Although catching a cold does not immunize against COVID-19, infection with COVID-19 may, at least temporarily, increase the number of antibodies against the common coronaviruses that cause the common cold, as well as the closely related viruses SARS-CoV-1 and MERS-CoV, according to Science Advances .
The SARS-CoV-2 virus that causes COVID-19 is just one in a large and diverse family of coronaviruses. Several of his relatives are just as contagious and virulent – they caused Middle Eastern Respiratory Syndrome (MERS) and the SARS epidemic in 2002-2004. Others, classified as causing colds, have much milder symptoms.
Many of the human disease-causing coronaviruses have only a quarter to half of the genetic material in common with SARS-CoV-2. However, the individual components of the virus structures – especially the protein of the spines protruding from each coronavirus – are considered relatively similar among members of the family.
Since the start of the COVID-19 pandemic, scientists have wondered does earlier contact with cold viruses affect immunity to SARS-CoV-2and whether COVID-19 infection could change the way the immune system recognizes common coronaviruses. Antibodies directed against one coronavirus spike protein have the potential to recognize other similar proteins as causing the disease as well.
Researchers at the Scripps Research Institute, analyzing antibodies against the SARS-CoV coronavirus in 11 people infected with COVID-19, found more antibodies that recognize other related viruses.
Eight samples were from before the COVID-19 pandemic, ensuring that donors were not exposed to the SARS-CoV-2 viruswhile the three samples were from donors who had recently contracted COVID-19. In each case, the researchers measured how strongly the samples responded to isolated spike proteins from various coronaviruses – OC43 and HKU1, both associated with colds, but also SARS-CoV-1, MERS-CoV, and SARS-CoV-2.
Only serum from COVID-19 patients responded to SARS-CoV-2 spike proteins. However, samples from COVID-19 patients showed a stronger response to other spike proteins than the pre-pandemic samples.
“A better understanding of how resistance to the coronavirus family changes with COVID-19 infection is an important step towards developing better coronavirus vaccines for both COVID-19 and future related pathogens,” said Prof. Andrew Ward, senior study author.
“Most people have basic immunity to common coronaviruses, and exposure to SARS-CoV-2 increases these antibodies,” said Scripps Research PhD student Sandhya Bangaru, first author.
“The ultimate goal would be to rationally design vaccines that can recognize many different coronaviruses,” says Bangaru. “Our results reveal some conserved sites on the S2 subunit that target the antibodies naturally induced during infection that we want to focus on.”
Since the studies were carried out directly on serum antibodies, scientists do not know if the presence of these antibodies in either case is sufficient to provide complete immunity to coronaviruses in the more complex system of the human immune system. Further research is to compare antibodies from the same people before and after COVID-19 infection.
Author: Paweł Wernicki
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