(TND) — Scientists have discovered a protein in the lungs that appears to be a natural defense against the virus that causes COVID-19.
They say this opens up new areas of research and the potential for new treatments.
The protein, leucine-rich repeat-containing protein 15, or LRRC15, binds the virus without passing on the infection, according to researchers at the University of Sydney.
For me, as an immunologist, the fact that there's this natural immune receptor that we didn't know about, that's lining our lungs and blocks and controls virus, that's crazy interesting,” study lead Professor Greg Neely said in a university news release.
The Australian researchers noted that work with the LRRC15 protein has also been taking place at Oxford, Brown and Yale.
Virologist Paula Cannon, who was not involved with this research, says it holds exciting potential as a protection or treatment against COVID-19 and other lung infections.
“What's interesting is these different studies that use different methods and are looking at different things are all coalescing on this molecule as being important,” said Cannon, with the Keck School of Medicine of USC. “So, when you see that, when you see different approaches coming up with the same answer, it lends credibility to the role of this molecule.”
COVID-19 latches onto a receptor to infect us. The docking molecule it latches onto is a protein called the angiotensin-converting enzyme 2, or ACE2.
LRRC15, meanwhile, seems to be behaving like a natural “receptor decoy,” Cannon said.
“It binds to the spike protein. You remember the little red blobs? And when it's bound to the spike protein, it stops the spike protein being able to interact with its natural receptor ACE2,” she said.
Importantly, LRRC15 is a dead-end interaction for the virus, she said.
This natural protective barrier can prevent other vulnerable cells from becoming infected.
University of Sydney researchers called it “molecular Velcro.”
And LRRC15 can work both when it itself is on the surface of a cell, but more importantly, when it's kind of secreted, it's soluble, it's whizzing around in blood and mucous,” Cannon said. “It's there as the way to kind of catch the virus and inactivate it by putting these nonfunctional blocks or locks all over it.”
There’s another potentially important discovery, that LRRC15 could be used to suppress fibrosis, or the damaging scarring that can occur from serious lung infections.
And researchers say there’s evidence that LRRC15 levels may relate to how severe a person’s COVID infection will be. They said the body’s LRRC15 levels seem to increase when a virus is introduced.
The higher the levels, the more effective a person appears to be at fighting off the virus.
Cannon said LRRC15 levels could potentially be used to screen people most at risk for severe infections.
She called the medical uses for the LRRC15 protein “blue sky thinking,” because the science is just emerging. But there are real possibilities to help people, she said.
“There's a potential to develop it as a drug to protect us,” she said. “You could spray it in people's noses or with an inhaler if they're at risk of being infected, and you're giving them a molecule that is a natural antiviral defense.”