Pre-existing coronavirus antibodies could help protect children against new pandemic strain

November 06, 2020

Researchers at the Francis Crick Institute and University College London have found that some antibodies, created by the immune system during infection with common cold coronaviruses, can also target SARS-CoV-2 and may confer a degree of protection against the new viral strain.

In response to infection with a virus, the immune system creates antibodies to help fight it. These antibodies remain in the blood for a period after infection, and in the case of re-infection, they are able to tackle the virus again.

In their paper, published in Science today (Friday 6 November), the scientists found that some people, notably children, have antibodies reactive to SARS-CoV-2 in their blood, despite not ever having being infected with the virus. These antibodies are likely the result of exposure to other coronaviruses, which cause a common cold and which have structural similarities with SARS-CoV-2.

The researchers made this discovery while developing highly sensitive antibody tests for COVID-19. To see how well their assay tests were performing, they compared the blood of patients with COVID-19 to patients who had not had the disease. Surprisingly, they found that some people who had not been exposed to SARS-CoV-2 had antibodies in their blood which would recognise the virus. To confirm their findings, they analysed over 300 blood samples collected before the pandemic, between 2011 and 2018.

Nearly all samples had antibodies that reacted with common cold coronaviruses, which was expected given how everyone has been exposed to these viruses at some point in their lives. However, a small fraction of adult donors, about 1 in 20, also had antibodies that cross-reacted with SARS-CoV-2, and this was not dependent on recent infection with a common cold coronavirus.*

Notably, such cross-reactive antibodies were found much more frequently in blood samples taken from children aged 6 to 16.

Kevin Ng, lead author and post-graduate student in the Retroviral Immunology Laboratory at the Crick says: "Our results show that children are much more likely to have these cross-reactive antibodies than adults. More research is needed to understand why this is, but it could be down to children being more regularly exposed to other coronaviruses.

"These higher levels we observed in children could also help explain why they are less likely to become severely ill with COVID-19. There is no evidence yet, however, that these antibodies prevent SARS-CoV-2 infection or spread."

In the lab, the researchers tested the antibodies they found in blood from uninfected people to confirm they are able to neutralise SARS-CoV-2. They found the cross-reactive antibodies target the S2 subunit of the spike protein on the surface of the virus.

George Kassiotis, senior author and group leader of the Retroviral Immunology Laboratory at the Crick says: "The spike of this coronavirus is made of two parts or subunits, performing different jobs. The S1 subunit allows the virus to latch onto cells and is relatively diverse among coronaviruses, whereas the S2 subunit lets the virus into cells and is more similar among these viruses. Our work shows that the S2 subunit is sufficiently similar between common cold coronaviruses and SARS-CoV-2 for some antibodies to work against both.

"It was previously thought that only antibodies to the S1 could block infection, but there is now good evidence that some antibodies to S2 can be just as effective. This is exciting as understanding the basis for this activity could lead to vaccines that work against a range of coronaviruses, including the common cold strains, as well as SARS-CoV-2 and any future pandemic strains.

"But it is important to stress that there are still many unknowns which require further research. For example, exactly how is immunity to one coronavirus modified by exposure to another? Or why does this activity decline with age? It is not the case that people who have recently had a cold should think they are immune to COVID-19."

A large study is now underway, in partnership with researchers at Imperial College London and University College London, to uncover the role that different antibodies and other immune defences play in protection against COVID-19 and how severely ill people become.
-end-
For further information, contact: press@crick.ac.uk or +44 (0)20 3796 5252

Notes to Editors

Reference: Ng, K et al. (2020). Pre-existing and de novo humoral immunity to SARS-CoV-2 in humans. Science. DOI number: 10.1126/science.abe1107.

* The researchers found that: The Francis Crick Institute is a biomedical discovery institute dedicated to understanding the fundamental biology underlying health and disease. Its work is helping to understand why disease develops and to translate discoveries into new ways to prevent, diagnose and treat illnesses such as cancer, heart disease, stroke, infections, and neurodegenerative diseases.

An independent organisation, its founding partners are the Medical Research Council (MRC), Cancer Research UK, Wellcome, UCL (University College London), Imperial College London and King's College London.

The Crick was formed in 2015, and in 2016 it moved into a brand new state-of-the-art building in central London which brings together 1500 scientists and support staff working collaboratively across disciplines, making it the biggest biomedical research facility under a single roof in Europe.

http://crick.ac.uk/

The Francis Crick Institute

Related Immune System Articles from Brightsurf:

How the immune system remembers viruses
For a person to acquire immunity to a disease, T cells must develop into memory cells after contact with the pathogen.

How does the immune system develop in the first days of life?
Researchers highlight the anti-inflammatory response taking place after birth and designed to shield the newborn from infection.

Memory training for the immune system
The immune system will memorize the pathogen after an infection and can therefore react promptly after reinfection with the same pathogen.

Immune system may have another job -- combatting depression
An inflammatory autoimmune response within the central nervous system similar to one linked to neurodegenerative diseases such as multiple sclerosis (MS) has also been found in the spinal fluid of healthy people, according to a new Yale-led study comparing immune system cells in the spinal fluid of MS patients and healthy subjects.

COVID-19: Immune system derails
Contrary to what has been generally assumed so far, a severe course of COVID-19 does not solely result in a strong immune reaction - rather, the immune response is caught in a continuous loop of activation and inhibition.

Immune cell steroids help tumours suppress the immune system, offering new drug targets
Tumours found to evade the immune system by telling immune cells to produce immunosuppressive steroids.

Immune system -- Knocked off balance
Instead of protecting us, the immune system can sometimes go awry, as in the case of autoimmune diseases and allergies.

Too much salt weakens the immune system
A high-salt diet is not only bad for one's blood pressure, but also for the immune system.

Parkinson's and the immune system
Mutations in the Parkin gene are a common cause of hereditary forms of Parkinson's disease.

How an immune system regulator shifts the balance of immune cells
Researchers have provided new insight on the role of cyclic AMP (cAMP) in regulating the immune response.

Read More: Immune System News and Immune System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.