Specific antibodies may be effective against multiple coronavirus types

Patients exposed to coronavirus can produce a versatile, cross-reactive coronavirus antibody; this can be useful in the eventual development of a broad-acting vaccine.

There are seven human coronavirus types, four of which cause the common cold, named OC43, HKU1, 229E, and NL63. Most people become infected with at least one of these four coronaviruses at some point in their life. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is another member of the coronavirus family that causes COVID-19. An infection with the cold-causing coronaviruses can lead to an immune memory. This could potentially affect the immune response to COVID-19.

Research published in Nature Communications compared blood samples from patients collected before the pandemic with those who tested positive for COVID-19. In this way, the researchers were able to find types of antibodies that cross-reacted with other coronaviruses and SARS-CoV-2.

Cross-reactive coronavirus antibody produced during SARS-CoV-2 infection

A cross-reactive coronavirus antibody has been discovered to be triggered as a direct result of COVID-19 infection. Dr. Raiees Andrabi, a senior writer on the paper, said, “We have been able to determine that this type of cross-reactive antibody is likely produced by a memory B-cell first exposed to coronavirus, which causes the common cold, and then during COVID -19 infection recalled. "

Memory B cells are long-lived because they can circulate through the body for decades to identify and fight pathogens they have previously encountered. Memory B cells protect against re-infection by quickly producing specific antibodies. Although the study found evidence of pre-existing cross-reactive memory B cells triggered during SARS-CoV-2 infection, there was little evidence of pre-existing cross-reactive SARS-CoV-2 serum antibody samples in prepandemic patients. However, the researchers were able to identify a cross-reactive neutralizing antibody that is specific for the S2 subunit of the spike (S) protein.

How does this antibody work?

The researchers used electron microscopy to visualize how the cross-reactive antibody was able to neutralize a range of coronaviruses, including SARS-CoV-2. They found that the antibody typically binds to the virus' S protein. This range did not seem to vary between different coronavirus strains.

Ge Song, the paper's lead author, stated, “The study underscores the importance of fully understanding the nature of pre-existing immunity, particularly with respect to coronavirus. Previous exposure to a coronavirus, even a virus that causes mild colds, will affect the types and levels of antibodies produced when more serious coronavirus threats emerge. "

Importance of the study

Because immunological memory is the basis of vaccination, the results of this study could potentially lead to the development of a vaccine or antibody treatment that will work against most or all of the coronaviruses. Pre-existing immunity to endemic coronaviruses should be further investigated in order to evaluate antibody responses to SARS-CoV-2.

Co-author Dr. Dennis Burton stated, “Another deadly coronavirus is likely to re-emerge in the future – and if it does, we'd like to be better prepared. Our identification of a cross-reactive antibody against SARS-CoV-2 and the more common coronaviruses is a promising development on the way to a broad-acting vaccine or therapy. "

References:

Song, G. et al. (2021). Cross-reactive serum and memory B-cell reactions to spike protein in SARS-CoV-2 and endemic coronavirus infection. Nature Communications, 12 (1), 1-10. Retrieved from: https://www.nature.com/articles/s41467-021-23074-3

Versatile coronavirus antibody could be the starting point for broader-acting vaccines (2021). EurekAlert! Retrieved from: https://www.eurekalert.org/pub_releases/2021-05/sri-vca052721.php

Quast, I. and Tarlinton, D. (2021). B-Cell Memory: Understanding COVID-19. Immunity, 54 (2), 205-210. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7826135/

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