Antibodies in COVID-19 Survivors Confirmed Potent in Protecting Cells from Infection: Study
Fri, December 3, 2021

Antibodies in COVID-19 Survivors Confirmed Potent in Protecting Cells from Infection: Study


A new study revealed antibodies from COVID-19 survivors could provide high protection against SARS-CoV-2. The protection was determined in lab tests conducted in animal and human cell cultures.

The study of antibodies with a high protective effect against COVID-19 was led by scientists at Scripps Research, an American nonprofit medical research facility. Their findings showed that antibodies from those who recovered could protect cells from the SARS-CoV-2 virus, according to lab experiments. In principle, transfusing these antibodies in patients who are in the early stages of the disease could be protected. The same thing could be done to protect medical frontliners consistently exposed to the virus. They published the results in the journal Science.

Powerful Antibodies Could Neutralize Novel Coronavirus

While vaccine research for COVID-19 is ongoing, other scientific studies are dedicated to confirming the efficacy of existing therapies. This is one way to flatten the curve of outbreaks in cities. One of the existing treatments used in clinical settings is convalescent plasma therapy. This treatment transfuses antibodies from a person who recovered to a sick individual. It has been applied in various illnesses, including influenza and severe acute respiratory syndrome or SARS. Though, no one knows how much help this therapy can be per person.

At Scripps Research, scientists tested antibodies from COVID-19 survivors in cell cultures and animal models. Their experiments highlighted the protective effect of these proteins. The protective effect represented the efficacy of antibodies in treating and preventing SARS-CoV-2, the novel coronavirus. In the context of prevention, the antibodies could be utilized as a precautionary measure for patients who developed mild symptoms and for healthcare workers. The use of the antibodies in the early stages of the disease might be as optimal as its application in patients with severe symptoms.

"It has been a tremendous collaborative effort, and we're now focused on making large quantities of these promising antibodies for clinical trials," said Dr. Thomas Rogers, a lead author of the study and assistant professor in the Department of Immunology and Microbiology at Scripps.

The development of a specific treatment or an effective vaccine is still the main priority in defeating this pandemic. But creating just one takes a long time: from research to clinical trials. Thus, other avenues that can help patients and the global healthcare system are required until a functional drug is created. For now, antibodies are the best angle to explore to treat patients. So, experiments are required to make it reliable and scalable at the same time.



In the study, the team recruited 17 people previously infected by COVID-19. These individuals were recruited in San Diego, California. Around 47% of the participants were female and the average age of everyone was 50 years. The polymerase chain reaction (PCR) test was used to confirm the infection of the participants. Their symptoms during infection ranged from mild to severe and were found to be consistent with the new disease.

Blood samples were collected from the participants and were tested in the lab. The experiments for the blood samples involved animal and human cell cultures engineered to express the ACE2 protein, the primary requirement of SARS-CoV-2 to infect and hijack, and select animal models. Scientists tested if the antibodies from the blood donors could bind to the virus. They examined as well how strong the binding was in protecting cells

During the experiments, B cells – a type of white blood cell – were identified in the blood samples. Over 1,000 unique B cells capable of producing antibodies were isolated in the process. Next, antibody gene sequences from B cells were obtained to enable synthetic production in the lab. Then, they screened every antibody to assess individual strength against the deadly virus. Results showed that all antibodies designed to bind SARS-CoV-2 could protect cell cultures. Though, one of the antibodies was identified with a superior protective effect than others.

The superior antibody even shielded a hamster from heavy exposure of SARS-CoV-2. That antibody and the others were also tested against a former health threat: SARS. Experiments on SARS-CoV showed that the antibodies generated for SARS-CoV-2 worked normally, meaning the antibodies could protect a person from SARS and COVID-19. However, the team could not confirm immunity from both illnesses at this time.

Because they were able to isolate the antibodies, scientists could develop them in mass quantities. If the idea came to fruition, antibody transfusion for COVID-19 patients and medical frontliners would be easier and more convenient to do. Today, plasma therapy depends on the availability of plasma from donors. This limits the supply of therapeutic plasma for everyone.

Furthermore, any success in producing massive volumes of antibodies in the lab can aid territories affected by other viral diseases. The synthetic manufacturing of vaccine-like therapy can assist multiple global health responses crippled by the pandemic.



The General Efficacy of Plasma Therapy

On April 14, 2020, a study published in Erciyes Medical Journal showed the overall efficacy of plasma therapy in multiple illnesses. The authors noted the historical implications of the therapy since the 1890s. Plasma therapy has been used to treat the Spanish influenza A H1N1, avian influenza A H5N1, the Middle East Respiratory Syndrome, SARS, hepatitis, rabies, polio, meningitis, pneumococcal pneumonia, Ebola virus disease, 2009 influenza A H1N1, mumps, and measles. The majority of these illnesses are caused by viruses.

Using historical data, the authors examined the impact of plasma therapy on viral infections. For the Spanish flu, which killed millions worldwide, 1,703 patients with Spanish influenza and pneumonia were treated with plasma products. A significant decline in fatality was confirmed. The maximum benefit from the therapy could be achieved by giving the plasma within 48 hours after pneumonia develops. The reduction in fatality risk was calculated between 18.66% and 21.6%.

For SARS, a meta-analysis of 32 trials showed a significant decline in fatality. The administration of plasma therapy could lead to an absolute reduction of fatality risk between 7% and 23%, while the release from the hospital on day 22 was 54% higher in those who were treated with plasma. Across all available data, the majority of plasma therapy recipients experienced no adverse reactions. Though, rare cases of adverse events, such as anaphylaxis and serum sickness, were reported.

Antibodies from COVID-19 survivors are a life-saver for patients in critical condition. If scientists can produce them in massive quantities via biotechnology, more patients of COVID-19 can be administered with plasma therapy. Doctors no longer have to wait for patients to become very ill to give such treatment.