Acquired immunity against random food allergens may offer immunity against COVID-19 to few

A recent study in open-access journal Frontiers in Immunology finds that common foods, vaccines, bacteria and viruses may all prime our immune system to attack SARS-CoV-2, the virus that causes Covid-19. These agents all contain proteins that are similar to those found in SARS-CoV-2.

Proteins present in bacteria, human cells, vaccines, and even foods may all share similarities with those in SARS-CoV-2. The researchers behind this latest study hypothesized that similarities between SARS-CoV-2 and other common proteins may affect our susceptibility to the virus.

When our body is attacked by a pathogen, such as a virus or bacterium, it launches an immune response that involves antibodies. These immune proteins stick to specific parts of the pathogen and contribute to its destruction. After the initial infection has subsided, white blood cells called memory T and B cells will retain a memory of the pathogen, or at least certain parts of its structure. These cells will be ready to mount an immune response very rapidly if they ever encounter the pathogen again.

Could such an 'immune memory' to proteins we have encountered in our past underly immune resistance and reduced susceptibility to Covid-19? To begin to test this hypothesis, these researchers investigated whether antibodies that target proteins in the SARS-CoV-2 virus could also bind to proteins in other agents, such as foods or common bacteria.

The researchers tested the ability of these antibodies to bind to 180 different proteins from common foods, two different vaccines, and 15 bacterial and viral proteins. The antibodies reacted most strongly with a common gut bacterium called E. faecalis and a vaccine against diphtheria, tetanus, and pertussis. Interestingly, they also reacted very strongly against proteins found in common foods, including broccoli, roasted almonds, pork, cashews, milk, soy, and pineapple.

The study paves the way for new immunotherapies or vaccines that lead to stronger immunity against Covid-19.

Reference:

Dr Aristo Vodjani et al,Frontiers in Immunology