A team of researchers in the US have found that exposure to the SARS-CoV-2 spike protein alone was enough to induce Covid-19-like symptoms, including severe inflammation of the lungs.
SARS-CoV-2, the virus that causes Covid-19, is covered in tiny spike proteins. These proteins bind with receptors on our cells, starting a process that allows the virus to release its genetic material into a healthy cell.
The researchers from Old Dominion University, Virginia, US, developed a genetically modified mouse and injected it with a segment of the spike protein and analysed their response 72 hours later. Another group of mice received only saline to serve as control.
The genetically modified mice 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. However, the mice that only received saline remained normal, the results showed.
"Our findings show that the SARS-CoV2 spike protein causes lung injury even without the presence of intact virus," said Pavel Solopov, Assistant Professor at the varsity.
"This previously unknown mechanism could cause symptoms before substantial viral replication occurs," Solopov said.
The findings will be presented at the American Society for Pharmacology and Experimental Therapeutics annual meeting during the virtual Experimental Biology 2021 meeting, to be held April 27-30.