;Resize=(1200,627)&impolicy=perceptual&quality=medium&hash=6a377bf2643dc2b7cafeb42d6735ba1c7ea5e66a6c473e202d9e84ca7d19bedb "Researchers find virus markers that decide whether the corona’s course is severe")
Alpha, beta, gamma, delta and now omicron – the list of coronavirus variants continues to grow. Some spread more widely and make infected people more seriously ill. But why?
The role of the spike protein has long been known. The so-called “spiny protein”, which gives the coronvirus its appearance, binds to the ACE2 receptors in our cells. This allows the pathogen to enter the cells and multiply there. This is where our corona vaccines come into play. They stimulate our immune system to defend itself against the spike protein.
Researchers find virus markers that decide whether the corona’s course is severe
But does the spike protein also play a role in the severity of the course? In a new study, researchers led by Matthew Frieman of the University of Maryland School of Medicine found that both the spike protein and the so-called accessory proteins of Sars-Cov-2 have an influence on the severity of corona disease. “They target our immune system and contribute to the violence with which the body reacts to a Covid 19 infection,” the university’s statement said Friday. The results of the study were published in the journal Proceedings of the National Academy of Science (
PNAS
) released.
First, the researchers looked at the currently predominant omicron variants BA.4 and BA.5. Both variants have mutations in the spike protein. “The interesting thing is that both the BA.4 and BA.5 variants share the same genetic sequence for the spike protein,” Frieman said. ‘That means it’s the other genes, the non-spike protein genes, that influence how the virus copies itself and causes disease.’ In particular, “mutations in accessory genes”.
ORF3a / b and ORF8 play a role
For their study, the scientists designed viruses without the accessory genes and then infected the mice with these new viruses or the original virus. The research team found this out
-
virus that
ORF3a / b-Gen
he was missing too
milder infections
carried -
virus that
ORF8 gene
he was missing too
more serious infections
carried
According to the researchers, mutations in the ORF8 gene in particular play a role, as ORF8 apparently controls the immune response in the lungs. “By inhibiting the immune response, ORF8 helps the virus replicate more in the lungs, making the infection worse. If it is removed, the immune system can react more severely, ”says Frieman.
The Spike protein determines gravity in some, but not all, variants
The researchers then examined how important the spike protein was for disease severity in the different variants of the corona. To do this, they took the original virus and replaced the spike gene with the spike gene of the alpha, beta, gamma or delta variant.
The result: the spike protein determined the severity of some, but not all, variants. For example, the gamma variant was weaker than the others. Researchers suspect that mutations in genes outside the “peak”, particularly in the ORF8 gene, play a role in this variant being weaker than the others.
New Biomarkers Discovered – Are New Vaccines Coming?
What does this mean in particular? The severity of the disease course in individual corona variants is influenced by the spike protein. But that’s not all: the study shows that so-called accessory genes can also play a role. Scientists were able to demonstrate this using ORF8 and ORF3a / b.
They assume that accessory protein genes, including mutations, will play an increasingly important role. This discovery could also play a role “in the development of future vaccines or new treatments,” the university’s statement said. They require further research on accessory genes. You yourself want to focus on further decoding the function of ORF8 in future studies.
