Type I interferon prevents the immune system from “going rogue” during viral infections

Newswise — Hamilton, ON (May 17, 2022) — Researchers at McMaster University have discovered not only how certain viral infections cause severe tissue damage, but also how to reduce that damage.

They discovered how type I interferon (IFN) prevents the immune system from “going rogue” and attacking the body’s own tissues when fighting viral infections, including COVID-19.

Their paper was published today in the journal PLOS Pathogens.

Lead author Ali Ashkar said IFN is a well-known antiviral signaling molecule released by cells in the body that can trigger a powerful immune response against harmful viruses.

“What we found is that it’s also critical in preventing white blood cells from releasing protease enzymes, which can damage organic tissue. It has this unique dual function to trigger an immune response against a viral infection. on the one hand, as well as to restrict that same response to avoid significant tissue damage to bystanders on the other,” he said.

The research team studied the ability of IFN to regulate a potentially dangerous immune response by testing it against both influenza and the HSV-2 virus, a very common sexually transmitted pathogen, using mice. Data from COVID-19 patients in Germany, including post-mortem lung samples, were also used in the study.

“For many viral infections, it’s not actually the virus that’s causing most of the tissue damage, it’s our heightened immune activation against the virus,” said Ashkar, a professor of medicine at McMaster.

The study’s first co-author and PhD student, Emily Feng, said: “Our body’s immune response tries to fight off the viral infection, but there is a risk of damaging innocent healthy tissue in the process. IFNs regulate the immune response only to target tissues that are infected.

“By uncovering the mechanisms used by the immune system that can cause inadvertent tissue damage, we can intervene during infection to prevent that damage and not necessarily wait for vaccines to be developed to develop life-saving treatments,” he said. -she adds.

“This applies not only to COVID-19, but also to other highly infectious viruses such as influenza and Ebola, which can cause extensive and often fatal damage to organs in the body,” said the first co-author. of the study, Amanda Lee, specialist in family medicine. resident.

Ashkar said the release of harmful proteases is the result of a “cytokine storm,” which is life-threatening inflammation sometimes triggered by viral infections. It has been a common cause of death in patients with COVID-19, but a treatment has been developed to prevent and suppress the cytokine storm.

Ashkar said steroids like dexamethasone are already being used to curb an extreme immune response to viral infections. The authors used doxycycline in their study, an antibiotic used for bacterial infections and as an anti-inflammatory agent, inhibits the function of proteases causing tissue damage.

Lee added, “This has the potential to be used in the future to blunt life-threatening virus-induced inflammation and warrants further research.”

The study was funded by the Canadian Institutes of Health Research.

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Publishers:

Photos of Ali Ashkar and Emily Feng are available at https://bit.ly/3wmSw0D

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