Scientists revealed that, despite their ability to acquire a diverse repertoire of antibodies, humans consistently produce antibodies that target the same viral regions, which may help explain many of the reinfection patterns observed during the COVID-19 pandemic.

Researchers stated that "Public epitopes," or viral protein areas where the antibody recurrently attaches itself, show that a virus may change a single amino acid to reinfect a population of previously immune hosts, according to the researchers. Their findings were reported in the journal Science.

For this study, 569 blood samples were collected from people in France, Peru and the United states. These samples were then analyzed using VirScan, which can identify hundreds of viral epitopes and create a picture of a persons immune history from a single drop of blood.

They determined that identifying public epitopes was a feature of the human antibody response in general.

They identified 376 of these extensively targeted epitopes and determined that antibodies recognized public epitopes via germline-encoded amino acid binding (GRAB) motifs, which belong to sections of antibodies that are particularly competent at selecting a single amino acid.

Human antibodies tend to focus on regions where amino acids are available for binding, allowing the virus to reinfect populations that were previously immune. Experts found an underlying architecture in the immune system that causes people to make the same antibodies that give the virus a small number of targets to evade. This could have implications for treatments against COVID-19, such as monoclonal antibodies, as well as for vaccine design.

 (Source: https://www.tribuneindia.com/news/health/covid-19-human-antibodies-targeting-the-same-viral-protein-regions-could-be-behind-reinfection-495087)