A new study from UCLA shows that a viral protein other than the well-known spike protein may play an important role in severe COVID-19 and possibly even long-term COVID. The protein, called the nucleocapsid protein, is found inside the virus and is responsible for protecting its genetic material.
The researchers discovered that this protein affects the immune system in two opposite ways. Early in the infection, it suppresses the body’s antiviral defenses, which helps the virus establish itself. At the same time, it can later overactivate immune cells called macrophages. These release large amounts of inflammatory signaling substances, which can lead to severe inflammation and damage to the body’s tissues.
In laboratory experiments, the researchers saw that the severe inflammation caused the protective barriers of the blood vessels to become more permeable, especially in models of the blood vessels of the heart. This could help explain why some people with COVID-19 suffer from heart problems and other complications. The variant of the virus that had the strongest inflammatory effect was the delta variant.
The researchers believe that the results may help explain some of the long-term complications seen after COVID-19, where persistent overactive inflammation is thought to play an important role. They also believe that future treatments or vaccines that target the nucleocapsid protein, rather than just the spike protein, could reduce harmful inflammation more specifically and thereby protect, among other things, the heart and blood vessels.
The study was conducted on cell models in the laboratory and shows a possible biological mechanism. It does not prove that this alone causes long-term COVID in humans, but provides a new and important piece of the puzzle in understanding how SARS-CoV-2 can cause long-term symptoms.
Credit: Explaining text by Patrik Andersson (Facebook group “SARS-CoV-2 Omvärldsbevakning”)
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A lesser-known SARS-CoV-2 protein may offer clues to long COVID symptoms
A new study from UCLA shows that a viral protein other than the well-known spike protein may play an important role in severe COVID-19 and possibly even long-term COVID.
