Antibodies: What are they and how are they used in COVID-19 research and treatment?
Early on in the COVID-19 pandemic, the term “antibodies” was tucked into the various conversations about vaccines and treatment options that swirled through public and scientific communities alike. Could they help treat the sick? When could they be retrieved from recovered COVID-19 patients? How should they be administered? The conversations and possibilities often outpaced the explanations.
As global research efforts continue looking at a variety of treatment and preventative options, we are seeing more antibody trials coming online — including here through Baylor Scott & White Research Institute.
What are antibodies?
Antibodies are like foot soldiers within the immune system. They are proteins made by the body in response to an infection to help slow it down or stop it. They seek out invaders and can tag the infection so that the body knows what to fight, or they can latch onto it and help shut down the infectious agent entirely by preventing it from replicating or invading more cells.
The human body can eventually produce specific antibodies to COVID-19 but because this is a new virus, it takes the body more time. For COVID-19, it takes an average of 14 days or longer to start making these antibodies, during which time the virus continues to replicate and grow.
How are antibodies being used for COVID-19?
Researchers are using antibodies created within the bodies of individuals who have recovered from COVID-19 to find ways to “re-deploy” these foot soldiers.
While finding effective vaccines will help healthy people to produce their own antibodies without contracting COVID-19, for patients who are already infected and suffering from the disease, these antibody trials have become a heavy focus in the research community.
Some studies take an offensive approach and seek to use antibodies to create vaccines and other ways to prevent infection entirely. Other trials cover a defensive plan by focusing on treatment options for people who are already sick.
Convalescent plasma (plasma from patients who have recovered from COVID-19) is one example of a defensive plan. All of the different antibodies that someone who has recovered from COVID-19 has produced are retrieved, then infused in a sick patient to try and help boost their own immune system.
Other treatment options being explored use only specific antibodies from recovered patients to target specific portions of the virus. Baylor Scott & White Research Institute is also involved in studies that take this approach, including a trial specifically targeting the mechanism that enables COVID-19 to reproduce and grow in infected patients.
How does the clinical trial work?
COVID-19 grows by using some of the proteins on its surface (called spike proteins) to attach to human cells, setting off an infection.
This trial uses specific monoclonal “Anti-Spike” antibodies to bind to the spike protein of COVID-19 cells in the body to prevent them from attaching to other human cells. The trial combines two monoclonal antibodies that concurrently attach to two areas on the receptor binding portion of the spike protein.
“By preventing the virus from attaching to other cells in the body, we are essentially shutting down the virus growth,” said Mezgebe Berhe, MD, an infectious disease specialist and principal investigator for the trial at Baylor Scott & White. “For this reason, they’re called neutralizing antibodies.”
Dr. Berhe, whose team enrolled the first patient in the U.S. on this trial, said the institution is participating in a variety of clinical trials for patients who have COVID-19.
While many clinical trials to date have used medications that have been used for other conditions (essentially repurposing existing medications), the Anti-Spike trial from Regeneron is among those that are newly created to specifically target the spike proteins with the intent of neutralizing the virus that causes COVID-19.
The use of monoclonal antibodies to fight different diseases and infections is not new. Monoclonal antibodies have been used to treat conditions like inflammatory diseases and cancers, among others. The difference in application with these other diseases versus the Anti-Spike trial is that the monoclonal antibodies with these other indications target human tissue. With Anti-Spike, the target is a part of the virus itself.
The study is categorized as randomized, double-blind, placebo-controlled. That means that patients who pass the pre-trial screening and are enrolled will be randomized to receive either a placebo or one of the different indicated doses of the Anti-Spike monoclonal antibody infusion. Double-blind means that neither the participant nor the research team will know which option the participant receives. This type of trial design helps determine if an intervention produces the intended results and define its safety.
Enrollment on the study is currently open with screening for potential candidates being conducted by Baylor Scott & White Research Institute staff.
Dr. Berhe has been with Baylor Scott & White for 16 years and worked with HIV and a host of other infectious diseases during his career, but he said the last 4-5 months dealing with COVID-19 have been the most challenging.
“It’s not just 1% or some segment of the population that is getting sick,” he said. “That is why these various clinical trials we are involved with are so important. We need to explore this problem from different angles and understand all of our options.”
Learn more about ongoing research efforts through Baylor Scott & White Research Institute.
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