Scientists have come up with a new way to get vaccinated against the coronavirus that causes COVID-19, and it comes with a twist: No needles are needed.
Rather, this vaccine would be aerosolized so that it could be inhaled by a patient.
The researchers tested this vaccination strategy in mice and it elicited a strong immune response. A team led by researchers from Northeastern University, Rice University and Rutgers University published a proof of concept study in the review Proceedings of the National Academy of Sciences this week. The project is still in its early stages, but the team sees the vaccine they are developing as a way to expand the reach of COVID-19 vaccines around the world.
“If we can have this new tool, that would be great. It’s easy to produce, easy to ship, easy to administer, ”says Paul Whitford, associate professor of physics at Northeastern and author of the new paper. Such an inhalable COVID-19 vaccine would not require precise refrigeration of existing inoculations and could be more easily dispersed in rural and remote communities. “You just need basic instructions on how to use an inhaler.”
The team’s vaccine strategy uses modified bacteriophage particles to deliver instructions to the immune system – via the lungs – to develop a protective response to SARS-CoV-2, the coronavirus that causes COVID-19.
Bacteriophage particles (or phage particles for short) are viruses that infect bacteria but are harmless to humans and have been used to treat bacterial infections in humans for a century.
In this new vaccine strategy, a phage particle in the immunizing mist is much like a visitor knocking on the door of lung tissue. He has an outstretched arm to accommodate lung tissue and a backpack full of immune instructions on his back, explains Whitford.
The phage particles have been engineered to contain a protein (the metaphorical arm) that lung cells will recognize and attract into the recipient’s bloodstream. “You have to reach out and say, ‘Let me in! “, He said. “And then, ‘Okay, I have something for you.'”
This “something” is a precious cargo: tiny pieces of the SARS-CoV-2 spike protein. But it’s not just any song. This is called an “epitope”. This is the part of the invasive protein where an antibody can attach itself to the offending viral cell to prevent it from infecting one of our cells.
The idea is to pass these parts of the virus to the body’s immune system to give it some sort of practice to fight SARS-CoV-2. That way, says Whitford, if you’re exposed to the real virus, your immune system will know what to do immediately.
But there is a wrinkle. The spike protein contains many different epitopes. And some of them lose their shape (and therefore their properties) when you remove them from the rest of the virus.
Whitford and his colleagues from Center for Theoretical Biological Physics, hosted in both Northeastern and Rice, turned to supercomputers. The team performed simulations of what would happen when certain selected epitopes were transferred to a phage. Their analysis identified which epitope would retain its structure and best train the immune system to attack the true SARS-CoV-2. Then Rutgers’ experimental team developed the vaccine and tested it on mice.
“Practically, experimentally, you can’t make a thousand candidate vaccines and test them all just to see which one works,” says Whitford. “You cannot use this lots of mice just to see if that will work.
The recently published study is largely preliminary, as there are many other epitope candidates that the team has yet to examine. Sorting out all the possible configurations using supercomputers is the next step, says Whitford. “This study provides a kind of proof of principle that this is a decent strategy,” he says. “It was our first visit.”
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