COVID-19 virus protein triggers immune attack on healthy cells: study

________________

Israeli researchers have discovered that a protein from the SARS-CoV-2 virus, responsible for COVID-19, can cause the immune system to attack healthy cells mistakenly, the Hebrew University of Jerusalem said in a statement on Tuesday.

The study, published in Cell Reports, sheds light on how severe COVID-19 complications may occur and suggests new ways to prevent immune-driven damage from the virus.

The researchers found that the virus's nucleocapsid protein (NP), which normally helps package the virus's genetic material inside infected cells, can spread to nearby uninfected epithelial cells.

Once on the surface of these healthy cells, NP would be mistakenly identified by the immune system as a threat. The immune system then deploys anti-NP antibodies, which mark these uninfected cells for destruction.

The process triggers the classical complement pathway, a part of the immune response that leads to inflammation and tissue damage, contributing to severe COVID-19 symptoms and possibly long COVID.

Using lab-grown cells, advanced imaging, and samples from COVID-19 patients, the researchers found that NP binds to a type of molecule on cell surfaces. The binding causes the protein to cluster on healthy cells, further confusing the immune system.

The study also found that the drug enoxaparin, a common blood thinner and heparin analog, blocks NP from sticking to healthy cells. In both lab tests and patient samples, enoxaparin helped prevent immune attacks by occupying the binding sites that NP uses.

According to the researchers, the discovery may offer new hope for reducing immune-related complications in COVID-19 and potentially other viral infections.