In a new study, researchers have isolated antibodies from several COVID-19 patients that, to date, are among the most potent in neutralizing the SARS-CoV-2 virus.
These antibodies could be produced in large quantities by pharmaceutical companies to treat patients, especially early in the course of infection, and to prevent infection, particularly in the elderly.
The researchers have confirmed that their purified, strongly neutralizing antibodies provide significant protection from SARS-CoV-2 infection in hamsters, and they are planning further studies in other animals and people.
The research was conducted by a team at Columbia University Irving Medical Center.
One of the human body’s major responses to an infection is to produce antibodies—proteins that bind to the invading pathogen to neutralize it and mark it for destruction by cells of the immune system.
Though a number of drugs and vaccines in development for COVID-19 are in clinical trials, they may not be ready for several months.
In the interim, SARS-CoV-2 neutralizing antibodies produced by COVID-19 patients could be used to treat other patients or even prevent infection in people exposed to the virus.
The development and approval of antibodies for use as a treatment usually takes less time than conventional drugs.
This approach is similar to the use of convalescent serum from COVID-19 patients, but potentially more effective.
Convalescent serum contains a variety of antibodies, but because each patient has a different immune response, the antibody-rich plasma used to treat one patient may be vastly different from the plasma given to another, with varying concentrations and strengths of neutralizing antibodies.
When SARS-CoV-2 arrived and led to a pandemic at the beginning of the year, the team rapidly shifted the focus of his HIV/AIDS laboratory to work on the new virus.
The researchers had easy access to blood samples from patients with moderate and severe disease who were treated at Columbia University Irving Medical Center in New York City, the epicenter of the pandemic earlier this year.
They found that although many patients infected with SARS-CoV-2 produce significant quantities of antibodies, the quality of those antibodies varies.
In the patients they studied, those with severe disease requiring mechanical ventilation produced the most potently neutralizing antibodies.
The majority of anti-SARS-CoV-2 antibodies bind to the spike glycoprotein—a feature that gives the virus its corona—on the virus’s surface.
Some of the most potent antibodies were directed to the receptor binding domain (where the virus attaches to human cells), but others were directed to the N-terminal region of the spike protein.
The team found a more diverse variety of antibodies than previous efforts, including new, unique antibodies that were not reported earlier.
These findings show which sites on the viral spike are most vulnerable. Using a cocktail of different antibodies that are directed to different sites in spike will help prevent the virus from becoming resistant to the treatment.
The team says these powerful antibodies are not too difficult for the immune system to generate. This bodes well for vaccine development
Vaccines that elicit strong neutralizing antibodies should provide robust protection against the virus.
One author of the study is David Ho, MD, the scientific director of the Aaron Diamond AIDS Research Center and professor of medicine.
The study is published in Nature.
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