“Our findings show that the SARS-CoV2 spike protein causes lung injury even without the presence of intact virus,” said Pavel Solopov, Ph.D., DVM, research assistant professor at the Frank Reidy Research Center for Bioelectrics at Old Dominion University. “This previously unknown mechanism could cause symptoms before substantial viral replication occurs.”
The researchers found that the genetically modified mice injected with the spike protein exhibited COVID-19-like symptoms that included severe inflammation, an influx of white blood cells into their lungs and evidence of a cytokine storm—an immune response in which the body starts to attack its own cells and tissues rather than just fighting off the virus. The mice that only received saline remained normal.
https://medicalxpress.com/news/2021-04-sars-cov-spike-protein-lung.html