Immune response, not acute viral infections, responsible for neurological damage, McMaster researchers discover

Feb. 20, 2024
The discovery offers researchers and scientists a new target for treatments of neurological diseases sparked by acute viral infections.

For years, there has been a long-held belief that acute viral infections like Zika or COVID-19 are directly responsible for neurological damage, but researchers from McMaster University have now discovered that it’s the immune system’s response that is behind it.

The research, published on Feb. 5, 2024 in Nature Communications, was led by Elizabeth Balint, a PhD student at McMaster, and Ali Ashkar, a professor with the Department of Medicine and the Canada Research Chair in Natural Immunity and NK Cell Function.

To come to this conclusion, the McMaster team focused on Zika virus. During laboratory testing, researchers, as expected, found T cells that were specific for Zika and designed to eliminate infected cells. They found something else, too.

“What was interesting in our study is that although we did find some T cells specific for Zika, we identified cells that weren’t functioning like a normal T cell and were killing lots of cells that weren’t infected with Zika."

These cells are called NKG2D+CD8+ T cells and researchers say their aggressive response is responsible for neurological damage suffered from infections beyond just Zika, like COVID-19 and even septic shock.

The aggressive response is the result of the body producing large amounts of inflammatory proteins called cytokines, which in moderation help to coordinate the body’s response in battling an infection or injury by telling immune cells where to go and what to do when they arrive.

"If our body’s immune cells overreact and over produce inflammatory cytokines, this condition will lead to non-specific activation of our immune cells which in turn leads to collateral damage. This can have severe consequences if it happens in the brain,” Ashkar says.

McMaster University release on Newswise