British scientists report in the latest issue of the Journal of infectious diseases of the American Chemical Society. Their research shows that infection of two different common human coronaviruses does not produce antibodies that can react effectively with COVID-19. Therefore, previous infection with common coronavirus is unlikely to antagonize or aggravate COVID-19 infection. Although COVID-19 has swept the globe, it is not the only coronavirus that can infect humans. However, unlike COVID-19, infection with common human coronavirus (HCOV) usually has mild symptoms. Because of the obvious genetic sequence similarity between COVID-19 and its common human coronavirus "near relatives", the researchers wanted to find out whether the immune system could identify new coronavirus from the common human coronavirus before infection. If so, it is possible to reactivate the memory B cells, making them produce antibodies and help people fight COVID-19. On the other hand, if antibodies to the common human coronavirus can recognize COVID-19, but not enough to produce an immune response, it may lead to antibody dependent enhancement (ADE) - the antibody produced by virus infection is non neutralization or weak neutralization, which promotes the entry and infection of host cells, resulting in increased infectivity and virulence. To this end, in the latest research, Tuomas Norris, Professor of Biophysics and Biophysics chemistry at University of Cambridge, and his colleagues hope to compare the strength and concentration of human common coronavirus and COVID-19 antibody detected in 9 serum recovered from COVID-19 and 3 serum collected before the outbreak of COVID-19. To this end, the research team used an analytical technology called "microfluidic antibody affinity". Unlike the traditional enzyme-linked immunosorbent assay (ELISA), the new technology can independently detect antibody affinity and concentration. As a result, Norris and others found that all the serum of COVID-19 recovered patients contained a moderate number of antibodies which had high affinity for COVID-19 spike protein. In contrast, the serum collected before the outbreak of COVID-19 did not contain high affinity antibodies to COVID-19. All 12 sera contained low levels of high affinity antibodies against two common human coronaviruses, indicating that the owner of the serum had previously been infected with human common coronavirus. Other experiments showed that these antibodies did not bind to COVID-19. The researchers said that the results showed that there was no obvious cross reaction between antibodies against common human coronavirus and antibodies against COVID-19. Therefore, previous infection with common coronavirus was unlikely to antagonize or aggravate COVID-19 infection. (Xinhua News Agency)