Dr. Mario Ostrowski is using antibodies from recovered patients to neutralize the virus.
There’s still a lot we don’t know about the COVID-19 virus wreaking havoc on the world right now, but our scientists are working relentlessly on ways to understand and defeat it. Dr. Mario Ostrowski, an infectious disease physician at St. Michael’s Hospital, normally specializes in studying immune responses to HIV and Hepatitis C. But now, in the midst of the COVID-19 pandemic, he is leading an international effort to develop therapies using antibodies from patients who have recovered from the disease.
Dr. Ostrowski and his team are collecting blood cells for the study using a procedure called leukapheresis, in which a patient is hooked up to a machine that gathers a massive number of cells and then returns their blood to them. “In order to really intensively study the immune response against a pathogen like COVID-19, you need large numbers of immune cells, much more than you can get in a regular blood draw,” he explains. “So leukapheresis is a very valuable resource.”
While a regular blood sample might allow researchers to do one or two experiments, one two-hour leukapheresis procedure provides billions of immune cells, meaning one person can contribute to multiple COVID-19 research projects around the world. And that is enabling some exciting collaborations and even leading to breakthroughs. Dr. Ostrowski sent one patient’s sample to a U.S. investigator, James Crowe, at Vanderbilt Medical Center, who was able to identify cells making antibodies that can neutralize the virus. “In a couple of months he’ll be able to synthesize that antibody in large amounts and create a therapeutic that could stop the virus from replicating in sick patients,” he says.
Another collaboration involves immunologists teaming up with structural biologists to determine exactly where on the virus the antibodies are binding. “If we can do that,” says Dr. Ostrowski, “vaccine companies can use that region of the virus rather than other parts that might not work. This study will help the vaccine community make a proper vaccine.”
Dr. Ostrowski cautions that it will take time to produce an effective vaccine for COVID-19. “There are a number of vaccine trials going on right now,” he says. “We’re working with a vaccine company here in Toronto that should be ready to start clinical trials in September. The most important thing is safety, of course, because vaccines are given widely, and we need to make sure the vaccines won’t cause side effects or make the disease worse. It’s especially important with this virus, because we still don’t know too much about it.” That includes how quickly it’s mutating, how long recovered patients might be immune, and whether the antibodies will work on other strains of the virus.
Still, Dr. Ostrowski is optimistic. “It’s really exciting to see how fast the world is responding to this pathogen,” he says. “Everyone wants to solve this problem together.”