McMaster University researchers have discovered a new way to trap pathogens, such as influenza and SARS-CoV-2 — the virus responsible for COVID-19.
The immunologists say the mechanism acts like a spider web, in which certain white blood cells explode when they bind to these pathogens coated in antibodies. The explosion releases DNA outside of the cell, creating a sticky tangle that acts as a trap.
Researchers at the Hamilton university say the discovery has implications for vaccine design and delivery, including aerosol and nasal spray technologies that could help the body head off infections before they have a chance to take hold.
“Vaccines can produce these antibodies that are present in our lungs, which are the first type of antibody to see viruses like flu or COVID-19, which infect our lungs and respiratory tracts,” says the study’s lead author Matthew Miller, an associate professor at McMaster’s Michael G. DeGroote Institute for Infectious Disease Research. “Mechanisms that can stop the infection at the site where it enters our body can prevent the spread and serious complications.”
By comparison, injectable vaccines are designed to bolster antibodies in the blood. But researchers say those antibodies are not as prevalent at the sites where the infection begins.
“We should be thinking carefully about next-generation COVID-19 vaccines that could be administered in the respiratory tract to stimulate antibodies. We don’t have many candidates right now that are focused on raising the mucosal response,” says Hannah Stacey, a graduate student in the Miller Lab and lead author of the paper, who recently won a major national scholarship from the Canadian Society for Virology for her work on COVID-19.
“If you want a lot of these antibodies that are really abundant in blood, then injections make the most sense, but if you want antibodies that are abundant in the respiratory tract, then a spray or an aerosol makes sense,” she says.
Researchers do caution that while the body’s spider-web mechanism has the potential to be hugely beneficial, it can cause harm too, including inflammation and further illness when the web formation is uncontrollable.
“An immune response that is meant to protect you can end up harming you if it’s not properly controlled,” says Miller, who is also Canada’s Global Nexus for Pandemics and Biological Threats. “It’s important to understand the balance of the immune system. If you have a lot of these antibodies before you get infected, they are likely going to protect you, but if the infection itself stimulates a lot of those antibodies it might be harmful.”
Early in the pandemic, prior to vaccinations, these traps were found in some patients’ lungs, which made their breathing more difficult.
The findings were published online in the Proceedings of the National Academy of Science.