennis Burton, a researcher in the Department of Immunology and Microbiology at Scripps Research.
“We leveraged our institution’s decades of expertise in antibody isolation and quickly focused our efforts on SARS-CoV-2 to identify these very potent antibodies.”adds Elise Landais, co-author of the study and principal scientist of the IAVI.
“It was a huge collaborative effort, and we are now focused on producing large quantities of these promising antibodies for clinical trials.”continues co-lead author Thomas Rogers, assistant professor in the Department of Immunology and Microbiology at Scripps Research, and assistant professor of medicine at the University of San Diego.
A find that will be made available to the most vulnerable?
If new safety tests on animals and clinical trials on humans go as planned, the antibodies, then mass-produced using biotechnological methods, could be used by healthcare professionals as early as next January, say the researchers.
Thus, injections could be given to patients in the early stages of Covid to reduce the level of the virus and protect them against serious illness. What’s more, antibodies could also be used to provide temporary, vaccine-like protection against infection to healthcare workers or vulnerable people (elderly, immunocompromised…). “We intend to make them available to those who need them most, including people in low- and middle-income countries”says Elise Landais.
Finally, another discovery and not the least: during their experiments, the researchers found an antibody capable of isolating SARS-CoV, the coronavirus related to the new one at the origin of the outbreak of severe acute respiratory syndrome (SARS) in the early 2000s in Asia. “This discovery gives us hope that we will eventually find broadly neutralizing antibodies that offer at least partial protection against all or most SARS coronaviruses, which should be helpful if another jumps on the man”concludes Dennis Burton.
An increasingly explored approach
Antibodies are an approach increasingly explored by scientists to protect patients from new viral threats. This has already been used successfully against the Ebola virus and the pneumonia-causing respiratory syncytial virus, commonly known as RSV, in particular.
Against Covid-19, this approach is currently being tested by many other researchers. At the end of May, a Swiss-American team revealed in the review Nature having discovered an antibody “promising” against SARS-CoV-2. This antibodyholds the promise of an effective antidote to limit the Covid-19 pandemic”, believe the researchers. The combination of S309 and two other antibodies could “mitigate the risk” of the emergence of viral resistance against this type of treatment. “Our data indicate the potential discovery of potently neutralizing monoclonal antibodies against sarbecoviruses (…) and sets the stage for a better response” in the event of new epidemics caused by this type of virus, conclude the researchers.
In the United States, the American group Eli Lilly announced last week that it had started testing two specific therapies against the coronavirus based on antibodies on patients. If the trials go as planned, the treatments could be marketed as early as the fall, well before the arrival of a vaccine, not expected before 2021 despite the efforts of the hundred laboratories on the spot.
What about vaccines?
Remember that today, 95 vaccines are still in the running and the first clinical trials on humans are starting around the world. A Chinese laboratory has just started the second phase of clinical trials, which involves humans, to find a vaccine against the coronavirus. The Institut Pasteur will have the first results in October to find out if its vaccine, based on a modification of the one used against measles, is effective against Covid-19.
In Europe, the hope of a vaccine rests above all on the British laboratory AstraZeneca, which works with the University of Oxford (United Kingdom). The project is “based on viral vectordescribes Olivier Nataf, president of AstraZeneca France, to France info. You take a virus that is inactivated, we change its genetic code to insert the genetic code that will make it possible to produce the coronavirus protein. By producing this protein, the patient will be able to develop an immune response against the characteristic protein of the coronavirus.“It is currently being tested on several thousand patients in the UK, Brazil and the US, where the virus is still circulating very actively. “The studies we are currently conducting will allow us to have results in the fall”, promises Olivier Nataf.
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